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diff --git a/doc/filters.texi b/doc/filters.texi index 8f90e84..725c7b5 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -1,3 +1,99 @@ +@chapter Filtering Introduction +@c man begin FILTERING INTRODUCTION + +Filtering in FFmpeg is enabled through the libavfilter library. + +Libavfilter is the filtering API of FFmpeg. It is the substitute of +the now deprecated 'vhooks' and started as a Google Summer of Code +project. + +Audio filtering integration into the main FFmpeg repository is a work in +progress, so audio API and ABI should not be considered stable yet. + +In libavfilter, it is possible for filters to have multiple inputs and +multiple outputs. +To illustrate the sorts of things that are possible, we can +use a complex filter graph. For example, the following one: + +@example +input --> split --> fifo -----------------------> overlay --> output + | ^ + | | + +------> fifo --> crop --> vflip --------+ +@end example + +splits the stream in two streams, sends one stream through the crop filter +and the vflip filter before merging it back with the other stream by +overlaying it on top. You can use the following command to achieve this: + +@example +ffmpeg -i input -vf "[in] split [T1], fifo, [T2] overlay=0:H/2 [out]; [T1] fifo, crop=iw:ih/2:0:ih/2, vflip [T2]" output +@end example + +The result will be that in output the top half of the video is mirrored +onto the bottom half. + +Filters are loaded using the @var{-vf} or @var{-af} option passed to +@command{ffmpeg} or to @command{ffplay}. Filters in the same linear +chain are separated by commas. In our example, @var{split, fifo, +overlay} are in one linear chain, and @var{fifo, crop, vflip} are in +another. The points where the linear chains join are labeled by names +enclosed in square brackets. In our example, that is @var{[T1]} and +@var{[T2]}. The special labels @var{[in]} and @var{[out]} are the points +where video is input and output. + +Some filters take in input a list of parameters: they are specified +after the filter name and an equal sign, and are separated from each other +by a colon. + +There exist so-called @var{source filters} that do not have an +audio/video input, and @var{sink filters} that will not have audio/video +output. + +@c man end FILTERING INTRODUCTION + +@chapter graph2dot +@c man begin GRAPH2DOT + +The @file{graph2dot} program included in the FFmpeg @file{tools} +directory can be used to parse a filter graph description and issue a +corresponding textual representation in the dot language. + +Invoke the command: +@example +graph2dot -h +@end example + +to see how to use @file{graph2dot}. + +You can then pass the dot description to the @file{dot} program (from +the graphviz suite of programs) and obtain a graphical representation +of the filter graph. + +For example the sequence of commands: +@example +echo @var{GRAPH_DESCRIPTION} | \ +tools/graph2dot -o graph.tmp && \ +dot -Tpng graph.tmp -o graph.png && \ +display graph.png +@end example + +can be used to create and display an image representing the graph +described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be +a complete self-contained graph, with its inputs and outputs explicitly defined. +For example if your command line is of the form: +@example +ffmpeg -i infile -vf scale=640:360 outfile +@end example +your @var{GRAPH_DESCRIPTION} string will need to be of the form: +@example +nullsrc,scale=640:360,nullsink +@end example +you may also need to set the @var{nullsrc} parameters and add a @var{format} +filter in order to simulate a specific input file. + +@c man end GRAPH2DOT + @chapter Filtergraph description @c man begin FILTERGRAPH DESCRIPTION @@ -19,7 +115,7 @@ output pads is called a "sink". A filtergraph can be represented using a textual representation, which is recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex} -options in @command{avconv} and @option{-vf} in @command{avplay}, and by the +options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in @file{libavfilter/avfiltergraph.h}. @@ -100,13 +196,46 @@ Follows a BNF description for the filtergraph syntax: @chapter Audio Filters @c man begin AUDIO FILTERS -When you configure your Libav build, you can disable any of the -existing filters using --disable-filters. +When you configure your FFmpeg build, you can disable any of the +existing filters using @code{--disable-filters}. The configure output will show the audio filters included in your build. Below is a description of the currently available audio filters. +@section aconvert + +Convert the input audio format to the specified formats. + +The filter accepts a string of the form: +"@var{sample_format}:@var{channel_layout}". + +@var{sample_format} specifies the sample format, and can be a string or the +corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p' +suffix for a planar sample format. + +@var{channel_layout} specifies the channel layout, and can be a string +or the corresponding number value defined in @file{libavutil/audioconvert.h}. + +The special parameter "auto", signifies that the filter will +automatically select the output format depending on the output filter. + +Some examples follow. + +@itemize +@item +Convert input to float, planar, stereo: +@example +aconvert=fltp:stereo +@end example + +@item +Convert input to unsigned 8-bit, automatically select out channel layout: +@example +aconvert=u8:auto +@end example +@end itemize + @section aformat Convert the input audio to one of the specified formats. The framework will @@ -133,13 +262,65 @@ For example to force the output to either unsigned 8-bit or signed 16-bit stereo aformat=sample_fmts\=u8\,s16:channel_layouts\=stereo @end example +@section amerge + +Merge two or more audio streams into a single multi-channel stream. + +The filter accepts the following named options: + +@table @option + +@item inputs +Set the number of inputs. Default is 2. + +@end table + +If the channel layouts of the inputs are disjoint, and therefore compatible, +the channel layout of the output will be set accordingly and the channels +will be reordered as necessary. If the channel layouts of the inputs are not +disjoint, the output will have all the channels of the first input then all +the channels of the second input, in that order, and the channel layout of +the output will be the default value corresponding to the total number of +channels. + +For example, if the first input is in 2.1 (FL+FR+LF) and the second input +is FC+BL+BR, then the output will be in 5.1, with the channels in the +following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the +first input, b1 is the first channel of the second input). + +On the other hand, if both input are in stereo, the output channels will be +in the default order: a1, a2, b1, b2, and the channel layout will be +arbitrarily set to 4.0, which may or may not be the expected value. + +All inputs must have the same sample rate, and format. + +If inputs do not have the same duration, the output will stop with the +shortest. + +Example: merge two mono files into a stereo stream: +@example +amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge +@end example + +Example: multiple merges: +@example +ffmpeg -f lavfi -i " +amovie=input.mkv:si=0 [a0]; +amovie=input.mkv:si=1 [a1]; +amovie=input.mkv:si=2 [a2]; +amovie=input.mkv:si=3 [a3]; +amovie=input.mkv:si=4 [a4]; +amovie=input.mkv:si=5 [a5]; +[a0][a1][a2][a3][a4][a5] amerge=inputs=6" -c:a pcm_s16le output.mkv +@end example + @section amix Mixes multiple audio inputs into a single output. For example @example -avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT +ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT @end example will mix 3 input audio streams to a single output with the same duration as the first input and a dropout transition time of 3 seconds. @@ -175,6 +356,97 @@ stream ends. The default value is 2 seconds. Pass the audio source unchanged to the output. +@section aresample + +Resample the input audio to the specified sample rate. + +The filter accepts exactly one parameter, the output sample rate. If not +specified then the filter will automatically convert between its input +and output sample rates. + +For example, to resample the input audio to 44100Hz: +@example +aresample=44100 +@end example + +@section asetnsamples + +Set the number of samples per each output audio frame. + +The last output packet may contain a different number of samples, as +the filter will flush all the remaining samples when the input audio +signal its end. + +The filter accepts parameters as a list of @var{key}=@var{value} pairs, +separated by ":". + +@table @option + +@item nb_out_samples, n +Set the number of frames per each output audio frame. The number is +intended as the number of samples @emph{per each channel}. +Default value is 1024. + +@item pad, p +If set to 1, the filter will pad the last audio frame with zeroes, so +that the last frame will contain the same number of samples as the +previous ones. Default value is 1. +@end table + +For example, to set the number of per-frame samples to 1234 and +disable padding for the last frame, use: +@example +asetnsamples=n=1234:p=0 +@end example + +@section ashowinfo + +Show a line containing various information for each input audio frame. +The input audio is not modified. + +The shown line contains a sequence of key/value pairs of the form +@var{key}:@var{value}. + +A description of each shown parameter follows: + +@table @option +@item n +sequential number of the input frame, starting from 0 + +@item pts +presentation TimeStamp of the input frame, expressed as a number of +time base units. The time base unit depends on the filter input pad, and +is usually 1/@var{sample_rate}. + +@item pts_time +presentation TimeStamp of the input frame, expressed as a number of +seconds + +@item pos +position of the frame in the input stream, -1 if this information in +unavailable and/or meaningless (for example in case of synthetic audio) + +@item fmt +sample format name + +@item chlayout +channel layout description + +@item nb_samples +number of samples (per each channel) contained in the filtered frame + +@item rate +sample rate for the audio frame + +@item checksum +Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame + +@item plane_checksum +Adler-32 checksum (printed in hexadecimal) for each input frame plane, +expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3} @var{c4} @var{c5} +@var{c6} @var{c7}]" +@end table + @section asplit Split input audio into several identical outputs. @@ -182,12 +454,293 @@ Split input audio into several identical outputs. The filter accepts a single parameter which specifies the number of outputs. If unspecified, it defaults to 2. -For example +For example: +@example +[in] asplit [out0][out1] +@end example + +will create two separate outputs from the same input. + +To create 3 or more outputs, you need to specify the number of +outputs, like in: @example -avconv -i INPUT -filter_complex asplit=5 OUTPUT +[in] asplit=3 [out0][out1][out2] +@end example + +@example +ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT @end example will create 5 copies of the input audio. + +@section astreamsync + +Forward two audio streams and control the order the buffers are forwarded. + +The argument to the filter is an expression deciding which stream should be +forwarded next: if the result is negative, the first stream is forwarded; if +the result is positive or zero, the second stream is forwarded. It can use +the following variables: + +@table @var +@item b1 b2 +number of buffers forwarded so far on each stream +@item s1 s2 +number of samples forwarded so far on each stream +@item t1 t2 +current timestamp of each stream +@end table + +The default value is @code{t1-t2}, which means to always forward the stream +that has a smaller timestamp. + +Example: stress-test @code{amerge} by randomly sending buffers on the wrong +input, while avoiding too much of a desynchronization: +@example +amovie=file.ogg [a] ; amovie=file.mp3 [b] ; +[a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ; +[a2] [b2] amerge +@end example + +@section atempo + +Adjust audio tempo. + +The filter accepts exactly one parameter, the audio tempo. If not +specified then the filter will assume nominal 1.0 tempo. Tempo must +be in the [0.5, 2.0] range. + +For example, to slow down audio to 80% tempo: +@example +atempo=0.8 +@end example + +For example, to speed up audio to 125% tempo: +@example +atempo=1.25 +@end example + +@section earwax + +Make audio easier to listen to on headphones. + +This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio +so that when listened to on headphones the stereo image is moved from +inside your head (standard for headphones) to outside and in front of +the listener (standard for speakers). + +Ported from SoX. + +@section pan + +Mix channels with specific gain levels. The filter accepts the output +channel layout followed by a set of channels definitions. + +This filter is also designed to remap efficiently the channels of an audio +stream. + +The filter accepts parameters of the form: +"@var{l}:@var{outdef}:@var{outdef}:..." + +@table @option +@item l +output channel layout or number of channels + +@item outdef +output channel specification, of the form: +"@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]" + +@item out_name +output channel to define, either a channel name (FL, FR, etc.) or a channel +number (c0, c1, etc.) + +@item gain +multiplicative coefficient for the channel, 1 leaving the volume unchanged + +@item in_name +input channel to use, see out_name for details; it is not possible to mix +named and numbered input channels +@end table + +If the `=' in a channel specification is replaced by `<', then the gains for +that specification will be renormalized so that the total is 1, thus +avoiding clipping noise. + +@subsection Mixing examples + +For example, if you want to down-mix from stereo to mono, but with a bigger +factor for the left channel: +@example +pan=1:c0=0.9*c0+0.1*c1 +@end example + +A customized down-mix to stereo that works automatically for 3-, 4-, 5- and +7-channels surround: +@example +pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR +@end example + +Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system +that should be preferred (see "-ac" option) unless you have very specific +needs. + +@subsection Remapping examples + +The channel remapping will be effective if, and only if: + +@itemize +@item gain coefficients are zeroes or ones, +@item only one input per channel output, +@end itemize + +If all these conditions are satisfied, the filter will notify the user ("Pure +channel mapping detected"), and use an optimized and lossless method to do the +remapping. + +For example, if you have a 5.1 source and want a stereo audio stream by +dropping the extra channels: +@example +pan="stereo: c0=FL : c1=FR" +@end example + +Given the same source, you can also switch front left and front right channels +and keep the input channel layout: +@example +pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5" +@end example + +If the input is a stereo audio stream, you can mute the front left channel (and +still keep the stereo channel layout) with: +@example +pan="stereo:c1=c1" +@end example + +Still with a stereo audio stream input, you can copy the right channel in both +front left and right: +@example +pan="stereo: c0=FR : c1=FR" +@end example + +@section silencedetect + +Detect silence in an audio stream. + +This filter logs a message when it detects that the input audio volume is less +or equal to a noise tolerance value for a duration greater or equal to the +minimum detected noise duration. + +The printed times and duration are expressed in seconds. + +@table @option +@item duration, d +Set silence duration until notification (default is 2 seconds). + +@item noise, n +Set noise tolerance. Can be specified in dB (in case "dB" is appended to the +specified value) or amplitude ratio. Default is -60dB, or 0.001. +@end table + +Detect 5 seconds of silence with -50dB noise tolerance: +@example +silencedetect=n=-50dB:d=5 +@end example + +Complete example with @command{ffmpeg} to detect silence with 0.0001 noise +tolerance in @file{silence.mp3}: +@example +ffmpeg -f lavfi -i amovie=silence.mp3,silencedetect=noise=0.0001 -f null - +@end example + +@section volume + +Adjust the input audio volume. + +The filter accepts exactly one parameter @var{vol}, which expresses +how the audio volume will be increased or decreased. + +Output values are clipped to the maximum value. + +If @var{vol} is expressed as a decimal number, the output audio +volume is given by the relation: +@example +@var{output_volume} = @var{vol} * @var{input_volume} +@end example + +If @var{vol} is expressed as a decimal number followed by the string +"dB", the value represents the requested change in decibels of the +input audio power, and the output audio volume is given by the +relation: +@example +@var{output_volume} = 10^(@var{vol}/20) * @var{input_volume} +@end example + +Otherwise @var{vol} is considered an expression and its evaluated +value is used for computing the output audio volume according to the +first relation. + +Default value for @var{vol} is 1.0. + +@subsection Examples + +@itemize +@item +Half the input audio volume: +@example +volume=0.5 +@end example + +The above example is equivalent to: +@example +volume=1/2 +@end example + +@item +Decrease input audio power by 12 decibels: +@example +volume=-12dB +@end example +@end itemize + +@section volumedetect + +Detect the volume of the input video. + +The filter has no parameters. The input is not modified. Statistics about +the volume will be printed in the log when the input stream end is reached. + +In particular it will show the mean volume (root mean square), maximum +volume (on a per-sample basis), and the beginning of an histogram of the +registered volume values (from the maximum value to a cumulated 1/1000 of +the samples). + +All volumes are in decibels relative to the maximum PCM value. + +Here is an excerpt of the output: +@example +[Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB +[Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB +[Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6 +[Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62 +[Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286 +[Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042 +[Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551 +[Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609 +[Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409 +@end example + +It means that: +@itemize +@item +The mean square energy is approximately -27 dB, or 10^-2.7. +@item +The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB. +@item +There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc. +@end itemize + +In other words, raising the volume by +4 dB does not cause any clipping, +raising it by +5 dB causes clipping for 6 samples, etc. + @section asyncts Synchronize audio data with timestamps by squeezing/stretching it and/or dropping samples/adding silence when needed. @@ -228,14 +781,14 @@ Channel layout of the input stream. Default is "stereo". For example, assuming a stereo input MP3 file @example -avconv -i in.mp3 -filter_complex channelsplit out.mkv +ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv @end example will create an output Matroska file with two audio streams, one containing only the left channel and the other the right channel. To split a 5.1 WAV file into per-channel files @example -avconv -i in.wav -filter_complex +ffmpeg -i in.wav -filter_complex 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]' -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]' front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]' @@ -265,14 +818,14 @@ output channels preserving index. For example, assuming a 5.1+downmix input MOV file @example -avconv -i in.mov -filter 'channelmap=map=DL-FL\,DR-FR' out.wav +ffmpeg -i in.mov -filter 'channelmap=map=DL-FL\,DR-FR' out.wav @end example will create an output WAV file tagged as stereo from the downmix channels of the input. To fix a 5.1 WAV improperly encoded in AAC's native channel order @example -avconv -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav +ffmpeg -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav @end example @section join @@ -302,21 +855,19 @@ and if that fails it picks the first unused input channel. E.g. to join 3 inputs (with properly set channel layouts) @example -avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT +ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT @end example To build a 5.1 output from 6 single-channel streams: @example -avconv -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex +ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex 'join=inputs=6:channel_layout=5.1:map=0.0-FL\,1.0-FR\,2.0-FC\,3.0-SL\,4.0-SR\,5.0-LFE' out @end example @section resample Convert the audio sample format, sample rate and channel layout. This filter is -not meant to be used directly, it is inserted automatically by libavfilter -whenever conversion is needed. Use the @var{aformat} filter to force a specific -conversion. +not meant to be used directly. @c man end AUDIO FILTERS @@ -325,31 +876,188 @@ conversion. Below is a description of the currently available audio sources. +@section abuffer + +Buffer audio frames, and make them available to the filter chain. + +This source is mainly intended for a programmatic use, in particular +through the interface defined in @file{libavfilter/asrc_abuffer.h}. + +It accepts the following mandatory parameters: +@var{sample_rate}:@var{sample_fmt}:@var{channel_layout} + +@table @option + +@item sample_rate +The sample rate of the incoming audio buffers. + +@item sample_fmt +The sample format of the incoming audio buffers. +Either a sample format name or its corresponging integer representation from +the enum AVSampleFormat in @file{libavutil/samplefmt.h} + +@item channel_layout +The channel layout of the incoming audio buffers. +Either a channel layout name from channel_layout_map in +@file{libavutil/audioconvert.c} or its corresponding integer representation +from the AV_CH_LAYOUT_* macros in @file{libavutil/audioconvert.h} + +@end table + +For example: +@example +abuffer=44100:s16p:stereo +@end example + +will instruct the source to accept planar 16bit signed stereo at 44100Hz. +Since the sample format with name "s16p" corresponds to the number +6 and the "stereo" channel layout corresponds to the value 0x3, this is +equivalent to: +@example +abuffer=44100:6:0x3 +@end example + +@section aevalsrc + +Generate an audio signal specified by an expression. + +This source accepts in input one or more expressions (one for each +channel), which are evaluated and used to generate a corresponding +audio signal. + +It accepts the syntax: @var{exprs}[::@var{options}]. +@var{exprs} is a list of expressions separated by ":", one for each +separate channel. In case the @var{channel_layout} is not +specified, the selected channel layout depends on the number of +provided expressions. + +@var{options} is an optional sequence of @var{key}=@var{value} pairs, +separated by ":". + +The description of the accepted options follows. + +@table @option + +@item channel_layout, c +Set the channel layout. The number of channels in the specified layout +must be equal to the number of specified expressions. + +@item duration, d +Set the minimum duration of the sourced audio. See the function +@code{av_parse_time()} for the accepted format. +Note that the resulting duration may be greater than the specified +duration, as the generated audio is always cut at the end of a +complete frame. + +If not specified, or the expressed duration is negative, the audio is +supposed to be generated forever. + +@item nb_samples, n +Set the number of samples per channel per each output frame, +default to 1024. + +@item sample_rate, s +Specify the sample rate, default to 44100. +@end table + +Each expression in @var{exprs} can contain the following constants: + +@table @option +@item n +number of the evaluated sample, starting from 0 + +@item t +time of the evaluated sample expressed in seconds, starting from 0 + +@item s +sample rate + +@end table + +@subsection Examples + +@itemize + +@item +Generate silence: +@example +aevalsrc=0 +@end example + +@item + +Generate a sin signal with frequency of 440 Hz, set sample rate to +8000 Hz: +@example +aevalsrc="sin(440*2*PI*t)::s=8000" +@end example + +@item +Generate a two channels signal, specify the channel layout (Front +Center + Back Center) explicitly: +@example +aevalsrc="sin(420*2*PI*t):cos(430*2*PI*t)::c=FC|BC" +@end example + +@item +Generate white noise: +@example +aevalsrc="-2+random(0)" +@end example + +@item +Generate an amplitude modulated signal: +@example +aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)" +@end example + +@item +Generate 2.5 Hz binaural beats on a 360 Hz carrier: +@example +aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) : 0.1*sin(2*PI*(360+2.5/2)*t)" +@end example + +@end itemize + @section anullsrc -Null audio source, never return audio frames. It is mainly useful as a -template and to be employed in analysis / debugging tools. +Null audio source, return unprocessed audio frames. It is mainly useful +as a template and to be employed in analysis / debugging tools, or as +the source for filters which ignore the input data (for example the sox +synth filter). + +It accepts an optional sequence of @var{key}=@var{value} pairs, +separated by ":". + +The description of the accepted options follows. + +@table @option -It accepts as optional parameter a string of the form -@var{sample_rate}:@var{channel_layout}. +@item sample_rate, s +Specify the sample rate, and defaults to 44100. -@var{sample_rate} specify the sample rate, and defaults to 44100. +@item channel_layout, cl -@var{channel_layout} specify the channel layout, and can be either an -integer or a string representing a channel layout. The default value -of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO. +Specify the channel layout, and can be either an integer or a string +representing a channel layout. The default value of @var{channel_layout} +is "stereo". Check the channel_layout_map definition in @file{libavcodec/audioconvert.c} for the mapping between strings and channel layout values. +@item nb_samples, n +Set the number of samples per requested frames. + +@end table + Follow some examples: @example -# set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO. -anullsrc=48000:4 +# set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO. +anullsrc=r=48000:cl=4 # same as -anullsrc=48000:mono +anullsrc=r=48000:cl=mono @end example @section abuffer @@ -379,6 +1087,67 @@ Channel layout of the audio data, in the form that can be accepted by All the parameters need to be explicitly defined. +@section flite + +Synthesize a voice utterance using the libflite library. + +To enable compilation of this filter you need to configure FFmpeg with +@code{--enable-libflite}. + +Note that the flite library is not thread-safe. + +The source accepts parameters as a list of @var{key}=@var{value} pairs, +separated by ":". + +The description of the accepted parameters follows. + +@table @option + +@item list_voices +If set to 1, list the names of the available voices and exit +immediately. Default value is 0. + +@item nb_samples, n +Set the maximum number of samples per frame. Default value is 512. + +@item textfile +Set the filename containing the text to speak. + +@item text +Set the text to speak. + +@item voice, v +Set the voice to use for the speech synthesis. Default value is +@code{kal}. See also the @var{list_voices} option. +@end table + +@subsection Examples + +@itemize +@item +Read from file @file{speech.txt}, and synthetize the text using the +standard flite voice: +@example +flite=textfile=speech.txt +@end example + +@item +Read the specified text selecting the @code{slt} voice: +@example +flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt +@end example + +@item +Make @file{ffplay} speech the specified text, using @code{flite} and +the @code{lavfi} device: +@example +ffplay -f lavfi flite='No more be grieved for which that thou hast done.' +@end example +@end itemize + +For more information about libflite, check: +@url{http://www.speech.cs.cmu.edu/flite/} + @c man end AUDIO SOURCES @chapter Audio Sinks @@ -386,6 +1155,17 @@ All the parameters need to be explicitly defined. Below is a description of the currently available audio sinks. +@section abuffersink + +Buffer audio frames, and make them available to the end of filter chain. + +This sink is mainly intended for programmatic use, in particular +through the interface defined in @file{libavfilter/buffersink.h}. + +It requires a pointer to an AVABufferSinkContext structure, which +defines the incoming buffers' formats, to be passed as the opaque +parameter to @code{avfilter_init_filter} for initialization. + @section anullsink Null audio sink, do absolutely nothing with the input audio. It is @@ -404,13 +1184,130 @@ This filter accepts no parameters. @chapter Video Filters @c man begin VIDEO FILTERS -When you configure your Libav build, you can disable any of the -existing filters using --disable-filters. +When you configure your FFmpeg build, you can disable any of the +existing filters using @code{--disable-filters}. The configure output will show the video filters included in your build. Below is a description of the currently available video filters. +@section alphaextract + +Extract the alpha component from the input as a grayscale video. This +is especially useful with the @var{alphamerge} filter. + +@section alphamerge + +Add or replace the alpha component of the primary input with the +grayscale value of a second input. This is intended for use with +@var{alphaextract} to allow the transmission or storage of frame +sequences that have alpha in a format that doesn't support an alpha +channel. + +For example, to reconstruct full frames from a normal YUV-encoded video +and a separate video created with @var{alphaextract}, you might use: +@example +movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out] +@end example + +Since this filter is designed for reconstruction, it operates on frame +sequences without considering timestamps, and terminates when either +input reaches end of stream. This will cause problems if your encoding +pipeline drops frames. If you're trying to apply an image as an +overlay