[FFmpeg-devel] [RFC] Private streams in MPEG PS

Jai Menon jmenon86
Wed May 27 20:00:39 CEST 2009


I'm becoming increasingly suspicious of this check in lavf/mpeg.c:370 -

  4093        mru     if (startcode == PRIVATE_STREAM_1 &&
!m->psm_es_type[startcode & 0xff]) {


Looking at issue 1122 and 725 on roundup,  I'm inclined to believe
that a lot of files out there don't have a program stream map (which I
didn't back when issue 725 was reported). Removing this check actually
would solve both 1122 and 725 without the need for the fix commited in

A related question is how we would handle two streams with the same
startcode, one of which is a private substream, because the lavf
stream id is set to the startcode value and is expected to be unique.
Is such a situation impossible? If it isn't should the startcode for
the private substream be conactenated with 0x1bd to produce a unique

Thoughts, comments?

Please point out any mistakes/alternate fixes, I don't have a copy of
the mpeg systems spec and my understanding is limited by the samples I



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