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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/filters.texi | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/doc/filters.texi b/doc/filters.texi index 477f833449..73537c524f 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -926,6 +926,7 @@ afftfilt="1-clip((b/nb)*b,0,1)" @end example @end itemize +@anchor{afir} @section afir Apply an arbitrary Frequency Impulse Response filter. @@ -4873,6 +4874,33 @@ anoisesrc=d=60:c=pink:r=44100:a=0.5 @end example @end itemize +@section hilbert + +Generate odd-tap Hilbert transform FIR coefficients. + +The resulting stream can be used with @ref{afir} filter for phase-shifting +the signal by 90 degrees. + +This is used in many matrix coding schemes and for analytic signal generation. +The process is often written as a multiplication by i (or j), the imaginary unit. + +The filter accepts the following options: + +@table @option + +@item sample_rate, s +Set sample rate, default is 44100. + +@item taps, t +Set length of FIR filter, default is 22051. + +@item nb_samples, n +Set number of samples per each frame. + +@item win_func, w +Set window function to be used when generating FIR coefficients. +@end table + @section sine Generate an audio signal made of a sine wave with amplitude 1/8. |