to a video stream, consider the @var{overlay} filter instead. + +@section ass + +Draw ASS (Advanced Substation Alpha) subtitles on top of input video +using the libass library. + +To enable compilation of this filter you need to configure FFmpeg with +@code{--enable-libass}. + +This filter accepts the syntax: @var{ass_filename}[:@var{options}], +where @var{ass_filename} is the filename of the ASS file to read, and +@var{options} is an optional sequence of @var{key}=@var{value} pairs, +separated by ":". + +A description of the accepted options follows. + +@table @option +@item original_size +Specifies the size of the original video, the video for which the ASS file +was composed. Due to a misdesign in ASS aspect ratio arithmetic, this is +necessary to correctly scale the fonts if the aspect ratio has been changed. +@end table + +For example, to render the file @file{sub.ass} on top of the input +video, use the command: +@example +ass=sub.ass +@end example + +@section bbox + +Compute the bounding box for the non-black pixels in the input frame +luminance plane. + +This filter computes the bounding box containing all the pixels with a +luminance value greater than the minimum allowed value. +The parameters describing the bounding box are printed on the filter +log. + +@section blackdetect + +Detect video intervals that are (almost) completely black. Can be +useful to detect chapter transitions, commercials, or invalid +recordings. Output lines contains the time for the start, end and +duration of the detected black interval expressed in seconds. + +In order to display the output lines, you need to set the loglevel at +least to the AV_LOG_INFO value. + +This filter accepts a list of options in the form of +@var{key}=@var{value} pairs separated by ":". A description of the +accepted options follows. + +@table @option +@item black_min_duration, d +Set the minimum detected black duration expressed in seconds. It must +be a non-negative floating point number. + +Default value is 2.0. + +@item picture_black_ratio_th, pic_th +Set the threshold for considering a picture "black". +Express the minimum value for the ratio: +@example +@var{nb_black_pixels} / @var{nb_pixels} +@end example + +for which a picture is considered black. +Default value is 0.98. + +@item pixel_black_th, pix_th +Set the threshold for considering a pixel "black". + +The threshold expresses the maximum pixel luminance value for which a +pixel is considered "black". The provided value is scaled according to +the following equation: +@example +@var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size} +@end example + +@var{luminance_range_size} and @var{luminance_minimum_value} depend on +the input video format, the range is [0-255] for YUV full-range +formats and [16-235] for YUV non full-range formats. + +Default value is 0.10. +@end table + +The following example sets the maximum pixel threshold to the minimum +value, and detects only black intervals of 2 or more seconds: +@example +blackdetect=d=2:pix_th=0.00 +@end example + @section blackframe Detect frames that are (almost) completely black. Can be useful to @@ -437,7 +1334,7 @@ considered black, and defaults to 32. Apply boxblur algorithm to the input video. This filter accepts the parameters: -@var{luma_power}:@var{luma_radius}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power} +@var{luma_radius}:@var{luma_power}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power} Chroma and alpha parameters are optional, if not specified they default to the corresponding values set for @var{luma_radius} and @@ -492,6 +1389,18 @@ boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1 @end itemize +@section colormatrix + +The colormatrix filter allows conversion between any of the following color +space: BT.709 (@var{bt709}), BT.601 (@var{bt601}), SMPTE-240M (@var{smpte240m}) +and FCC (@var{fcc}). + +The syntax of the parameters is @var{source}:@var{destination}: + +@example +colormatrix=bt601:smpte240m +@end example + @section copy Copy the input source unchanged to the output. Mainly useful for @@ -499,15 +1408,16 @@ testing purposes. @section crop -Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}. +Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}:@var{keep_aspect} -The parameters are expressions containing the following constants: +The @var{keep_aspect} parameter is optional, if specified and set to a +non-zero value will force the output display aspect ratio to be the +same of the input, by changing the output sample aspect ratio. -@table @option -@item E, PI, PHI -the corresponding mathematical approximated values for e -(euler number), pi (greek PI), PHI (golden ratio) +The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are +expressions containing the following constants: +@table @option @item x, y the computed values for @var{x} and @var{y}. They are evaluated for each new frame. @@ -524,6 +1434,19 @@ the output (cropped) width and height @item ow, oh same as @var{out_w} and @var{out_h} +@item a +same as @var{iw} / @var{ih} + +@item sar +input sample aspect ratio + +@item dar +input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar} + +@item hsub, vsub +horizontal and vertical chroma subsample values. For example for the +pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. + @item n the number of input frame, starting from 0 @@ -630,6 +1553,43 @@ indicates never reset and return the largest area encountered during playback. @end table +@section decimate + +This filter drops frames that do not differ greatly from the previous +frame in order to reduce framerate. The main use of this filter is +for very-low-bitrate encoding (e.g. streaming over dialup modem), but +it could in theory be used for fixing movies that were +inverse-telecined incorrectly. + +It accepts the following parameters: +@var{max}:@var{hi}:@var{lo}:@var{frac}. + +@table @option + +@item max +Set the maximum number of consecutive frames which can be dropped (if +positive), or the minimum interval between dropped frames (if +negative). If the value is 0, the frame is dropped unregarding the +number of previous sequentially dropped frames. + +Default value is 0. + +@item hi, lo, frac +Set the dropping threshold values. + +Values for @var{hi} and @var{lo} are for 8x8 pixel blocks and +represent actual pixel value differences, so a threshold of 64 +corresponds to 1 unit of difference for each pixel, or the same spread +out differently over the block. + +A frame is a candidate for dropping if no 8x8 blocks differ by more +than a threshold of @var{hi}, and if no more than @var{frac} blocks (1 +meaning the whole image) differ by more than a threshold of @var{lo}. + +Default value for @var{hi} is 64*12, default value for @var{lo} is +64*5, and default value for @var{frac} is 0.33. +@end table + @section delogo Suppress a TV station logo by a simple interpolation of the surrounding @@ -682,6 +1642,76 @@ delogo=x=0:y=0:w=100:h=77:band=10 @end itemize +@section deshake + +Attempt to fix small changes in horizontal and/or vertical shift. This +filter helps remove camera shake from hand-holding a camera, bumping a +tripod, moving on a vehicle, etc. + +The filter accepts parameters as a string of the form +"@var{x}:@var{y}:@var{w}:@var{h}:@var{rx}:@var{ry}:@var{edge}:@var{blocksize}:@var{contrast}:@var{search}:@var{filename}" + +A description of the accepted parameters follows. + +@table @option + +@item x, y, w, h +Specify a rectangular area where to limit the search for motion +vectors. +If desired the search for motion vectors can be limited to a +rectangular area of the frame defined by its top left corner, width +and height. These parameters have the same meaning as the drawbox +filter which can be used to visualise the position of the bounding +box. + +This is useful when simultaneous movement of subjects within the frame +might be confused for camera motion by the motion vector search. + +If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1 +then the full frame is used. This allows later options to be set +without specifying the bounding box for the motion vector search. + +Default - search the whole frame. + +@item rx, ry +Specify the maximum extent of movement in x and y directions in the +range 0-64 pixels. Default 16. + +@item edge +Specify how to generate pixels to fill blanks at the edge of the +frame. An integer from 0 to 3 as follows: +@table @option +@item 0 +Fill zeroes at blank locations +@item 1 +Original image at blank locations +@item 2 +Extruded edge value at blank locations +@item 3 +Mirrored edge at blank locations +@end table + +The default setting is mirror edge at blank locations. + +@item blocksize +Specify the blocksize to use for motion search. Range 4-128 pixels, +default 8. + +@item contrast +Specify the contrast threshold for blocks. Only blocks with more than +the specified contrast (difference between darkest and lightest +pixels) will be considered. Range 1-255, default 125. + +@item search +Specify the search strategy 0 = exhaustive search, 1 = less exhaustive +search. Default - exhaustive search. + +@item filename +If set then a detailed log of the motion search is written to the +specified file. + +@end table + @section drawbox Draw a colored box on the input image. @@ -719,7 +1749,7 @@ drawbox=10:20:200:60:red@@0.5" Draw text string or text from specified file on top of video using the libfreetype library. -To enable compilation of this filter you need to configure Libav with +To enable compilation of this filter you need to configure FFmpeg with @code{--enable-libfreetype}. The filter also recognizes strftime() sequences in the provided text @@ -732,60 +1762,29 @@ The description of the accepted parameters follows. @table @option -@item fontfile -The font file to be used for drawing text. Path must be included. -This parameter is mandatory. - -@item text -The text string to be drawn. The text must be a sequence of UTF-8 -encoded characters. -This parameter is mandatory if no file is specified with the parameter -@var{textfile}. - -@item textfile -A text file containing text to be drawn. The text must be a sequence -of UTF-8 encoded characters. - -This parameter is mandatory if no text string is specified with the -parameter @var{text}. - -If both text and textfile are specified, an error is thrown. - -@item x, y -The offsets where text will be drawn within the video frame. -Relative to the top/left border of the output image. -They accept expressions similar to the @ref{overlay} filter: -@table @option - -@item x, y -the computed values for @var{x} and @var{y}. They are evaluated for -each new frame. - -@item main_w, main_h -main input width and height - -@item W, H -same as @var{main_w} and @var{main_h} - -@item text_w, text_h -rendered text width and height +@item box +Used to draw a box around text using background color. +Value should be either 1 (enable) or 0 (disable). +The default value of @var{box} is 0. -@item w, h -same as @var{text_w} and @var{text_h} +@item boxcolor +The color to be used for drawing box around text. +Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format +(e.g. "0xff00ff"), possibly followed by an alpha specifier. +The default value of @var{boxcolor} is "white". -@item n -the number of frames processed, starting from 0 +@item draw +Set an expression which specifies if the text should be drawn. If the +expression evaluates to 0, the text is not drawn. This is useful for +specifying that the text should be drawn only when specific conditions +are met. -@item t -timestamp expressed in seconds, NAN if the input timestamp is unknown +Default value is "1". -@end table +See below for the list of accepted constants and functions. -The default value of @var{x} and @var{y} is 0. - -@item fontsize -The font size to be used for drawing text. -The default value of @var{fontsize} is 16. +@item fix_bounds +If true, check and fix text coords to avoid clipping. @item fontcolor The color to be used for drawing fonts. @@ -793,27 +1792,13 @@ Either a string (e.g. "red") or in 0xRRGGBB[AA] format (e.g. "0xff000033"), possibly followed by an alpha specifier. The default value of @var{fontcolor} is "black". -@item boxcolor -The color to be used for drawing box around text. -Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format -(e.g. "0xff00ff"), possibly followed by an alpha specifier. -The default value of @var{boxcolor} is "white". - -@item box -Used to draw a box around text using background color. -Value should be either 1 (enable) or 0 (disable). -The default value of @var{box} is 0. - -@item shadowx, shadowy -The x and y offsets for the text shadow position with respect to the -position of the text. They can be either positive or negative -values. Default value for both is "0". +@item fontfile +The font file to be used for drawing text. Path must be included. +This parameter is mandatory. -@item shadowcolor -The color to be used for drawing a shadow behind the drawn text. It -can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA] -form (e.g. "0xff00ff"), possibly followed by an alpha specifier. -The default value of @var{shadowcolor} is "black". +@item fontsize +The font size to be used for drawing text. +The default value of @var{fontsize} is 16. @item ft_load_flags Flags to be used for loading the fonts. @@ -844,45 +1829,230 @@ Default value is "render". For more information consult the documentation for the FT_LOAD_* libfreetype flags. +@item shadowcolor +The color to be used for drawing a shadow behind the drawn text. It +can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA] +form (e.g. "0xff00ff"), possibly followed by an alpha specifier. +The default value of @var{shadowcolor} is "black". + +@item shadowx, shadowy +The x and y offsets for the text shadow position with respect to the +position of the text. They can be either positive or negative +values. Default value for both is "0". + @item tabsize The size in number of spaces to use for rendering the tab. Default value is 4. -@item fix_bounds -If true, check and fix text coords to avoid clipping. +@item timecode +Set the initial timecode representation in "hh:mm:ss[:;.]ff" +format. It can be used with or without text parameter. @var{timecode_rate} +option must be specified. + +@item timecode_rate, rate, r +Set the timecode frame rate (timecode only). + +@item text +The text string to be drawn. The text must be a sequence of UTF-8 +encoded characters. +This parameter is mandatory if no file is specified with the parameter +@var{textfile}. + +@item textfile +A text file containing text to be drawn. The text must be a sequence +of UTF-8 encoded characters. + +This parameter is mandatory if no text string is specified with the +parameter @var{text}. + +If both @var{text} and @var{textfile} are specified, an error is thrown. + +@item x, y +The expressions which specify the offsets where text will be drawn +within the video frame. They are relative to the top/left border of the +output image. + +The default value of @var{x} and @var{y} is "0". + +See below for the list of accepted constants and functions. @end table -For example the command: +The parameters for @var{x} and @var{y} are expressions containing the +following constants and functions: + +@table @option +@item dar +input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar} + +@item