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| author | Paul B Mahol <onemda@gmail.com> | 2020-05-02 20:27:37 +0200 |
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| committer | Paul B Mahol <onemda@gmail.com> | 2020-11-15 12:59:40 +0100 |
| commit | 9f20e5d2819eec8dcdb8efb6cf92bc39d362e78f (patch) | |
| tree | baf8f62b87f48e922fe5c16e86470337872c1b76 /doc/filters.texi | |
| parent | 46e362b76551d6587747e6a41e97b1673df2ada9 (diff) | |
| download | ffmpeg-9f20e5d2819eec8dcdb8efb6cf92bc39d362e78f.tar.gz | |
avfilter: add speechnorm filter
Diffstat (limited to 'doc/filters.texi')
| -rw-r--r-- | doc/filters.texi | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/doc/filters.texi b/doc/filters.texi index 8380f6cac2..8c9eccb00e 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -5276,6 +5276,69 @@ and also with custom gain: @end example @end itemize +@section speechnorm +Speech Normalizer. + +This filter expands or compresses each half-cycle of audio samples +(local set of samples all above or all below zero and between two nearest zero crossings) depending +on threshold value, so audio reaches target peak value under conditions controlled by below options. + +The filter accepts the following options: + +@table @option +@item peak, p +Set the expansion target peak value. This specifies the highest allowed absolute amplitude +level for the normalized audio input. Default value is 0.95. Allowed range is from 0.0 to 1.0. + +@item expansion, e +Set the maximum expansion factor. Allowed range is from 1.0 to 50.0. Default value is 2.0. +This option controls maximum local half-cycle of samples expansion. The maximum expansion +would be such that local peak value reaches target peak value but never to surpass it and that +ratio between new and previous peak value does not surpass this option value. + +@item compression, c +Set the maximum compression factor. Allowed range is from 1.0 to 50.0. Default value is 2.0. +This option controls maximum local half-cycle of samples compression. This option is used +only if @option{threshold} option is set to value greater than 0.0, then in such cases +when local peak is lower or same as value set by @option{threshold} all samples belonging to +that peak's half-cycle will be compressed by current compression factor. + +@item threshold, t +Set the threshold value. Default value is 0.0. Allowed range is from 0.0 to 1.0. +This option specifies which half-cycles of samples will be compressed and which will be expanded. +Any half-cycle samples with their local peak value below or same as this option value will be +compressed by current compression factor, otherwise, if greater than threshold value they will be +expanded with expansion factor so that it could reach peak target value but never surpass it. + +@item raise, r +Set the expansion raising amount per each half-cycle of samples. Default value is 0.001. +Allowed range is from 0.0 to 1.0. This controls how fast expansion factor is raised per +each new half-cycle until it reaches @option{expansion} value. +Setting this options too high may lead to distortions. + +@item fall, f +Set the compression raising amount per each half-cycle of samples. Default value is 0.001. +Allowed range is from 0.0 to 1.0. This controls how fast compression factor is raised per +each new half-cycle until it reaches @option{compression} value. + +@item channels, h +Specify which channels to filter, by default all available channels are filtered. + +@item invert, i +Enable inverted filtering, by default is disabled. This inverts interpretation of @option{threshold} +option. When enabled any half-cycle of samples with their local peak value below or same as +@option{threshold} option will be expanded otherwise it will be compressed. + +@item link, l +Link channels when calculating gain applied to each filtered channel sample, by default is disabled. +When disabled each filtered channel gain calculation is independent, otherwise when this option +is enabled the minimum of all possible gains for each filtered channel is used. +@end table + +@subsection Commands + +This filter supports the all above options as @ref{commands}. + @section stereotools This filter has some handy utilities to manage stereo signals, for converting |