[FFmpeg-trac] #2325(undetermined:open): MP4 AAC Audio is delayed by 2ms when converted to PCM

[FFmpeg]

#2325: MP4 AAC Audio is delayed by 2ms when converted to PCM
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             Reporter:  BChap        |                    Owner:  (none)
                 Type:  defect       |                   Status:  open
             Priority:  important    |                Component:
                                     |  undetermined
              Version:  git-master   |               Resolution:
             Keywords:  aac mov      |               Blocked By:
  regression                         |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Comment (by Bartek Zdanowski):

 I've run at this problem a few days ago.

 From my perspective it's a problem with aac at FFmpeg's side. Not from the
 side of the codec.

 I generate 1 frame (1024) of silence or sinus samples but ffmpeg adds
 about two frames o silence before my frame.
 Same happens when I push packets of existing audio from some source.
 FFmpeg adds two frames of silence in the beginning.

 No such thing happens for other codecs. Checked with ac3 and eac3. Audio
 starts correctly from first sample. No silence added in the beginning.

 I'm absolutely sure about my data I feed into ffmpeg so please don't
 argue.

  There's some kind of problem with ffmpeg-aac code. I've tested is with
 * aac builtin
 * libfdk-aac

 BOTH have a problem with adding about two frames of silence in front of
 passed audio.
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Ticket URL: <https://trac.ffmpeg.org/ticket/2325#comment:21>
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