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authorPavel Koshevoy <pkoshevoy@gmail.com>2012-06-17 12:35:57 +0200
committerStefano Sabatini <stefasab@gmail.com>2012-06-17 12:50:35 +0200
commita1aac8d004d1e3d415208fe0aea15b655826fb15 (patch)
tree7c380e32622f834e71604e7d8aa285871e68cbba /doc
parentbc4da77b081b9bf60310c292c2f90330c4ffa04b (diff)
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 <pavel@homestead.aragog.com> Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
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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.