[FFmpeg-devel] [PATCH/RFC] H.264 FMO+ASO decoding

Reimar Döffinger Reimar.Doeffinger
Thu Jul 22 19:19:52 CEST 2010

On Thu, Jul 22, 2010 at 12:50:22AM +0200, Stefan Gehrer wrote:
> On 07/22/2010 12:32 AM, Reimar D?ffinger wrote:
> >On Wed, Jul 21, 2010 at 10:20:36PM +0200, Stefan Gehrer wrote:
> >>Unfortunately, the real challenge starts here.
> >
> >I suspect it starts earlier. Have you checked the parser?
> >Because I think it won't be able to properly split things into
> >access units if FMO is used.
> I can't see a problem there. IMHO the criteria of when a new
> access unit starts does not change with FMO or ASO and the parser
> correctly ignores the first_mb_in_slice value.

There is this in the H.264 parser:
            if(buf[i] & 0x80)
                goto found;
which IIRC is basically "if (first_mb_in_slice == 0)"...
So it will split on whichever slice starts with MB 0.

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