From a1aac8d004d1e3d415208fe0aea15b655826fb15 Mon Sep 17 00:00:00 2001 From: Pavel Koshevoy Date: Sun, 17 Jun 2012 12:35:57 +0200 Subject: lavfi: add atempo filter Add atempo audio filter for adjusting audio tempo without affecting pitch. This filter implements WSOLA algorithm with fast cross correlation calculation in frequency domain. Signed-off-by: Pavel Koshevoy Signed-off-by: Stefano Sabatini --- doc/filters.texi | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'doc') diff --git a/doc/filters.texi b/doc/filters.texi index f2767cb974..a354e9703e 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -406,6 +406,24 @@ amovie=file.ogg [a] ; amovie=file.mp3 [b] ; [a2] [b2] amerge @end example +@section atempo + +Adjust audio tempo. + +The filter accepts exactly one parameter, the audio tempo. If not +specified then the filter will assume nominal 1.0 tempo. Tempo must +be in the [0.5, 2.0] range. + +For example, to slow down audio to 80% tempo: +@example +atempo=0.8 +@end example + +For example, to speed up audio to 125% tempo: +@example +atempo=1.25 +@end example + @section earwax Make audio easier to listen to on headphones. -- cgit v1.2.3