[Mp4-tech] Re: [MPEG4][Audio] Handling erroneous aac streams

[Ralph Sperschneider]

S. R. Quackenbush wrote:
> Dear Brata,
> 
> If you are reading the AAC stream from an MPEG-4 file then you know the
> AccessUnit framing and one AccessUnit is typically one AAC raw data block.
> Since each AAC raw data block is decodable by itself (subject to boundary
> overlap-add errors), you can skip forward and backward as you wish.
> 
> If you really have an MPEG-2 AAC bitstream, which is a sequence of AAC raw
> data blocks, you have to parse every block to know when the next starts.
> Sorry!

Unless ADTS is used, which comes with its own sync and framing.
But since we (according to the subject) most likely talk about MPEG-4, why not 
mention LOAS/LATM, which is the (more flexible) MPEG-4 Audio transport and 
multiplex scheme?
BTW: It would very much help if questioners would clearly state what they have 
and what they want (MPEG-2 AAC (which profile?) or MPEG-4 AAC (which AOT?), kind 
of transport (ADTS, LATM) or file format (ADIF, MP4FF)).
Ralph
-- 
Dipl.-Ing. Ralph Sperschneider  | Phone: +49 9131 776 344
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