diff options
author | Paul B Mahol <onemda@gmail.com> | 2015-09-17 12:38:23 +0300 |
---|---|---|
committer | Paul B Mahol <onemda@gmail.com> | 2015-09-22 23:07:36 +0300 |
commit | ed4257de2d74ce5e5ae77ae96d58c58f1bbaeacd (patch) | |
tree | 0f2f957ccf4856bcbc1d1a6c1553f28a6f1dad1f /doc | |
parent | 31623e9d1ea960035cee59839e016397a559dab3 (diff) |
avfilter: add agate filter
Signed-off-by: Paul B Mahol <onemda@gmail.com>
Diffstat (limited to 'doc')
-rw-r--r-- | doc/filters.texi | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/doc/filters.texi b/doc/filters.texi index 5bbbaf0b78..5b00eca19f 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -641,6 +641,57 @@ Force the output to either unsigned 8-bit or signed 16-bit stereo aformat=sample_fmts=u8|s16:channel_layouts=stereo @end example +@section agate + +A gate is mainly used to reduce lower parts of a signal. This kind of signal +processing reduces disturbing noise between useful signals. + +Gating is done by detecting the volume below a chosen level @var{threshold} +and divide it by the factor set with @var{ratio}. The bottom of the noise +floor is set via @var{range}. Because an exact manipulation of the signal +would cause distortion of the waveform the reduction can be levelled over +time. This is done by setting @var{attack} and @var{release}. + +@var{attack} determines how long the signal has to fall below the threshold +before any reduction will occur and @var{release} sets the time the signal +has to raise above the threshold to reduce the reduction again. +Shorter signals than the chosen attack time will be left untouched. + +@table @option +@item level_in +Set input level before filtering. + +@item range +Set the level of gain reduction when the signal is below the threshold. + +@item threshold +If a signal rises above this level the gain reduction is released. + +@item ratio +Set a ratio about which the signal is reduced. + +@item attack +Amount of milliseconds the signal has to rise above the threshold before gain +reduction stops. + +@item release +Amount of milliseconds the signal has to fall below the threshold before the +reduction is increased again. + +@item makeup +Set amount of amplification of signal after processing. + +@item knee +Curve the sharp knee around the threshold to enter gain reduction more softly. + +@item detection +Choose if exact signal should be taken for detection or an RMS like one. + +@item link +Choose if the average level between all channels or the louder channel affects +the reduction. +@end table + @section alimiter The limiter prevents input signal from raising over a desired threshold. |