hsub, vsub +horizontal and vertical chroma subsample values. For example for the +pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. + +@item line_h, lh +the height of each text line + +@item main_h, h, H +the input height + +@item main_w, w, W +the input width + +@item max_glyph_a, ascent +the maximum distance from the baseline to the highest/upper grid +coordinate used to place a glyph outline point, for all the rendered +glyphs. +It is a positive value, due to the grid's orientation with the Y axis +upwards. + +@item max_glyph_d, descent +the maximum distance from the baseline to the lowest grid coordinate +used to place a glyph outline point, for all the rendered glyphs. +This is a negative value, due to the grid's orientation, with the Y axis +upwards. + +@item max_glyph_h +maximum glyph height, that is the maximum height for all the glyphs +contained in the rendered text, it is equivalent to @var{ascent} - +@var{descent}. + +@item max_glyph_w +maximum glyph width, that is the maximum width for all the glyphs +contained in the rendered text + +@item n +the number of input frame, starting from 0 + +@item rand(min, max) +return a random number included between @var{min} and @var{max} + +@item sar +input sample aspect ratio + +@item t +timestamp expressed in seconds, NAN if the input timestamp is unknown + +@item text_h, th +the height of the rendered text + +@item text_w, tw +the width of the rendered text + +@item x, y +the x and y offset coordinates where the text is drawn. + +These parameters allow the @var{x} and @var{y} expressions to refer +each other, so you can for example specify @code{y=x/dar}. +@end table + +If libavfilter was built with @code{--enable-fontconfig}, then +@option{fontfile} can be a fontconfig pattern or omitted. + +Some examples follow. + +@itemize + +@item +Draw "Test Text" with font FreeSerif, using the default values for the +optional parameters. + @example drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'" @end example -will draw "Test Text" with font FreeSerif, using the default values -for the optional parameters. +@item +Draw 'Test Text' with font FreeSerif of size 24 at position x=100 +and y=50 (counting from the top-left corner of the screen), text is +yellow with a red box around it. Both the text and the box have an +opacity of 20%. -The command: @example drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\ x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2" @end example -will draw 'Test Text' with font FreeSerif of size 24 at position x=100 -and y=50 (counting from the top-left corner of the screen), text is -yellow with a red box around it. Both the text and the box have an -opacity of 20%. - Note that the double quotes are not necessary if spaces are not used within the parameter list. +@item +Show the text at the center of the video frame: +@example +drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2" +@end example + +@item +Show a text line sliding from right to left in the last row of the video +frame. The file @file{LONG_LINE} is assumed to contain a single line +with no newlines. +@example +drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t" +@end example + +@item +Show the content of file @file{CREDITS} off the bottom of the frame and scroll up. +@example +drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t" +@end example + +@item +Draw a single green letter "g", at the center of the input video. +The glyph baseline is placed at half screen height. +@example +drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent" +@end example + +@item +Show text for 1 second every 3 seconds: +@example +drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:draw=lt(mod(t\\,3)\\,1):text='blink'" +@end example + +@item +Use fontconfig to set the font. Note that the colons need to be escaped. +@example +drawtext='fontfile=Linux Libertine O-40\\:style=Semibold:text=FFmpeg' +@end example + +@end itemize + For more information about libfreetype, check: @url{http://www.freetype.org/}. +For more information about fontconfig, check: +@url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}. + +@section edgedetect + +Detect and draw edges. The filter uses the Canny Edge Detection algorithm. + +This filter accepts the following optional named parameters: + +@table @option +@item low, high +Set low and high threshold values used by the Canny thresholding +algorithm. + +The high threshold selects the "strong" edge pixels, which are then +connected through 8-connectivity with the "weak" edge pixels selected +by the low threshold. + +@var{low} and @var{high} threshold values must be choosen in the range +[0,1], and @var{low} should be lesser or equal to @var{high}. + +Default value for @var{low} is @code{20/255}, and default value for @var{high} +is @code{50/255}. +@end table + +Example: +@example +edgedetect=low=0.1:high=0.4 +@end example + @section fade Apply fade-in/out effect to input video. It accepts the parameters: -@var{type}:@var{start_frame}:@var{nb_frames} +@var{type}:@var{start_frame}:@var{nb_frames}[:@var{options}] @var{type} specifies if the effect type, can be either "in" for fade-in, or "out" for a fade-out effect. @@ -895,6 +2065,25 @@ effect has to last. At the end of the fade-in effect the output video will have the same intensity as the input video, at the end of the fade-out transition the output video will be completely black. +@var{options} is an optional sequence of @var{key}=@var{value} pairs, +separated by ":". The description of the accepted options follows. + +@table @option + +@item type, t +See @var{type}. + +@item start_frame, s +See @var{start_frame}. + +@item nb_frames, n +See @var{nb_frames}. + +@item alpha +If set to 1, fade only alpha channel, if one exists on the input. +Default value is 0. +@end table + A few usage examples follow, usable too as test scenarios. @example # fade in first 30 frames of video @@ -908,6 +2097,9 @@ fade=in:0:25, fade=out:975:25 # make first 5 frames black, then fade in from frame 5-24 fade=in:5:20 + +# fade in alpha over first 25 frames of video +fade=in:0:25:alpha=1 @end example @section fieldorder @@ -940,7 +2132,7 @@ which is bottom field first. For example: @example -./avconv -i in.vob -vf "fieldorder=bff" out.dv +ffmpeg -i in.vob -vf "fieldorder=bff" out.dv @end example @section fifo @@ -983,13 +2175,20 @@ Desired output framerate. @end table +@section framestep + +Select one frame every N. + +This filter accepts in input a string representing a positive +integer. Default argument is @code{1}. + @anchor{frei0r} @section frei0r Apply a frei0r effect to the input video. To enable compilation of this filter you need to install the frei0r -header and configure Libav with --enable-frei0r. +header and configure FFmpeg with @code{--enable-frei0r}. The filter supports the syntax: @example @@ -1017,27 +2216,37 @@ The number and kind of parameters depend on the loaded effect. If an effect parameter is not specified the default value is set. Some examples follow: + +@itemize +@item +Apply the distort0r effect, set the first two double parameters: @example -# apply the distort0r effect, set the first two double parameters frei0r=distort0r:0.5:0.01 +@end example -# apply the colordistance effect, takes a color as first parameter +@item +Apply the colordistance effect, takes a color as first parameter: +@example frei0r=colordistance:0.2/0.3/0.4 frei0r=colordistance:violet frei0r=colordistance:0x112233 +@end example -# apply the perspective effect, specify the top left and top right -# image positions +@item +Apply the perspective effect, specify the top left and top right image +positions: +@example frei0r=perspective:0.2/0.2:0.8/0.2 @end example +@end itemize For more information see: -@url{http://piksel.org/frei0r} +@url{http://frei0r.dyne.org} @section gradfun Fix the banding artifacts that are sometimes introduced into nearly flat -regions by truncation to 8bit colordepth. +regions by truncation to 8bit color depth. Interpolate the gradients that should go where the bands are, and dither them. @@ -1071,9 +2280,9 @@ gradfun=1.2 Flip the input video horizontally. -For example to horizontally flip the input video with @command{avconv}: +For example to horizontally flip the input video with @command{ffmpeg}: @example -avconv -i in.avi -vf "hflip" out.avi +ffmpeg -i in.avi -vf "hflip" out.avi @end example @section hqdn3d @@ -1103,6 +2312,125 @@ a float number which specifies chroma temporal strength, defaults to @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial} @end table +@section hue + +Modify the hue and/or the saturation of the input. + +This filter accepts the following optional named options: + +@table @option +@item h +Specify the hue angle as a number of degrees. It accepts a float +number or an expression, and defaults to 0.0. + +@item H +Specify the hue angle as a number of degrees. It accepts a float +number or an expression, and defaults to 0.0. + +@item s +Specify the saturation in the [-10,10] range. It accepts a float number and +defaults to 1.0. +@end table + +The @var{h}, @var{H} and @var{s} parameters are expressions containing the +following constants: + +@table @option +@item n +frame count of the input frame starting from 0 + +@item pts +presentation timestamp of the input frame expressed in time base units + +@item r +frame rate of the input video, NAN if the input frame rate is unknown + +@item t +timestamp expressed in seconds, NAN if the input timestamp is unknown + +@item tb +time base of the input video +@end table + +The options can also be set using the syntax: @var{hue}:@var{saturation} + +In this case @var{hue} is expressed in degrees. + +Some examples follow: +@itemize +@item +Set the hue to 90 degrees and the saturation to 1.0: +@example +hue=h=90:s=1 +@end example + +@item +Same command but expressing the hue in radians: +@example +hue=H=PI/2:s=1 +@end example + +@item +Same command without named options, hue must be expressed in degrees: +@example +hue=90:1 +@end example + +@item +Note that "h:s" syntax does not support expressions for the values of +h and s, so the following example will issue an error: +@example +hue=PI/2:1 +@end example + +@item +Rotate hue and make the saturation swing between 0 +and 2 over a period of 1 second: +@example +hue="H=2*PI*t: s=sin(2*PI*t)+1" +@end example + +@item +Apply a 3 seconds saturation fade-in effect starting at 0: +@example +hue="s=min(t/3\,1)" +@end example + +The general fade-in expression can be written as: +@example +hue="s=min(0\, max((t-START)/DURATION\, 1))" +@end example + +@item +Apply a 3 seconds saturation fade-out effect starting at 5 seconds: +@example +hue="s=max(0\, min(1\, (8-t)/3))" +@end example + +The general fade-out expression can be written as: +@example +hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))" +@end example + +@end itemize + +@subsection Commands + +This filter supports the following command: +@table @option +@item reinit +Modify the hue and/or the saturation of the input video. +The command accepts the same named options and syntax than when calling the +filter from the command-line. + +If a parameter is omitted, it is kept at its current value. +@end table + +@section idet + +Interlaceing detect filter. This filter tries to detect if the input is +interlaced or progressive. Top or bottom field first. + @section lut, lutrgb, lutyuv Compute a look-up table for binding each pixel component input value @@ -1148,10 +2476,6 @@ accepts the options: The expressions can contain the following constants and functions: @table @option -@item E, PI, PHI -the corresponding mathematical approximated values for e -(euler number), pi (greek PI), PHI (golden ratio) - @item w, h the input width and height @@ -1197,7 +2521,7 @@ lutrgb="r=negval:g=negval:b=negval" lutyuv="y=negval:u=negval:v=negval" # negate luminance -lutyuv=negval +lutyuv=y=negval # remove chroma components, turns the video into a graytone image lutyuv="u=128:v=128" @@ -1215,6 +2539,90 @@ format=rgba,lutrgb=a="maxval-minval/2" lutyuv=y=gammaval(0.5) @end example +@section mp + +Apply an MPlayer filter to the input video. + +This filter provides a wrapper around most of the filters of +MPlayer/MEncoder. + +This wrapper is considered experimental. Some of the wrapped filters +may not work properly and we may drop support for them, as they will +be implemented natively into FFmpeg. Thus you should avoid +depending on them when writing portable scripts. + +The filters accepts the parameters: +@var{filter_name}[:=]@var{filter_params} + +@var{filter_name} is the name of a supported MPlayer filter, +@var{filter_params} is a string containing the parameters accepted by +the named filter. + +The list of the currently supported filters follows: +@table @var +@item denoise3d +@item detc +@item dint +@item divtc +@item down3dright +@item dsize +@item eq2 +@item eq +@item field +@item fil +@item fixpts +@item fspp +@item geq +@item harddup +@item hqdn3d +@item il +@item ilpack +@item ivtc +@item kerndeint +@item mcdeint +@item noise +@item ow +@item palette +@item perspective +@item phase +@item pp7 +@item pullup +@item qp +@item rectangle +@item sab +@item softpulldown +@item softskip +@item spp +@item telecine +@item tile +@item tinterlace +@item unsharp +@item uspp +@item yuvcsp +@item yvu9 +@end table + +The parameter syntax and behavior for the listed filters are the same +of the corresponding MPlayer filters. For detailed instructions check +the "VIDEO FILTERS" section in the MPlayer manual. + +Some examples follow: +@itemize +@item +Adjust gamma, brightness, contrast: +@example +mp=eq2=1.0:2:0.5 +@end example + +@item +Add temporal noise to input video: +@example +mp=noise=20t +@end example +@end itemize + +See also mplayer(1), @url{http://www.mplayerhq.hu/}. + @section negate Negate input video. @@ -1222,6 +2630,8 @@ Negate input video. This filter accepts an integer in input, if non-zero it negates the alpha component (if available). The default value in input is 0. +@section noformat + Force libavfilter not to use any of the specified pixel formats for the input to the next filter. @@ -1247,7 +2657,7 @@ Pass the video source unchanged to the output. Apply video transform using libopencv. To enable this filter install libopencv library and headers and -configure Libav with --enable-libopencv. +configure FFmpeg with @code{--enable-libopencv}. The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}. @@ -1347,10 +2757,10 @@ Overlay one video on top of another. It takes two inputs and one output, the first input is the "main" video on which the second input is overlayed. -It accepts the parameters: @var{x}:@var{y}. +It accepts the parameters: @var{x}:@var{y}[:@var{options}]. @var{x} is the x coordinate of the overlayed video on the main video, -@var{y} is the y coordinate. The parameters are expressions containing +@var{y} is the y coordinate. @var{x} and @var{y} are expressions containing the following parameters: @table @option @@ -1367,6 +2777,17 @@ overlay input width and height same as @var{overlay_w} and @var{overlay_h} @end table +@var{options} is an optional list of @var{key}=@var{value} pairs, +separated by ":". + +The description of the accepted options follows. + +@table @option +@item rgb +If set to 1, force the filter to accept