[FFmpeg-trac] #1638(avformat:open): SWF demuxer cannot correctly identify MP3 stream

FFmpeg trac at avcodec.org
Sat Sep 29 17:25:42 CEST 2012

#1638: SWF demuxer cannot correctly identify MP3 stream
             Reporter:  mbradshaw   |                    Owner:
                 Type:  defect      |                   Status:  open
             Priority:  normal      |                Component:  avformat
              Version:  git-master  |               Resolution:
             Keywords:  swf         |               Blocked By:
             Blocking:              |  Reproduced by developer:  1
Analyzed by developer:  0           |

Comment (by michael):

 Replying to [comment:2 mbradshaw]:

 > Anyway, the audio is not streamed in the frames. Instead, in this file,
 it is found in a DefineSound tag (tag code = 14), and the entire MP3 file
 is stored as part of this tag. FFmpeg does not look for any DefineSound
 tags. I could easily add the necessary code to find and parse a
 DefineSound tag, but I'm unsure of how to properly demux this sound
 because it's not broken up into frames (like audio (TAG_STREAMHEAD(2)) or
 video (TAG_VIDEOSTREAM) streams are). Audio in DefineSound tags come in
 one solid chunk.

 You can return randomly (or fixed) sized chunks from the mp3 and set
 AVStream->need_parsing appropriately then libavformat will break things
 into chunks for you

Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1638#comment:3>
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