[FFmpeg-cvslog] avfilter/af_volume: fix precision=fixed and volume=0 case

[Gilles Chanteperdrix]

ffmpeg | branch: master | Gilles Chanteperdrix <gilles.chanteperdrix at xenomai.org> | Sat Feb 28 23:15:39 2015 +0100| [dcf19008a67f35ae817a7af65ce2625a82acb641] | committer: Michael Niedermayer

avfilter/af_volume: fix precision=fixed and volume=0 case

When precision is fixed and volume is 0, filter_frame does not
perform any operation on the output buffer. This works if the
output buffer has been allocated and zeroed with ff_get_audio_buffer
but not if the input buffer is used as output buffer.

Fix this by not using the input buffer as output buffer if
precision is fixed and volume is 0.

Signed-off-by: Gilles Chanteperdrix <gilles.chanteperdrix at xenomai.org>
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=dcf19008a67f35ae817a7af65ce2625a82acb641
---

 libavfilter/af_volume.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavfilter/af_volume.c b/libavfilter/af_volume.c
index 4809ae7..8d49c65 100644
--- a/libavfilter/af_volume.c
+++ b/libavfilter/af_volume.c
@@ -402,7 +402,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
     }
 
     /* do volume scaling in-place if input buffer is writable */
-    if (av_frame_is_writable(buf)) {
+    if (av_frame_is_writable(buf)
+            && (vol->precision != PRECISION_FIXED || vol->volume_i > 0)) {
         out_buf = buf;
     } else {
         out_buf = ff_get_audio_buffer(inlink, nb_samples);