inputs in the RGB +color space. Default value is 0. +@end table + Be aware that frames are taken from each input video in timestamp order, hence, if their initial timestamps differ, it is a a good idea to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to @@ -1380,16 +2801,23 @@ Follow some examples: overlay=main_w-overlay_w-10:main_h-overlay_h-10 # insert a transparent PNG logo in the bottom left corner of the input -avconv -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output +ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output # insert 2 different transparent PNG logos (second logo on bottom # right corner): -avconv -i input -i logo1 -i logo2 -filter_complex +ffmpeg -i input -i logo1 -i logo2 -filter_complex 'overlay=10:H-h-10,overlay=W-w-10:H-h-10' output # add a transparent color layer on top of the main video, # WxH specifies the size of the main input to the overlay filter color=red@.3:WxH [over]; [in][over] overlay [out] + +# play an original video and a filtered version (here with the deshake filter) +# side by side +ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w' + +# the previous example is the same as: +ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w' @end example You can chain together more overlays but the efficiency of such @@ -1407,10 +2835,6 @@ The parameters @var{width}, @var{height}, @var{x}, and @var{y} are expressions containing the following constants: @table @option -@item E, PI, PHI -the corresponding mathematical approximated values for e -(euler number), pi (greek PI), phi (golden ratio) - @item in_w, in_h the input video width and height @@ -1429,7 +2853,13 @@ x and y offsets as specified by the @var{x} and @var{y} expressions, or NAN if not yet specified @item a -input display aspect ratio, same as @var{iw} / @var{ih} +same as @var{iw} / @var{ih} + +@item sar +input sample aspect ratio + +@item dar +input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar} @item hsub, vsub horizontal and vertical chroma subsample values. For example for the @@ -1469,30 +2899,59 @@ The default value of @var{color} is "black". @end table -Some examples follow: +@section Examples +@itemize +@item +Add paddings with color "violet" to the input video. Output video +size is 640x480, the top-left corner of the input video is placed at +column 0, row 40: @example -# Add paddings with color "violet" to the input video. Output video -# size is 640x480, the top-left corner of the input video is placed at -# column 0, row 40. pad=640:480:0:40:violet +@end example -# pad the input to get an output with dimensions increased bt 3/2, -# and put the input video at the center of the padded area +@item +Pad the input to get an output with dimensions increased by 3/2, +and put the input video at the center of the padded area: +@example pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2" +@end example -# pad the input to get a squared output with size equal to the maximum -# value between the input width and height, and put the input video at -# the center of the padded area +@item +Pad the input to get a squared output with size equal to the maximum +value between the input width and height, and put the input video at +the center of the padded area: +@example pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2" +@end example -# pad the input to get a final w/h ratio of 16:9 +@item +Pad the input to get a final w/h ratio of 16:9: +@example pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2" +@end example -# double output size and put the input video in the bottom-right -# corner of the output padded area +@item +In case of anamorphic video, in order to set the output display aspect +correctly, it is necessary to use @var{sar} in the expression, +according to the relation: +@example +(ih * X / ih) * sar = output_dar +X = output_dar / sar +@end example + +Thus the previous example needs to be modified to: +@example +pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2" +@end example + +@item +Double output size and put the input video in the bottom-right +corner of the output padded area: +@example pad="2*iw:2*ih:ow-iw:oh-ih" @end example +@end itemize @section pixdesctest @@ -1506,18 +2965,43 @@ format=monow, pixdesctest can be used to test the monowhite pixel format descriptor definition. +@section removelogo + +Suppress a TV station logo, using an image file to determine which +pixels comprise the logo. It works by filling in the pixels that +comprise the logo with neighboring pixels. + +This filter requires one argument which specifies the filter bitmap +file, which can be any image format supported by libavformat. The +width and height of the image file must match those of the video +stream being processed. + +Pixels in the provided bitmap image with a value of zero are not +considered part of the logo, non-zero pixels are considered part of +the logo. If you use white (255) for the logo and black (0) for the +rest, you will be safe. For making the filter bitmap, it is +recommended to take a screen capture of a black frame with the logo +visible, and then using a threshold filter followed by the erode +filter once or twice. + +If needed, little splotches can be fixed manually. Remember that if +logo pixels are not covered, the filter quality will be much +reduced. Marking too many pixels as part of the logo does not hurt as +much, but it will increase the amount of blurring needed to cover over +the image and will destroy more information than necessary, and extra +pixels will slow things down on a large logo. + @section scale -Scale the input video to @var{width}:@var{height} and/or convert the image format. +Scale the input video to @var{width}:@var{height}[:@var{interl}=@{1|-1@}] and/or convert the image format. + +The scale filter forces the output display aspect ratio to be the same +of the input, by changing the output sample aspect ratio. The parameters @var{width} and @var{height} are expressions containing the following constants: @table @option -@item E, PI, PHI -the corresponding mathematical approximated values for e -(euler number), pi (greek PI), phi (golden ratio) - @item in_w, in_h the input width and height @@ -1530,12 +3014,15 @@ the output (cropped) width and height @item ow, oh same as @var{out_w} and @var{out_h} -@item dar, a -input display aspect ratio, same as @var{iw} / @var{ih} +@item a +same as @var{iw} / @var{ih} @item sar input sample aspect ratio +@item dar +input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar} + @item hsub, vsub horizontal and vertical chroma subsample values. For example for the pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. @@ -1554,6 +3041,19 @@ ratio of the input image. The default value of @var{width} and @var{height} is 0. +Valid values for the optional parameter @var{interl} are: + +@table @option +@item 1 +force interlaced aware scaling + +@item -1 +select interlaced aware scaling depending on whether the source frames +are flagged as interlaced or not +@end table + +Unless @var{interl} is set to one of the above options, interlaced scaling will not be used. + Some examples follow: @example # scale the input video to a size of 200x100. @@ -1564,6 +3064,9 @@ scale=2*iw:2*ih # the above is the same as scale=2*in_w:2*in_h +# scale the input to 2x with forced interlaced scaling +scale=2*iw:2*ih:interl=1 + # scale the input to half size scale=iw/2:ih/2 @@ -1594,15 +3097,6 @@ is selected and passed to the output, otherwise it is discarded. The expression can contain the following constants: @table @option -@item PI -Greek PI - -@item PHI -golden ratio - -@item E -Euler number - @item n the sequential number of the filtered frame, starting from 0 @@ -1668,6 +3162,12 @@ the frame is bottom-field-first @item pos the position in the file of the filtered frame, -1 if the information is not available (e.g. for synthetic video) + +@item scene +value between 0 and 1 to indicate a new scene; a low value reflects a low +probability for the current frame to introduce a new scene, while a higher +value means the current frame is more likely to be one (see the example below) + @end table The default value of the select expression is "1". @@ -1700,151 +3200,88 @@ select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)' select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)' @end example -@anchor{setdar} -@section setdar - -Set the Display Aspect Ratio for the filter output video. +Complete example to create a mosaic of the first scenes: -This is done by changing the specified Sample (aka Pixel) Aspect -Ratio, according to the following equation: -@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR} - -Keep in mind that this filter does not modify the pixel dimensions of -the video frame. Also the display aspect ratio set by this filter may -be changed by later filters in the filterchain, e.g. in case of -scaling or if another "setdar" or a "setsar" filter is applied. - -The filter accepts a parameter string which represents the wanted -display aspect ratio. -The parameter can be a floating point number string, or an expression -of the form @var{num}:@var{den}, where @var{num} and @var{den} are the -numerator and denominator of the aspect ratio. -If the parameter is not specified, it is assumed the value "0:1". - -For example to change the display aspect ratio to 16:9, specify: @example -setdar=16:9 -# the above is equivalent to -setdar=1.77777 +ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png @end example -See also the @ref{setsar} filter documentation. - -@section setpts - -Change the PTS (presentation timestamp) of the input video frames. - -Accept in input an expression evaluated through the eval API, which -can contain the following constants: - -@table @option -@item PTS -the presentation timestamp in input +Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane +choice. -@item PI -Greek PI +@section setdar, setsar -@item PHI -golden ratio - -@item E -Euler number - -@item N -the count of the input frame, starting from 0. - -@item STARTPTS -the PTS of the first video frame - -@item INTERLACED -tell if the current frame is interlaced - -@item POS -original position in the file of the frame, or undefined if undefined -for the current frame - -@item PREV_INPTS -previous input PTS - -@item PREV_OUTPTS -previous output PTS - -@end table - -Some examples follow: +The @code{setdar} filter sets the Display Aspect Ratio for the filter +output video. +This is done by changing the specified Sample (aka Pixel) Aspect +Ratio, according to the following equation: @example -# start counting PTS from zero -setpts=PTS-STARTPTS - -# fast motion -setpts=0.5*PTS - -# slow motion -setpts=2.0*PTS - -# fixed rate 25 fps -setpts=N/(25*TB) - -# fixed rate 25 fps with some jitter -setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))' +@var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR} @end example -@anchor{setsar} -@section setsar +Keep in mind that the @code{setdar} filter does not modify the pixel +dimensions of the video frame. Also the display aspect ratio set by +this filter may be changed by later filters in the filterchain, +e.g. in case of scaling or if another "setdar" or a "setsar" filter is +applied. -Set the Sample (aka Pixel) Aspect Ratio for the filter output video. +The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for +the filter output video. Note that as a consequence of the application of this filter, the -output display aspect ratio will change according to the following -equation: -@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR} +output display aspect ratio will change according to the equation +above. -Keep in mind that the sample aspect ratio set by this filter may be -changed by later filters in the filterchain, e.g. if another "setsar" -or a "setdar" filter is applied. +Keep in mind that the sample aspect ratio set by the @code{setsar} +filter may be changed by later filters in the filterchain, e.g. if +another "setsar" or a "setdar" filter is applied. -The filter accepts a parameter string which represents the wanted -sample aspect ratio. -The parameter can be a floating point number string, or an expression -of the form @var{num}:@var{den}, where @var{num} and @var{den} are the -numerator and denominator of the aspect ratio. -If the parameter is not specified, it is assumed the value "0:1". +The @code{setdar} and @code{setsar} filters accept a parameter string +which represents the wanted aspect ratio. The parameter can +be a floating point number string, an expression, or a string of the form +@var{num}:@var{den}, where @var{num} and @var{den} are the numerator +and denominator of the aspect ratio. If the parameter is not +specified, it is assumed the value "0:1". -For example to change the sample aspect ratio to 10:11, specify: +For example to change the display aspect ratio to 16:9, specify: @example -setsar=10:11 +setdar=16:9 @end example -@section settb - -Set the timebase to use for the output frames timestamps. -It is mainly useful for testing timebase configuration. +The example above is equivalent to: +@example +setdar=1.77777 +@end example -It accepts in input an arithmetic expression representing a rational. -The expression can contain the constants "PI", "E", "PHI", "AVTB" (the -default timebase), and "intb" (the input timebase). +To change the sample aspect ratio to 10:11, specify: +@example +setsar=10:11 +@end example -The default value for the input is "intb". +@section setfield -Follow some examples. +Force field for the output video frame. -@example -# set the timebase to 1/25 -settb=1/25 +The @code{setfield} filter marks the interlace type field for the +output frames. It does not change the input frame, but only sets the +corresponding property, which affects how the frame is treated by +following filters (e.g. @code{fieldorder} or @code{yadif}). -# set the timebase to 1/10 -settb=0.1 +It accepts a string parameter, which can assume the following values: +@table @samp +@item auto +Keep the same field property. -#set the timebase to 1001/1000 -settb=1+0.001 +@item bff +Mark the frame as bottom-field-first. -#set the timebase to 2*intb -settb=2*intb +@item tff +Mark the frame as top-field-first. -#set the default timebase value -settb=AVTB -@end example +@item prog +Mark the frame as progressive. +@end table @section showinfo @@ -1898,11 +3335,11 @@ the @code{av_get_picture_type_char} function defined in @file{libavutil/avutil.h}. @item checksum -Adler-32 checksum of all the planes of the input frame +Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame @item plane_checksum -Adler-32 checksum of each plane of the input frame, expressed in the form -"[@var{c0} @var{c1} @var{c2} @var{c3}]" +Adler-32 checksum (printed in hexadecimal) of each plane of the input frame, +expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]" @end table @section slicify @@ -1911,7 +3348,7 @@ Pass the images of input video on to next video filter as multiple slices. @example -./avconv -i in.avi -vf "slicify=32" out.avi +ffmpeg -i in.avi -vf "slicify=32" out.avi @end example The filter accepts the slice height as parameter. If the parameter is @@ -1920,6 +3357,35 @@ not specified it will use the default value of 16. Adding this in the beginning of filter chains should make filtering faster due to