[FFmpeg-devel] Collection of patches

Thorsten Jordan tjordan
Wed Apr 23 15:58:22 CEST 2008

Michael Niedermayer schrieb:
> On Wed, Apr 23, 2008 at 09:15:40AM +0200, Thorsten Jordan wrote:
> [...]

>> work. Maybe it has been fixed differently meanwhile, but i can't
>> imaginge how.
> Your patch generates invalid/broken h264. The current code generates broken
> ones too but they dont work which prevents them from spreading. Thus your
> patch clearly makes it worse, the issue is not fixed it just appears that it
> is. The spliting API in ffmpeg has to be changed to allow spliting random
> subsets of the headers out. Please see the mailing list where i described
> this more precissely IIRC.
ah now i see your point. The splitter should thus extract the SPS and
PPS only and put it in extradata, and leave the rest of the stream as it
is (including the SEI NALs). If there are NALs other than SPS/PPS
inside, it would be incompatible to MP4 extradata format, as it expects
only SPS and PPS units.
So if there is "SPS - SEI - PPS - other/rest..." in the stream, extract
"SPS - PPS" to extra data, and keep "SEI - other/rest..." in the stream

In the discussion about that problem on this list, you said that the two
SEI NALs in my example shouldnt be part of global headers. I checked the
h264 spec and there are 22 types of SEIs. None of them sound like they
are SPS/PPS related.

Which brings up the question if there should be never SEI units in
global headers. I found nothing near the SPS/PPS description that
mentions SEI, so they are not used as header extension?

Regards, Thorsten

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