[FFmpeg-trac] #4158(undetermined:reopened): Audio Stream loss after codec change

FFmpeg trac at avcodec.org
Thu May 12 20:37:18 CEST 2016

#4158: Audio Stream loss after codec change
             Reporter:  jimbob       |                    Owner:
                 Type:  defect       |                   Status:  reopened
             Priority:  normal       |                Component:
              Version:  git-master   |  undetermined
             Keywords:               |               Resolution:
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
Changes (by jimbob):

 * status:  closed => reopened
 * resolution:  needs_more_info =>



 I checked bug reports for this bug but was unable to correct it (except
 reported for an older version): See #3553, and
 https://ffmpeg.org/pipermail/ffmpeg-user/2013-May/015184.html. I don't
 suspect these issues are related.

 I have two sample videos now. Only 5 minutes each. I just happened to get
 lucky and noticed it shortly after restarting the stream. Thankfully I
 have multiple copies of this problem, it seems to affect both video output
 as well as video 'input'. Time of occurrence is roughly between 3 minutes
 to the end of the video. Skipping it in VLC has no effect on the fact that
 audio is not present; nor is it restored.

 Version: FFMPEG 2.8-static and FFMPEG 2.4.2

 Original parameters:
 /home/user/ffmpeg_run/ffmpeg -i
 "udp://" -vf yadif -map 0 -c:a copy
 -vcodec libx264 -b:v 5000k -bufsize 12000k -g 60 -preset superfast -tune
 zerolatency -f "mpegts udp://"

 /home/user/ffmpeg_run/ffmpeg -i
 "udp://" -y -f mpegts WGN-input.raw

 /home/user/ffmpeg_run/ffmpeg -i
 "udp://" -y -f mpegts WGN-output.raw

 We receive the stream from an authorized satellite receiver via unicast,
 it hits a multicast server; this then broadcasts the output which is
 received by these transcoding servers. We are confident that this issue is
 not a problem with the multicast server because we can tune into the
 stream without any problem after the audio has been "muted" after it
 passes the ffmpeg processes. This issue has been omnipresent since version
 2.4 and earlier.

 Please feel free to pass input.raw and output.raw through the latest
 ffmpeg build to see if it corrects the problem: I have a feeling that it

 I have uploaded WGN-PUT.txt to your file server, as well as the input and
 output files respectively. The only real output to the screen is the
 message in WGN-PUT.txt.

Ticket URL: <https://trac.ffmpeg.org/ticket/4158#comment:4>
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