better use of the memory cache. +@section smartblur + +Blur the input video without impacting the outlines. + +The filter accepts the following parameters: +@var{luma_radius}:@var{luma_strength}:@var{luma_threshold}[:@var{chroma_radius}:@var{chroma_strength}:@var{chroma_threshold}] + +Parameters prefixed by @var{luma} indicate that they work on the +luminance of the pixels whereas parameters prefixed by @var{chroma} +refer to the chrominance of the pixels. + +If the chroma parameters are not set, the luma parameters are used for +either the luminance and the chrominance of the pixels. + +@var{luma_radius} or @var{chroma_radius} must be a float number in the +range [0.1,5.0] that specifies the variance of the gaussian filter +used to blur the image (slower if larger). + +@var{luma_strength} or @var{chroma_strength} must be a float number in +the range [-1.0,1.0] that configures the blurring. A value included in +[0.0,1.0] will blur the image whereas a value included in [-1.0,0.0] +will sharpen the image. + +@var{luma_threshold} or @var{chroma_threshold} must be an integer in +the range [-30,30] that is used as a coefficient to determine whether +a pixel should be blurred or not. A value of 0 will filter all the +image, a value included in [0,30] will filter flat areas and a value +included in [-30,0] will filter edges. + @section split Split input video into several identical outputs. @@ -1929,19 +3395,126 @@ unspecified, it defaults to 2. For example @example -avconv -i INPUT -filter_complex split=5 OUTPUT +ffmpeg -i INPUT -filter_complex split=5 OUTPUT @end example will create 5 copies of the input video. +For example: +@example +[in] split [splitout1][splitout2]; +[splitout1] crop=100:100:0:0 [cropout]; +[splitout2] pad=200:200:100:100 [padout]; +@end example + +will create two separate outputs from the same input, one cropped and +one padded. + +@section super2xsai + +Scale the input by 2x and smooth using the Super2xSaI (Scale and +Interpolate) pixel art scaling algorithm. + +Useful for enlarging pixel art images without reducing sharpness. + +@section swapuv +Swap U & V plane. + +@section thumbnail +Select the most representative frame in a given sequence of consecutive frames. + +It accepts as argument the frames batch size to analyze (default @var{N}=100); +in a set of @var{N} frames, the filter will pick one of them, and then handle +the next batch of @var{N} frames until the end. + +Since the filter keeps track of the whole frames sequence, a bigger @var{N} +value will result in a higher memory usage, so a high value is not recommended. + +The following example extract one picture each 50 frames: +@example +thumbnail=50 +@end example + +Complete example of a thumbnail creation with @command{ffmpeg}: +@example +ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png +@end example + +@section tile + +Tile several successive frames together. + +It accepts as argument the tile size (i.e. the number of lines and columns) +in the form "@var{w}x@var{h}". + +For example, produce 8×8 PNG tiles of all keyframes (@option{-skip_frame +nokey}) in a movie: +@example +ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png +@end example +The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from +duplicating each output frame to accomodate the originally detected frame +rate. + +@section tinterlace + +Perform various types of temporal field interlacing. + +Frames are counted starting from 1, so the first input frame is +considered odd. + +This filter accepts a single parameter specifying the mode. Available +modes are: + +@table @samp +@item merge, 0 +Move odd frames into the upper field, even into the lower field, +generating a double height frame at half framerate. + +@item drop_odd, 1 +Only output even frames, odd frames are dropped, generating a frame with +unchanged height at half framerate. + +@item drop_even, 2 +Only output odd frames, even frames are dropped, generating a frame with +unchanged height at half framerate. + +@item pad, 3 +Expand each frame to full height, but pad alternate lines with black, +generating a frame with double height at the same input framerate. + +@item interleave_top, 4 +Interleave the upper field from odd frames with the lower field from +even frames, generating a frame with unchanged height at half framerate. + +@item interleave_bottom, 5 +Interleave the lower field from odd frames with the upper field from +even frames, generating a frame with unchanged height at half framerate. + +@item interlacex2, 6 +Double frame rate with unchanged height. Frames are inserted each +containing the second temporal field from the previous input frame and +the first temporal field from the next input frame. This mode relies on +the top_field_first flag. Useful for interlaced video displays with no +field synchronisation. +@end table + +Numeric values are deprecated but are accepted for backward +compatibility reasons. + +Default mode is @code{merge}. + @section transpose Transpose rows with columns in the input video and optionally flip it. -It accepts a parameter representing an integer, which can assume the -values: +This filter accepts the following named parameters: + +@table @option +@item dir +Specify the transposition direction. Can assume the following values: @table @samp -@item 0 +@item 0, 4 Rotate by 90 degrees counterclockwise and vertically flip (default), that is: @example L.R L.l @@ -1949,7 +3522,7 @@ L.R L.l l.r R.r @end example -@item 1 +@item 1, 5 Rotate by 90 degrees clockwise, that is: @example L.R l.L @@ -1957,7 +3530,7 @@ L.R l.L l.r r.R @end example -@item 2 +@item 2, 6 Rotate by 90 degrees counterclockwise, that is: @example L.R R.r @@ -1965,7 +3538,7 @@ L.R R.r l.r L.l @end example -@item 3 +@item 3, 7 Rotate by 90 degrees clockwise and vertically flip, that is: @example L.R r.R @@ -1974,6 +3547,25 @@ l.r l.L @end example @end table +For values between 4-7, the transposition is only done if the input +video geometry is portrait and not landscape. These values are +deprecated, the @code{passthrough} option should be used instead. + +@item passthrough +Do not apply the transposition if the input geometry matches the one +specified by the specified value. It accepts the following values: +@table @samp +@item none +Always apply transposition. +@item portrait +Preserve portrait geometry (when @var{height} >= @var{width}). +@item landscape +Preserve landscape geometry (when @var{width} >= @var{height}). +@end table + +Default value is @code{none}. +@end table + @section unsharp Sharpen or blur the input video. @@ -2007,7 +3599,7 @@ and 13, default value is 5. Set the chroma matrix vertical size. It can be an integer between 3 and 13, default value is 5. -@item luma_amount +@item chroma_amount Set the chroma effect strength. It can be a float number between -2.0 and 5.0, default value is 0.0. @@ -2020,8 +3612,8 @@ unsharp=7:7:2.5 # Strong blur of both luma and chroma parameters unsharp=7:7:-2:7:7:-2 -# Use the default values with @command{avconv} -./avconv -i in.avi -vf "unsharp" out.mp4 +# Use the default values with @command{ffmpeg} +ffmpeg -i in.avi -vf "unsharp" out.mp4 @end example @section vflip @@ -2029,7 +3621,7 @@ unsharp=7:7:-2:7:7:-2 Flip the input video vertically. @example -./avconv -i in.avi -vf "vflip" out.avi +ffmpeg -i in.avi -vf "vflip" out.avi @end example @section yadif @@ -2097,35 +3689,37 @@ Buffer video frames, and make them available to the filter chain. This source is mainly intended for a programmatic use, in particular through the interface defined in @file{libavfilter/vsrc_buffer.h}. -It accepts the following parameters: -@var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den} - -All the parameters need to be explicitly defined. - -Follows the list of the accepted parameters. +It accepts a list of options in the form of @var{key}=@var{value} pairs +separated by ":". A description of the accepted options follows. @table @option -@item width, height -Specify the width and height of the buffered video frames. +@item video_size +Specify the size (width and height) of the buffered video frames. -@item pix_fmt_string +@item pix_fmt A string representing the pixel format of the buffered video frames. It may be a number corresponding to a pixel format, or a pixel format name. -@item timebase_num, timebase_den -Specify numerator and denomitor of the timebase assumed by the -timestamps of the buffered frames. +@item time_base +Specify the timebase assumed by the timestamps of the buffered frames. -@item sample_aspect_ratio.num, sample_aspect_ratio.den -Specify numerator and denominator of the sample aspect ratio assumed -by the video frames. +@item time_base +Specify the frame rate expected for the video stream. + +@item pixel_aspect +Specify the sample aspect ratio assumed by the video frames. + +@item sws_param +Specify the optional parameters to be used for the scale filter which +is automatically inserted when an input change is detected in the +input size or format. @end table For example: @example -buffer=320:240:yuv410p:1:24:1:1 +buffer=size=320x240:pix_fmt=yuv410p:time_base=1/24:pixel_aspect=1/1 @end example will instruct the source to accept video frames with size 320x240 and @@ -2135,130 +3729,265 @@ Since the pixel format with name "yuv410p" corresponds to the number 6 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}), this example corresponds to: @example -buffer=320:240:6:1:24 +buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1 @end example -@section color +Alternatively, the options can be specified as a flat string, but this +syntax is deprecated: -Provide an uniformly colored input. +@var{width}:@var{height}:@var{pix_fmt}:@var{time_base.num}:@var{time_base.den}:@var{pixel_aspect.num}:@var{pixel_aspect.den}[:@var{sws_param}] -It accepts the following parameters: -@var{color}:@var{frame_size}:@var{frame_rate} +@section cellauto -Follows the description of the accepted parameters. +Create a pattern generated by an elementary cellular automaton. + +The initial state of the cellular automaton can be defined through the +@option{filename}, and @option{pattern} options. If such options are +not specified an initial state is created randomly. + +At each new frame a new row in the video is filled with the result of +the cellular automaton next generation. The behavior when the whole +frame is filled is defined by the @option{scroll} option. + +This source accepts a list of options in the form of +@var{key}=@var{value} pairs separated by ":". A description of the +accepted options follows. @table @option +@item filename, f +Read the initial cellular automaton state, i.e. the starting row, from +the specified file. +In the file, each non-whitespace character is considered an alive +cell, a newline will terminate the row, and further characters in the +file will be ignored. -@item color -Specify the color of the source. It can be the name of a color (case -insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an -alpha specifier. The default value is "black". +@item pattern, p +Read the initial cellular automaton state, i.e. the starting row, from +the specified string. -@item frame_size -Specify the size of the sourced video, it may be a string of the form -@var{width}x@var{height}, or the name of a size abbreviation. The -default value is "320x240". +Each non-whitespace character in the string is considered an alive +cell, a newline will terminate the row, and further characters in the +string will be ignored. -@item frame_rate -Specify the frame rate of the sourced video, as the number of frames -generated per second. It has to be a string in the format -@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float -number or a valid video frame rate abbreviation. The default value is -"25". +@item rate, r +Set the video rate, that is the number of frames generated per second. +Default is 25. + +@item random_fill_ratio, ratio +Set the random fill ratio for the initial cellular automaton row. It +is a floating point number value ranging from 0 to 1, defaults to +1/PHI. + +This option is ignored when a file or a pattern is specified. + +@item random_seed, seed +Set the seed for filling randomly the initial row, must be an integer +included between 0 and UINT32_MAX. If not specified, or if explicitly +set to -1, the filter will try to use a good random seed on a best +effort basis. + +@item rule +Set the cellular automaton rule, it is a number ranging from 0 to 255. +Default value is 110. + +@item size, s +Set the size of the output video. + +If @option{filename} or @option{pattern} is specified, the size is set +by default to the width of the specified initial state row, and the +height is set to @var{width} * PHI. + +If @option{size} is set, it must contain the width of the specified +pattern string, and the specified pattern will be centered in the +larger row. + +If a filename or a pattern string is not specified, the size value +defaults to "320x518" (used for a randomly generated initial state). + +@item scroll +If set to 1, scroll the output upward when all the rows in the output +have been already filled. If set to 0, the new generated row will be +written over the top row just after the bottom row is filled. +Defaults to 1. + +@item start_full, full +If set to 1, completely fill the output with generated rows before +outputting the first frame. +This is the default behavior, for disabling set the value to 0. +@item stitch +If set to 1, stitch the left and right row edges together. +This is the default behavior, for disabling set the value to 0. @end table -For example the following graph description will generate a red source -with an opacity of 0.2, with size "qcif" and a frame rate of 10 -frames per second, which will be overlayed over the source connected -to the pad with identifier "in". +@subsection Examples +@itemize +@item +Read the initial state from @file{pattern}, and specify an output of +size 200x400. @example -"color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]" +cellauto=f=pattern:s=200x400 @end example -@section movie +@item +Generate a random initial row with a width of 200 cells, with a fill +ratio of 2/3: +@example +cellauto=ratio=2/3:s=200x200 +@end example + +@item +Create a pattern generated by rule 18 starting by a single alive cell +centered on an initial row with width 100: +@example +cellauto=p=@@:s=100x400:full=0:rule=18 +@end example -Read a video stream from a movie container. +@item +Specify a more elaborated initial pattern: +@example +cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18 +@end example -Note that this source is a hack that bypasses the standard input path. It can be -useful in applications that do not support arbitrary filter graphs, but its use -is discouraged in those that do. Specifically in @command{avconv} this filter -should never be used, the @option{-filter_complex} option fully replaces it. +@end itemize -It accepts the syntax: @var{movie_name}[:@var{options}] where -@var{movie_name} is the name of the resource to read (not necessarily -a file but also a device or a stream accessed through some protocol), -and @var{options} is an optional sequence of @var{key}=@var{value} -pairs, separated by ":". +@section mandelbrot -The description of the accepted options follows. +Generate a Mandelbrot set fractal, and