lavfi: add asetnsamples audio filter

This filter changes the number of samples on single output operation.

Based on a patch by Andrey Utkin <andrey.krieger.utkin@gmail.com>.

1 files changed, 30 insertions, 0 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 67242af136..f2767cb974 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -273,6 +273,36 @@ For example, to resample the input audio to 44100Hz:
 aresample=44100
 @end example
 
+@section asetnsamples
+
+Set the number of samples per each output audio frame.
+
+The last output packet may contain a different number of samples, as
+the filter will flush all the remaining samples when the input audio
+signal its end.
+
+The filter accepts parameters as a list of @var{key}=@var{value} pairs,
+separated by ":".
+
+@table @option
+
+@item nb_out_samples, n
+Set the number of frames per each output audio frame. The number is
+intended as the number of samples @emph{per each channel}.
+Default value is 1024.
+
+@item pad, p
+If set to 1, the filter will pad the last audio frame with zeroes, so
+that the last frame will contain the same number of samples as the
+previous ones. Default value is 1.
+@end table
+
+For example, to set the number of per-frame samples to 1234 and
+disable padding for the last frame, use:
+@example
+asetnsamples=n=1234:p=0
+@end example
+
 @section ashowinfo
 
 Show a line containing various information for each input audio frame.