[FFmpeg-trac] #6343(undetermined:new): Encoding MP4/AAC audio from pcm: issues with packets, duration, and pts/dts (especially when using -movflags empty_moov)

FFmpeg trac at avcodec.org
Sun Apr 23 00:33:13 EEST 2017


#6343: Encoding MP4/AAC audio from pcm: issues with packets, duration, and pts/dts
(especially when using -movflags empty_moov)
-------------------------------------+-------------------------------------
             Reporter:  ea167        |                    Owner:
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
              Version:  git-master   |  undetermined
             Keywords:  mp4 aac pcm  |               Resolution:
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
-------------------------------------+-------------------------------------

Comment (by heleppkes):

 AAC uses a concept of decoder priming, ie. before the actual data can be
 decoded properly, it decodes a bit of nothingness to "start" the decoder.
 This data is typically 1024 samples long, and thats where you get your
 extra frame from.

 This extra frame is generally properly marked as such and the delay set
 appropriately, so after decoding you should once again have the same
 amount of samples as you put in.

 PS:
 As a general rule, its greatly advised to report one particular issue in
 one ticket, and not bunch all your collected issues into one.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/6343#comment:1>
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