[FFmpeg-trac] #3231(documentation:new): Muxing libvorbis audio fails; no sound in the output file

FFmpeg trac at avcodec.org
Thu Dec 19 22:58:36 CET 2013

#3231: Muxing libvorbis audio fails; no sound in the output file
             Reporter:  gyunaev      |                    Owner:
                 Type:  defect       |                   Status:  new
             Priority:  minor        |                Component:
              Version:  git-master   |  documentation
             Keywords:               |               Resolution:
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0

Comment (by gyunaev):

 As far as I know, {{{ FFmpeg  }}} cannot generate video/audio as muxing.c
 does. It works with the external input audio and video streams, and in
 converting those it uses the DTS/PTS information from those streams.

 muxing.c however does not use any external streams, and generates the
 video and audio streams internally. Thus it cannot rely on provided
 PTS/DTS and has to supply it. muxing.c does it for video, but not for
 audio. This works fine with the majority of formats, but it does not work
 with WEBM or theora/vorbis.

 This could mean that FFmpeg coders are ok and muxing.c needs fixing
 (because changing in as above fixes the output for theora/vorbis, although
 not for WebM). This could also mean there's a bug in  relevant
 codec/format parser in FFmpeg, and the change above just avoids this bug
 in some way. This theory could be further supported by the fact that any
 other format except Vorbis audio muxes fine with the unmodified example,
 while any format containing Vorbis audio fail to mux properly.

 This is important issue because the muxing example is the only one which
 is relevant for applications such as my
 [http://sourceforge.net/projects/karlyriceditor Karaoke Lyrics Editor]
 (which is a free GPL app) which generates an AV interleaved file based on
 the user entered data.

Ticket URL: <https://trac.ffmpeg.org/ticket/3231#comment:9>
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