progressively zoom towards the +point specified with @var{start_x} and @var{start_y}. + +This source accepts a list of options in the form of +@var{key}=@var{value} pairs separated by ":". A description of the +accepted options follows. @table @option -@item format_name, f -Specifies the format assumed for the movie to read, and can be either -the name of a container or an input device. If not specified the -format is guessed from @var{movie_name} or by probing. +@item end_pts +Set the terminal pts value. Default value is 400. -@item seek_point, sp -Specifies the seek point in seconds, the frames will be output -starting from this seek point, the parameter is evaluated with -@code{av_strtod} so the numerical value may be suffixed by an IS -postfix. Default value is "0". +@item end_scale +Set the terminal scale value. +Must be a floating point value. Default value is 0.3. -@item stream_index, si -Specifies the index of the video stream to read. If the value is -1, -the best suited video stream will be automatically selected. Default -value is "-1". +@item inner +Set the inner coloring mode, that is the algorithm used to draw the +Mandelbrot fractal internal region. +It shall assume one of the following values: +@table @option +@item black +Set black mode. +@item convergence +Show time until convergence. +@item mincol +Set color based on point closest to the origin of the iterations. +@item period +Set period mode. @end table -This filter allows to overlay a second video on top of main input of -a filtergraph as shown in this graph: -@example -input -----------> deltapts0 --> overlay --> output - ^ - | -movie --> scale--> deltapts1 -------+ -@end example +Default value is @var{mincol}. -Some examples follow: -@example -# skip 3.2 seconds from the start of the avi file in.avi, and overlay it -# on top of the input labelled as "in". -movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie]; -[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out] +@item bailout +Set the bailout value. Default value is 10.0. -# read from a video4linux2 device, and overlay it on top of the input -# labelled as "in" -movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie]; -[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out] +@item maxiter +Set the maximum of iterations performed by the rendering +algorithm. Default value is 7189. + +@item outer +Set outer coloring mode. +It shall assume one of following values: +@table @option +@item iteration_count +Set iteration cound mode. +@item normalized_iteration_count +set normalized iteration count mode. +@end table +Default value is @var{normalized_iteration_count}. + +@item rate, r +Set frame rate, expressed as number of frames per second. Default +value is "25". + +@item size, s +Set frame size. Default value is "640x480". + +@item start_scale +Set the initial scale value. Default value is 3.0. +@item start_x +Set the initial x position. Must be a floating point value between +-100 and 100. Default value is -0.743643887037158704752191506114774. + +@item start_y +Set the initial y position. Must be a floating point value between +-100 and 100. Default value is -0.131825904205311970493132056385139. +@end table + +@section mptestsrc + +Generate various test patterns, as generated by the MPlayer test filter. + +The size of the generated video is fixed, and is 256x256. +This source is useful in particular for testing encoding features. + +This source accepts an optional sequence of @var{key}=@var{value} pairs, +separated by ":". The description of the accepted options follows. + +@table @option + +@item rate, r +Specify the frame rate of the sourced video, as the number of frames +generated per second. It has to be a string in the format +@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float +number or a valid video frame rate abbreviation. The default value is +"25". + +@item duration, d +Set the video duration of the sourced video. The accepted syntax is: +@example +[-]HH:MM:SS[.m...] +[-]S+[.m...] @end example +See also the function @code{av_parse_time()}. + +If not specified, or the expressed duration is negative, the video is +supposed to be generated forever. -@section nullsrc +@item test, t -Null video source, never return images. It is mainly useful as a -template and to be employed in analysis / debugging tools. +Set the number or the name of the test to perform. Supported tests are: +@table @option +@item dc_luma +@item dc_chroma +@item freq_luma +@item freq_chroma +@item amp_luma +@item amp_chroma +@item cbp +@item mv +@item ring1 +@item ring2 +@item all +@end table -It accepts as optional parameter a string of the form -@var{width}:@var{height}:@var{timebase}. +Default value is "all", which will cycle through the list of all tests. +@end table -@var{width} and @var{height} specify the size of the configured -source. The default values of @var{width} and @var{height} are -respectively 352 and 288 (corresponding to the CIF size format). +For example the following: +@example +testsrc=t=dc_luma +@end example -@var{timebase} specifies an arithmetic expression representing a -timebase. The expression can contain the constants "PI", "E", "PHI", -"AVTB" (the default timebase), and defaults to the value "AVTB". +will generate a "dc_luma" test pattern. @section frei0r_src Provide a frei0r source. To enable compilation of this filter you need to install the frei0r -header and configure Libav with --enable-frei0r. +header and configure FFmpeg with @code{--enable-frei0r}. The source supports the syntax: @example @@ -2273,28 +4002,169 @@ the form @var{num}/@var{den} or a frame rate abbreviation. information regarding frei0r and how to set the parameters read the section @ref{frei0r} in the description of the video filters. -Some examples follow: +For example, to generate a frei0r partik0l source with size 200x200 +and frame rate 10 which is overlayed on the overlay filter main input: @example -# generate a frei0r partik0l source with size 200x200 and framerate 10 -# which is overlayed on the overlay filter main input frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay @end example -@section rgbtestsrc, testsrc +@section life + +Generate a life pattern. + +This source is based on a generalization of John Conway's life game. + +The sourced input represents a life grid, each pixel represents a cell +which can be in one of two possible states, alive or dead. Every cell +interacts with its eight neighbours, which are the cells that are +horizontally, vertically, or diagonally adjacent. + +At each interaction the grid evolves according to the adopted rule, +which specifies the number of neighbor alive cells which will make a +cell stay alive or born. The @option{rule} option allows to specify +the rule to adopt. + +This source accepts a list of options in the form of +@var{key}=@var{value} pairs separated by ":". A description of the +accepted options follows. + +@table @option +@item filename, f +Set the file from which to read the initial grid state. In the file, +each non-whitespace character is considered an alive cell, and newline +is used to delimit the end of each row. + +If this option is not specified, the initial grid is generated +randomly. + +@item rate, r +Set the video rate, that is the number of frames generated per second. +Default is 25. + +@item random_fill_ratio, ratio +Set the random fill ratio for the initial random grid. It is a +floating point number value ranging from 0 to 1, defaults to 1/PHI. +It is ignored when a file is specified. + +@item random_seed, seed +Set the seed for filling the initial random grid, must be an integer +included between 0 and UINT32_MAX. If not specified, or if explicitly +set to -1, the filter will try to use a good random seed on a best +effort basis. + +@item rule +Set the life rule. + +A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}", +where @var{NS} and @var{NB} are sequences of numbers in the range 0-8, +@var{NS} specifies the number of alive neighbor cells which make a +live cell stay alive, and @var{NB} the number of alive neighbor cells +which make a dead cell to become alive (i.e. to "born"). +"s" and "b" can be used in place of "S" and "B", respectively. + +Alternatively a rule can be specified by an 18-bits integer. The 9 +high order bits are used to encode the next cell state if it is alive +for each number of neighbor alive cells, the low order bits specify +the rule for "borning" new cells. Higher order bits encode for an +higher number of neighbor cells. +For example the number 6153 = @code{(12<<9)+9} specifies a stay alive +rule of 12 and a born rule of 9, which corresponds to "S23/B03". + +Default value is "S23/B3", which is the original Conway's game of life +rule, and will keep a cell alive if it has 2 or 3 neighbor alive +cells, and will born a new cell if there are three alive cells around +a dead cell. + +@item size, s +Set the size of the output video. + +If @option{filename} is specified, the size is set by default to the +same size of the input file. If @option{size} is set, it must contain +the size specified in the input file, and the initial grid defined in +that file is centered in the larger resulting area. + +If a filename is not specified, the size value defaults to "320x240" +(used for a randomly generated initial grid). + +@item stitch +If set to 1, stitch the left and right grid edges together, and the +top and bottom edges also. Defaults to 1. + +@item mold +Set cell mold speed. If set, a dead cell will go from @option{death_color} to +@option{mold_color} with a step of @option{mold}. @option{mold} can have a +value from 0 to 255. + +@item life_color +Set the color of living (or new born) cells. + +@item death_color +Set the color of dead cells. If @option{mold} is set, this is the first color +used to represent a dead cell. + +@item mold_color +Set mold color, for definitely dead and moldy cells. +@end table + +@subsection Examples + +@itemize +@item +Read a grid from @file{pattern}, and center it on a grid of size +300x300 pixels: +@example +life=f=pattern:s=300x300 +@end example + +@item +Generate a random grid of size 200x200, with a fill ratio of 2/3: +@example +life=ratio=2/3:s=200x200 +@end example + +@item +Specify a custom rule for evolving a randomly generated grid: +@example +life=rule=S14/B34 +@end example + +@item +Full example with slow death effect (mold) using @command{ffplay}: +@example +ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16 +@end example +@end itemize + +@section color, nullsrc, rgbtestsrc, smptebars, testsrc + +The @code{color} source provides an uniformly colored input. + +The @code{nullsrc} source returns unprocessed video frames. It is +mainly useful to be employed in analysis / debugging tools, or as the +source for filters which ignore the input data. The @code{rgbtestsrc} source generates an RGB test pattern useful for detecting RGB vs BGR issues. You should see a red, green and blue stripe from top to bottom. +The @code{smptebars} source generates a color bars pattern, based on +the SMPTE Engineering Guideline EG 1-1990. + The @code{testsrc} source generates a test video pattern, showing a color pattern, a scrolling gradient and a timestamp. This is mainly intended for testing purposes. -Both sources accept an optional sequence of @var{key}=@var{value} pairs, +These sources accept an optional sequence of @var{key}=@var{value} pairs, separated by ":". The description of the accepted options follows. @table @option +@item color, c +Specify the color of the source, only used in the @code{color} +source. It can be the name of a color (case insensitive match) or a +0xRRGGBB[AA] sequence, possibly followed by an alpha specifier. The +default value is "black". + @item size, s Specify the size of the sourced video, it may be a string of the form @var{width}x@var{height}, or the name of a size abbreviation. The @@ -2310,7 +4180,7 @@ number or a valid video frame rate abbreviation. The default value is @item sar Set the sample aspect ratio of the sourced video. -@item duration +@item duration, d Set the video duration of the sourced video. The accepted syntax is: @example [-]HH[:MM[:SS[.m...]]] @@ -2320,6 +4190,14 @@ See also the function @code{av_parse_time()}. If not specified, or the expressed duration is negative, the video is supposed to be generated forever. + +@item decimals, n +Set the number of decimals to show in the timestamp, only used in the +@code{testsrc} source. + +The displayed timestamp value will correspond to the original +timestamp value multiplied by the power of 10 of the specified +value. Default value is 0. @end table For example the following: @@ -2328,7 +4206,21 @@ testsrc=duration=5.3:size=qcif:rate=10 @end example will generate a video with a duration of 5.3 seconds, with size -176x144 and a framerate of 10 frames per second. +176x144 and a frame rate of 10 frames per second. + +The following graph description will generate a red source +with an opacity of 0.2, with size "qcif" and a frame rate of 10 +frames per second. +@example +color=c=red@@0.2:s=qcif:r=10 +@end example + +If the input content is to be ignored, @code{nullsrc} can be used. The +following command generates noise in the luminance plane by employing +the @code{mp=geq} filter: +@example +nullsrc=s=256x256, mp=geq=random(1)*255:128:128 +@end example @c man end VIDEO SOURCES @@ -2342,8 +4234,13 @@ Below is a description of the currently available video sinks. Buffer video frames, and make them available to the end of the filter graph. -This sink is intended for a programmatic use through the interface defined in -@file{libavfilter/buffersink.h}. +This sink is mainly intended for a programmatic use, in particular +through the interface defined in @file{libavfilter/buffersink.h}. + +It does not require a string parameter in input, but you need to +specify a pointer to a list of supported pixel formats terminated by +-1 in the opaque parameter provided to @code{avfilter_init_filter} +when initializing this sink. @section nullsink @@ -2352,3 +4249,560 @@ mainly useful as a template and to be employed in analysis / debugging tools. @c man end VIDEO SINKS + +@chapter Multimedia Filters +@c man begin MULTIMEDIA FILTERS + +Below is a description of the currently available multimedia filters. + +@section asendcmd, sendcmd + +Send commands to filters in the filtergraph. + +These filters read commands to be sent to other filters in the +filtergraph. + +@code{asendcmd} must be inserted between two audio filters, +@code{sendcmd} must be inserted between two video filters, but apart +from that they act the same way. + +The specification of commands can be provided in the filter arguments +with the @var{commands} option, or in a file specified by the +@var{filename} option. + +These filters accept the following options: +@table @option +@item commands, c +Set the commands to be read and sent to the other filters. +@item filename, f +Set the filename of the commands to be read and sent to the other +filters. +@end table + +@subsection Commands syntax + +A commands description consists of a sequence of interval +specifications, comprising a list of commands to be executed when a +particular event related to that interval occurs. The occurring event +is typically the current frame time entering or leaving a given