[Ffmpeg-devel] wmv3 complex profile and vc1 frame error sample

[Kostya]

On Fri, Mar 16, 2007 at 08:47:51PM +0100, matthieu castet wrote:
> Kostya wrote:
> >On Fri, Mar 16, 2007 at 12:13:20PM -0500, Compn wrote:
> >>first is a wmv3 complex profile sample
> >>mms://vipmms.canalplus.fr/canalplus/zapping_`date --date "1 days ago"
> >>+'%y%m%d'`_a.wmv
> >>
> >>mms://vipmms.canalplus.fr/canalplus/zapping_070315_a.wmv
> >>
> >>[wmv3 @ 00B26C34]WMV3 Complex Profile is not fully supported
> >>[wmv3 @ 00B26C34]1 for reserved RES_X8 is forbidden
> >>[wmv3 @ 00B26C34]0 for reserved RES_FASTTX is forbidden
> >>
> >>the stream starts with some picture errors, and some errors
> >>occur during scene change. is it useful to you ?
> >
> >That's because of X8 frames. They are used as keyframes and use alternate
> >encoding scheme. They are the same (except frame header) to WMV2 J-frames.
> >If only Michael provided some info on their structure... :(
> 
> So you mean there no description of them in VC-1 reference 
> implementation or Specs.

Right, the only mention was as reserved flags in sequence header for simple
and main profile in VC9 (yes, 9 then) draft. SMPTE 421m missed even this.
 
> This is a wmv3 only featue ?

Yes, and there are some more features like this. For example, old WMV3
coded P-frames can not be decoded with reference decoder too.

> 
> Matthieu
>