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diff --git a/doc/filters.texi b/doc/filters.texi index ada992e..798d04b 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -267,6 +267,36 @@ See the ``Quoting and escaping'' section in the ffmpeg-utils manual for more information about the escaping and quoting rules adopted by FFmpeg. +@chapter Timeline editing + +Some filters support a generic @option{enable} option. For the filters +supporting timeline editing, this option can be set to an expression which is +evaluated before sending a frame to the filter. If the evaluation is non-zero, +the filter will be enabled, otherwise the frame will be sent unchanged to the +next filter in the filtergraph. + +The expression accepts the following values: +@table @samp +@item t +timestamp expressed in seconds, NAN if the input timestamp is unknown + +@item n +sequential number of the input frame, starting from 0 + +@item pos +the position in the file of the input frame, NAN if unknown +@end table + +Like any other filtering option, the @option{enable} option follows the same +rules. + +For example, to enable a denoiser filter (@ref{hqdn3d}) from 10 seconds to 3 +minutes, and a @ref{curves} filter starting at 3 seconds: +@example +hqdn3d = enable='between(t,10,3*60)', +curves = enable='gte(t,3)' : preset=cross_process +@end example + @c man end FILTERGRAPH DESCRIPTION @chapter Audio Filters @@ -2409,6 +2439,7 @@ indicates never reset and return the largest area encountered during playback. @end table +@anchor{curves} @section curves Apply color adjustments using curves. @@ -4013,6 +4044,7 @@ ffplay -i input -vf histogram @end itemize +@anchor{hqdn3d} @section hqdn3d High precision/quality 3d denoise filter. This filter aims to reduce |