[FFmpeg-trac] #9433(undetermined:open): FFmpeg fails to decode AAC with embedded tags

FFmpeg trac at avcodec.org
Tue Sep 28 01:35:31 EEST 2021


#9433: FFmpeg fails to decode AAC with embedded tags
-------------------------------------+-------------------------------------
             Reporter:  shirt        |                    Owner:  (none)
                 Type:  defect       |                   Status:  open
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  git-master   |               Resolution:
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Comment (by jeeb):

 This seems to be a concatenated stream from a set of HLS segments.

 A patch:
 https://patchwork.ffmpeg.org/project/ffmpeg/patch/20210927213133.28258-1-jeebjp@gmail.com/
 .

 It would be very lovely if someone could figure out what those occasional
 padding bytes are and if they should even exist when such a raw ADTS
 stream is concatenated during ripping/dumping. As currently enabling
 resync to work just means that:

 1. The ADTS reader is able to proceed (in other words, parsing of the
 audio bits of the ADTS stream should work).
 2. You are most likely losing all of the following ID3 metadata as the
 resync will skip until the next valid ADTS start code.

 So if the padding is not supposed to be there when the stream is ripped
 and concatenated, then the ripping application should be fixed to not have
 this stuff. Otherwise if there is a specification for this stuff, that
 should be noted so that proper improvements can be made if necessary.

 In this sample it looks like this:


 {{{
 [ADTS packet]
 [0x0b .... or so padding]
 [ID3 magic]
 }}}

 Previously it would fail at the second set of 0x0bs, at offset 5053141 as
 that is more than the default probesize of 5000000.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9433#comment:3>
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