[Matroska-devel] Request for information to improve the interaction between Windows VC1, H.264 decoders and Haali Media Splitters

Harsha Kikkeri (CODECS & DSP) harshk at microsoft.com
Tue Dec 30 20:50:18 CET 2008

Hi Matroska Developers,

I work in the codecs team of Microsoft, which is responsible for VC1/H264/MPEG2 inbox decoders.
According to the change list, you made certain changes for working around the limitations of the VC1 decoder.

1) Fixed handling of VC-1 with changing sequence headers in PS and TS containers
2) Fixed VC-1 aspect ratio detection
3) Added a workaround to make MS VC-1 DMO decoder accept formats with included aspect ratio information

We have already fixed 1) for Windows 7 where the VC1 decoder can now handle dynamic format changes.

We would like to fix 2) and 3) as well. Looking at our code, we do handle aspect ratio when the media type is VideoInfoHeader2 (VIH2).

Could you tell us more about the problem that you faced? It would be great if you could share the media files which exhibited the problems with an older version of Haali media splitter without the fixes.

Also, the splitter is not inserting start codes for 'AVC1' format, could you add an additional output media type 'H264' so that inbox decoder can play such content?

When splitter is connected using 'H264' media type it should
1.       Send SPS and PPS NALUs as part of compressed bitstream data, and
2.       Insert start codes and send AVC bitstream as explained in Byte Stream Format section of Annex B of ISO/IEC 14496-10.

This posting is provided "AS IS" with no warranties, and confers no rights.

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