[Matroska-devel] MVC codec in Matroska container

Mike Chen mike at makemkv.com
Fri Dec 14 11:27:27 CET 2012

Hash: SHA1

On 12/14/2012 10:02 AM, Moritz Bunkus wrote:
> Meaning... the only difference to the previous proposal would be
> the 'CPex' identifier. The advantage is that no guesswork is
> required. A parser looking for the extensions could simply look for
> this string at the end of the avcC.
> The other way is also safe: a parser not expecting the 'CPex' 
> extension but the chromaInf would see three bytes 0x43 50 65, in 
> binary: 01000011 01010000 01100101. Those do not match the
> reserved '1' bites from the chromaInf field at all, meaning the
> parser would have to consider them invalid.

I thought about this as well but came to opinion that this is not
necessary as the length is bound to be below 64K so the first two
bytes of the extension are always two zeros and they are bound to be
different from any avcC extension.

I'm neutral on this issue - either way works for me as long as
majority agrees.

But if we go this way we might wrap all data after avcC in the full
mp4 box as well, by adding length of entire CPex structure before
CPex. This would remove any ambiguity and make parsing of atom list
somewhat easier as length will be double-confirmed.

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