[Ffmpeg-devel] Re: [PATCH] non conformance to 3GP format (3GP TS 26.244 v 6.5.0 2006/06) 2nd try
Sun Aug 6 22:38:57 CEST 2006
On Sun, Aug 06, 2006 at 10:13:09PM +0200, Baptiste Coudurier wrote:
> Michael Niedermayer wrote:
> >> [...]
> >> Michael, do you think we should keep using AVI fourcc ? The more I read
> >> specs and the more I feel we should not do that and strictly mux
> >> according to specs.
> > hmm, where do we use avi fourcc in mov/mp4 except if theres no mov fourcc
> > maybe?
> Yes when there is no mov fourcc. Personnaly I would prevent using them
> except manually when they use vtag.
what about requireing -strict -1 ?
> >> [...]
> >> - }
> >> + /* FIXME not sure, ISO 14496-12 specifies either 1 or 2, no samples found where channels > 2 */
> >> + if (track->mode == MODE_MOV || (track->mode == MODE_MP4 && track->enc->channels < 2))
> >> + put_be16(pb, track->enc->channels);
> >> + else
> >> + put_be16(pb, 2); /* Reserved */
> > does the spec just not specify how to store streams with more then 2 channels
> > or does it explicitly say that >2 channels audio should have 2 in the channels
> > field?
> Quoting ISO 14496-12:
> "template unsigned int(16) channelcount = 2;"
> "ChannelCount is either 1 (mono) or 2 (stereo)"
> Would mean 2 is default value.
> Like I said I'm not sure. Im looking for ISO 14496-3 AMD 3 which
> specifies mp3on4, mp3 5:1. Maybe they override specs for mp4, maybe not.
> All mp3on4 5:1, vorbis 5:1, aac 5:1 samples I could find have 2 for
> channelcount, while mov with 5:1 from apple have 6 as channelcount.
hmm, hmmmmmm :(
i still think channel count is the count of channels and not 2 ...
so unless this breaks something my vote would be to store the correct
number of channels, after all the specs you quote dont say store 2 if
there are more then 2 channels they just dont say anything about more
then 2 ...
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is
More information about the ffmpeg-devel