[FFmpeg-user] Create an AAC stream matching the Core Media Audio packet format / priming etc?

Christian Ebert blacktrash at gmx.net
Fri May 26 14:53:44 EEST 2017

* Mark Burton on Wednesday, May 24, 2017 at 13:20:34 +0100
> On 23 May 2017, at 11:20, Christian Ebert <blacktrash at gmx.net> wrote:
>>> So I looked back at your above -af and realised that the 1024 should actually be 2112 which is Appleā€™s chosen fixed encoding delay.
>>> https://developer.apple.com/library/content/documentation/QuickTime/QTFF/QTFFAppenG/QTFFAppenG.html <https://developer.apple.com/library/content/documentation/QuickTime/QTFF/QTFFAppenG/QTFFAppenG.html>

Yes, the 'historical solution': implicit encoder delay:

>>> -filter:a aresample=async=1:first_pts=0,asetpts=PTS-STARTPTS+2112
>> Strange, probably all depends on the demuxing application.
> My take on it is that Quicktime will always assume 2112 padding, so I believe a .mov should be setup with this priming duration.

Yeah, filtering does not add an edit list (apparently the
'modern' solution):
and therefore QuickTime fails over to a hardcoded 'historical'
default. That explains it.

There are some options referring to edit lists, but I haven't
tried whether, nevermind how, they could be used for this

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