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authorClément Bœsch <ubitux@gmail.com>2012-01-03 23:47:09 +0100
committerClément Bœsch <ubitux@gmail.com>2012-01-08 17:08:55 +0100
commit0c01947316eaaa46946f9e93218fe5ab115df905 (patch)
tree49ac9a6d7fbad6915b702866314db537f7d0466f /doc
parent5ccdb907c120cbd7f58d09cd523ba39fce8608b2 (diff)
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lavfi: add audio silencedetect filter.
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@@ -358,6 +358,36 @@ 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.
+@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.
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