time +interval. + +An interval is specified by the following syntax: +@example +@var{START}[-@var{END}] @var{COMMANDS}; +@end example + +The time interval is specified by the @var{START} and @var{END} times. +@var{END} is optional and defaults to the maximum time. + +The current frame time is considered within the specified interval if +it is included in the interval [@var{START}, @var{END}), that is when +the time is greater or equal to @var{START} and is lesser than +@var{END}. + +@var{COMMANDS} consists of a sequence of one or more command +specifications, separated by ",", relating to that interval. The +syntax of a command specification is given by: +@example +[@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG} +@end example + +@var{FLAGS} is optional and specifies the type of events relating to +the time interval which enable sending the specified command, and must +be a non-null sequence of identifier flags separated by "+" or "|" and +enclosed between "[" and "]". + +The following flags are recognized: +@table @option +@item enter +The command is sent when the current frame timestamp enters the +specified interval. In other words, the command is sent when the +previous frame timestamp was not in the given interval, and the +current is. + +@item leave +The command is sent when the current frame timestamp leaves the +specified interval. In other words, the command is sent when the +previous frame timestamp was in the given interval, and the +current is not. +@end table + +If @var{FLAGS} is not specified, a default value of @code{[enter]} is +assumed. + +@var{TARGET} specifies the target of the command, usually the name of +the filter class or a specific filter instance name. + +@var{COMMAND} specifies the name of the command for the target filter. + +@var{ARG} is optional and specifies the optional list of argument for +the given @var{COMMAND}. + +Between one interval specification and another, whitespaces, or +sequences of characters starting with @code{#} until the end of line, +are ignored and can be used to annotate comments. + +A simplified BNF description of the commands specification syntax +follows: +@example +@var{COMMAND_FLAG} ::= "enter" | "leave" +@var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}] +@var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}] +@var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}] +@var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS} +@var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}] +@end example + +@subsection Examples + +@itemize +@item +Specify audio tempo change at second 4: +@example +asendcmd=c='4.0 atempo tempo 1.5',atempo +@end example + +@item +Specify a list of drawtext and hue commands in a file. +@example +# show text in the interval 5-10 +5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world', + [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text='; + +# desaturate the image in the interval 15-20 +15.0-20.0 [enter] hue reinit s=0, + [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor', + [leave] hue reinit s=1, + [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color'; + +# apply an exponential saturation fade-out effect, starting from time 25 +25 [enter] hue s=exp(t-25) +@end example + +A filtergraph allowing to read and process the above command list +stored in a file @file{test.cmd}, can be specified with: +@example +sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue +@end example +@end itemize + +@section asetpts, setpts + +Change the PTS (presentation timestamp) of the input frames. + +@code{asetpts} works on audio frames, @code{setpts} on video frames. + +Accept in input an expression evaluated through the eval API, which +can contain the following constants: + +@table @option +@item FRAME_RATE +frame rate, only defined for constant frame-rate video + +@item PTS +the presentation timestamp in input + +@item N +the count of the input frame, starting from 0. + +@item NB_CONSUMED_SAMPLES +the number of consumed samples, not including the current frame (only +audio) + +@item NB_SAMPLES +the number of samples in the current frame (only audio) + +@item SAMPLE_RATE +audio sample rate + +@item STARTPTS +the PTS of the first frame + +@item STARTT +the time in seconds of the first frame + +@item INTERLACED +tell if the current frame is interlaced + +@item T +the time in seconds of the current frame + +@item TB +the time base + +@item POS +original position in the file of the frame, or undefined if undefined +for the current frame + +@item PREV_INPTS +previous input PTS + +@item PREV_INT +previous input time in seconds + +@item PREV_OUTPTS +previous output PTS + +@item PREV_OUTT +previous output time in seconds +@end table + +@subsection Examples + +@itemize +@item +Start counting PTS from zero +@example +setpts=PTS-STARTPTS +@end example + +@item +Apply fast motion effect: +@example +setpts=0.5*PTS +@end example + +@item +Apply slow motion effect: +@example +setpts=2.0*PTS +@end example + +@item +Set fixed rate of 25 frames per second: +@example +setpts=N/(25*TB) +@end example + +@item +Set fixed rate 25 fps with some jitter: +@example +setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))' +@end example + +@item +Apply an offset of 10 seconds to the input PTS: +@example +setpts=PTS+10/TB +@end example +@end itemize + +@section ebur128 + +EBU R128 scanner filter. This filter takes an audio stream as input and outputs +it unchanged. By default, it logs a message at a frequency of 10Hz with the +Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}), +Integrated loudness (@code{I}) and Loudness Range (@code{LRA}). + +The filter also has a video output (see the @var{video} option) with a real +time graph to observe the loudness evolution. The graphic contains the logged +message mentioned above, so it is not printed anymore when this option is set, +unless the verbose logging is set. The main graphing area contains the +short-term loudness (3 seconds of analysis), and the gauge on the right is for +the momentary loudness (400 milliseconds). + +More information about the Loudness Recommendation EBU R128 on +@url{http://tech.ebu.ch/loudness}. + +The filter accepts the following named parameters: + +@table @option + +@item video +Activate the video output. The audio stream is passed unchanged whether this +option is set or no. The video stream will be the first output stream if +activated. Default is @code{0}. + +@item size +Set the video size. This option is for video only. Default and minimum +resolution is @code{640x480}. + +@item meter +Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and +@code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any +other integer value between this range is allowed. + +@end table + +Example of real-time graph using @command{ffplay}, with a EBU scale meter +18: +@example +ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]" +@end example + +Run an analysis with @command{ffmpeg}: +@example +ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null - +@end example + +@section settb, asettb + +Set the timebase to use for the output frames timestamps. +It is mainly useful for testing timebase configuration. + +It accepts in input an arithmetic expression representing a rational. +The expression can contain the constants "AVTB" (the +default timebase), "intb" (the input timebase) and "sr" (the sample rate, +audio only). + +The default value for the input is "intb". + +@subsection Examples + +@itemize +@item +Set the timebase to 1/25: +@example +settb=1/25 +@end example + +@item +Set the timebase to 1/10: +@example +settb=0.1 +@end example + +@item +Set the timebase to 1001/1000: +@example +settb=1+0.001 +@end example + +@item +Set the timebase to 2*intb: +@example +settb=2*intb +@end example + +@item +Set the default timebase value: +@example +settb=AVTB +@end example +@end itemize + +@section concat + +Concatenate audio and video streams, joining them together one after the +other. + +The filter works on segments of synchronized video and audio streams. All +segments must have the same number of streams of each type, and that will +also be the number of streams at output. + +The filter accepts the following named parameters: +@table @option + +@item n +Set the number of segments. Default is 2. + +@item v +Set the number of output video streams, that is also the number of video +streams in each segment. Default is 1. + +@item a +Set the number of output audio streams, that is also the number of video +streams in each segment. Default is 0. + +@end table + +The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then +@var{a} audio outputs. + +There are @var{n}×(@var{v}+@var{a}) inputs: first the inputs for the first +segment, in the same order as the outputs, then the inputs for the second +segment, etc. + +Related streams do not always have exactly the same duration, for various +reasons including codec frame size or sloppy authoring. For that reason, +related synchronized streams (e.g. a video and its audio track) should be +concatenated at once. The concat filter will use the duration of the longest +stream in each segment (except the last one), and if necessary pad shorter +audio streams with silence. + +For this filter to work correctly, all segments must start at timestamp 0. + +All corresponding streams must have the same parameters in all segments; the +filtering system will automatically select a common pixel format for video +streams, and a common sample format, sample rate and channel layout for +audio streams, but other settings, such as resolution, must be converted +explicitly by the user. + +Different frame rates are acceptable but will result in variable frame rate +at output; be sure to configure the output file to handle it. + +Examples: +@itemize +@item +Concatenate an opening, an episode and an ending, all in bilingual version +(video in stream 0, audio in streams 1 and 2): +@example +ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \ + '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2] + concat=n=3:v=1:a=2 [v] [a1] [a2]' \ + -map '[v]' -map '[a1]' -map '[a2]' output.mkv +@end example + +@item +Concatenate two parts, handling audio and video separately, using the +(a)movie sources, and adjusting the resolution: +@example +movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ; +movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ; +[v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa] +@end example +Note that a desync will happen at the stitch if the audio and video streams +do not have exactly the same duration in the first file. + +@end itemize + +@section showspectrum + +Convert input audio to a video output, representing the audio frequency +spectrum. + +The filter accepts the following named parameters: +@table @option +@item size, s +Specify the video size for the output. Default value is @code{640x480}. +@end table + +The usage is very similar to the showwaves filter; see the examples in that +section. + +@section showwaves + +Convert input audio to a video output, representing the samples waves. + +The filter accepts the following named parameters: +@table @option + +@item n +Set the number of samples which are printed on the same column. A +larger value will decrease the frame rate. Must be a positive +integer. This option can be set only if the value for @var{rate} +is not explicitly specified. + +@item rate, r +Set the (approximate) output frame rate. This is done by setting the +option @var{n}. Default value is "25". + +@item size, s +Specify the video size for the output. Default value is "600x240". +@end table + +Some examples follow. +@itemize +@item +Output the input file audio and the corresponding video representation +at the same time: +@example +amovie=a.mp3,asplit[out0],showwaves[out1] +@end example + +@item +Create a synthetic signal and show it with showwaves, forcing a +framerate of 30 frames per second: +@example +aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1] +@end example +@end itemize + +@c man end MULTIMEDIA FILTERS + +@chapter Multimedia Sources +@c man begin MULTIMEDIA SOURCES + +Below is a description of the currently available multimedia sources. + +@section amovie + +This is the same as @ref{src_movie} source, except it selects an audio +stream by default. + +@anchor{src_movie} +@section movie + +Read audio and/or video stream(s) from a movie container. + +It accepts the syntax: @var{movie_name}[:@var{options}] where +@var{movie_name} is the name of the resource to read (not necessarily +a file but also a device or a stream accessed through some protocol), +and @var{options} is an optional sequence of @var{key}=@var{value} +pairs, separated by ":". + +The description of the accepted options follows. + +@table @option + +@item format_name, f +Specifies the format assumed for the movie to read, and can be either +the name of a container or an input device. If not specified the +format is guessed from @var{movie_name} or by probing. + +@item seek_point, sp +Specifies the seek point in seconds, the frames will be output +starting from this seek point, the parameter is evaluated with +@code{av_strtod} so the numerical value may be suffixed by an IS +postfix. Default value is "0". + +@item streams, s +Specifies the streams to read. Several streams can be specified, separated +by "+". The source will then have as many outputs, in the same order. The +syntax is explained in the @ref{Stream specifiers} chapter. Two special +names, "dv" and "da" specify respectively the default (best suited) video +and audio stream. Default is "dv", or "da" if the filter is called as +"amovie". + +@item stream_index, si +Specifies the index of the video stream to read. If the value is -1, +the best suited video stream will be automatically selected. Default +value is "-1". Deprecated. If the filter is called "amovie", it will select +audio instead of video. + +@item loop +Specifies how many times to read the stream in sequence. +If the value is less than 1, the stream will be read again and again. +Default value is "1". + +Note that when the movie is looped the source timestamps are not +changed, so it will generate non monotonically increasing timestamps. +@end table + +This filter allows to overlay a second video on top of main input of +a filtergraph as shown in this graph: +@example +input -----------> deltapts0 --> overlay --> output + ^ + | +movie --> scale--> deltapts1 -------+ +@end example + +Some examples follow. + +@itemize +@item +Skip 3.2 seconds from the start of the avi file in.avi, and overlay it +on top of the input labelled as "in": +@example +movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie]; +[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out] +@end example + +@item +Read from a video4linux2 device, and overlay it on top of the input +labelled as "in": +@example +movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie]; +[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out] +@end example + +@item +Read the first video stream and the audio stream with id 0x81 from +dvd.vob; the video is connected to the pad named "video" and the audio is +connected to the pad named "audio": +@example +movie=dvd.vob:s=v:0+#0x81 [video] [audio] +@end example +@end itemize + +@c man end MULTIMEDIA SOURCES |
