[Ffmpeg-devel] Re: [PATCH] non conformance to 3GP format (3GP TS 26.244 v 6.5.0 2006/06) 2nd try

Baptiste Coudurier baptiste.coudurier
Mon Aug 7 11:56:22 CEST 2006


Michael Niedermayer wrote:
> [...]
> what about requireing -strict -1 ?

Ah, does AVFormatContext support strict ?


> 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 ...

Ok I think I found the truth:

Quoting ISO 14496-1 AMD 6 4. Composition:
"In MPEG-4 both visual and aural composition are done using the BIFS
system.  Therefore structures marked as "template" in the ISO Base Media
Format which pertain to composition, including fields such as matrices,
layers, graphics modes (and their opcolors), volumes, and balance
values, from the MovieHeaderBox and TrackHeaderBox, are all set to their
default values in the file format.  These fields do not define visual or
audio composition in MPEG-4; in MPEG-4, the BIFS system defines the

Since channelcount is mentioned as template it must be left as 2.

PS: sorry gmane fucked up and I lost one mail. I hope I did not break
the thread. I now quit using gmane.

Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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