[FFmpeg-devel] [DISCUSSION] Atrac3+ streams inside PSMF
Carl Eugen Hoyos
cehoyos at ag.or.at
Tue Nov 25 17:56:36 CET 2014
Maxim Polijakowski <max_pole <at> gmx.de> writes:
> In the current FFMpeg, PSMF will be
> (mis)-identified as MPEG-TS stream.
I thought it is correctly identified as mpeg-ps.
> 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.
That means you have to implement an atrac3p parser,
see many examples in the libavcodec directory.
> 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?
If the files can be identified as pmf, please add
a new field similar to the existing imkh_cctv and
sofdec fields and use that new field to decide that
PRIVATE_STREAM_1 packets are atrac3p.
(Additionally, allow users to force atrac3p for
cut streams with ffmpeg -acodec atrac3p -i input.)
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