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tenoriocalc

Member

Registered: 2013-03-29

Posts: 8

Possible bug in ffmpeg-1:2.3 or libx265-1.2

Hi, all.

I used to record audio and video from a webcam with ffmpeg. My typical command line is:

/usr/bin/ffmpeg -y -f alsa -ac 1 -acodec pcm_s16le -vol 256 -ss 00:00:01.0 -i plughw:0,0 -f v4l2 -r 30 -s 640x480 -i /dev/video0 -t 63 -b:v 400000 /tmp/test.mpeg

Up to ffmpeg-1:2.2.1-1 and its dependence x265-0.9-1 everything was ok. But upgrading to ffmpeg-1:2.3-1/x265-1.2-1 produces .mpeg video files with inaudible audio. Encoding to a .mkv file works fine, but is too much cpu consuming for my proposes.

Recording audio and video separately to lately combine them also results in mute videos. I could not figure out whether to problem is caused by ffmpeg or libx265. Version 2.3.1 of ffmpeg did not solve the problem. By now I am using the downgraded packages. I would appreciate any better solution.

One curious fact about the issue: it occurs with kernels 3.14.x and 3.16.x, but with any subversion of kernel 3.15, the ffmpeg  command above freezes in a process impossible to kill.

Thanks.

Last edited by tenoriocalc (2014-08-17 21:03:36)

tenoriocalc

Member

Registered: 2013-03-29

Posts: 8

Re: Possible bug in ffmpeg-1:2.3 or libx265-1.2

I upgraded today to ffmpeg-1:2.3.3-1 and the issue partially improved. Now there is out of sync audio while playing videos in mplayer but none in vlc. Also videos appear like watching with fast forward.

Vlc outputs to terminal: "[0x7f1c74006f38] mpgatofixed32 audio converter error: libmad error: bad bitrate/mode combination".

Best regards.

Last edited by tenoriocalc (2014-08-19 02:01:21)

Barthalion

Forum Fellow

From: Poland

Registered: 2010-02-26

Posts: 111

Re: Possible bug in ffmpeg-1:2.3 or libx265-1.2

You should contact ffmpeg developers and try to debug the issue. In the meantime, it is safe to rebuild ffmpeg 2.2 against x265 available in our repositories and use it for a while – 2.2 and 2.3 are binary compatible.

DrZaius

Member

Registered: 2008-01-02

Posts: 193

Re: Possible bug in ffmpeg-1:2.3 or libx265-1.2

Please include the complete ffmpeg console output and any other information that is required to attempt to duplicate the issue.