[FFmpeg-devel] [DISCUSSION] Atrac3+ streams inside PSMF

[Maxim Polijakowski]

It looks like my previous email has been scrubbed. Therefore, I resubmit 
it in another thread. Sorry for that!

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Hello crews,
I would like to have a support for decoding/demuxing Atrac3+ streams 
from PSMF (Playstation movie format).
Although decoding/demuxing of video streams currently does currently 
work, audio streams stay still unaccesible. I'm ready to undertake this 
task but I need a liitle bit help (see below).
PSMF BACKGROUND:
PSMF container can be seen as an extension of MPEG-TS, see here: 
http://wiki.multimedia.cx/index.php?title=PSMF 
<https://3c.gmx.net/mail/client/dereferrer?redirectUrl=http%3A%2F%2Fwiki.multimedia.cx%2Findex.php%3Ftitle%3DPSMF>
In the current FFMpeg, PSMF will be (mis)-identified as MPEG-TS stream. 
Atrac Audio is carried out in PRIVATE_STREAM_1 packets. Their format is 
proprietary but rather simple to understand.
Atrac3+ audio streams are delivered inside of packets of the same size, 
usually 2048 bytes. They usually contain several audio frames. Frames 
can be splitted across two packets and need to be stitched together in 
the demuxer.
Now my questions:
1) what's the proper code to be extended? I attached a very draft patch 
that extends the MPEG demuxer. Is it the right place or should I look 
for any other?
2) how to deal with multiply frames in a packet? Could you point me to a 
working example?
3) audio frames can be splitted into two parts and sent with two 
different packets in the case audio frame size is not an integral of 
2048 bytes. It means the demuxer should save the first part in a 
temporary location, wait for the 2nd part and then concatenate these two 
parts together. Is there any API or working examples doing that I could 
look into?
I did never implemented a demuxer of such a complexity so I would 
greatly appreciate any help.
Thank you in advance!
Best regards
Maxim
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