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author | Clément Bœsch <u@pkh.me> | 2015-08-10 22:03:11 +0300 |
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committer | Clément Bœsch <u@pkh.me> | 2015-09-06 16:28:21 +0300 |
commit | a388ca359d78c6fa00c75b326ada11048b1226ba (patch) | |
tree | f7f8db350504ad1bf74cf8f2d20611a4e800d9d8 /doc | |
parent | db18b3d6e6fa83eef862023d4c18bbe1113df075 (diff) |
avfilter/sine: support expression in the number of output samples
Diffstat (limited to 'doc')
-rw-r--r-- | doc/filters.texi | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/doc/filters.texi b/doc/filters.texi index d506d68a5e..7b9d665aea 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -2857,7 +2857,26 @@ Specify the sample rate, default is 44100. Specify the duration of the generated audio stream. @item samples_per_frame -Set the number of samples per output frame, default is 1024. +Set the number of samples per output frame. + +The expression can contain the following constants: + +@table @option +@item n +The (sequential) number of the output audio frame, starting from 0. + +@item pts +The PTS (Presentation TimeStamp) of the output audio frame, +expressed in @var{TB} units. + +@item t +The PTS of the output audio frame, expressed in seconds. + +@item TB +The timebase of the output audio frames. +@end table + +Default is @code{1024}. @end table @subsection Examples @@ -2878,6 +2897,12 @@ sine=f=220:b=4:d=5 sine=frequency=220:beep_factor=4:duration=5 @end example +@item +Generate a 1 kHz sine wave following @code{1602,1601,1602,1601,1602} NTSC +pattern: +@example +sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))' +@end example @end itemize @c man end AUDIO SOURCES |