Hi people !

I know that Microsoft is a core member of the MPEG video group and that MS video codecs are based upon MPEG technology.

But what about MS Audio codecs. Due to proprietary issues you just can't get any technical ressources about it. It's the same deal about Real Audio whereas both are leaders when it comes about streaming multimedia content over the Internet.

Does anyone know what WMA and Real Audio are all about ? Did they develop totally independent algortihms ?

Thank you all.

Now with WM9 the codecs are not based on MPEG. Not the video, OR the audio. Microsoft no longer uses MPEG-4.
Yes, they did develop independent algorithms.

You have any references to that?

I read it at the Doom9.net forum, can't remember where exactly though. In the XviD forum i believe. Someone asked if maybe XviD people can learn something from microsoft's new format and an XviD developer said that not because microsoft no longer has anything to do with MPEG, and of course because their closed formats.

Microsoft used to work with MPEG-4 *video* group.
check this url : http://www.avsforum.com/avs-vb/showthread....threadid=167956

At the bottom of the page some guy from Microsoft relpies a topic and talks about it. Anyway i always heard Microsoft holds patents in MPEG-4 VIDEO technology. But i don't know anything about WMA. I guess u're right, that must be totally independent....

Yep Microsoft holds patents which are included in the MPEG-LA licensing pool for MPEG-4 video. One of the ISO reference MPEG-4 source code distributions was written completely by Microsoft employees, but frankly the code is a mess and is only really useful to us as an error-checking platform.

I'm not sure what their new codec is derived from - the old MSMPEG4vX codecs were just MPEG-4 simple profile with some more VLC tables and different motion vector behaviour, but WMV8 and 9 have gotten much much slower. That means (I hope) more functionality.

My guess is that there are some new features similar to H.26L - post-processing included in the encoder loop, multiple-reference P-frames, maybe even wavelets for intra blocks/frames. Of course there's no way to know, as there's no spec we have access to

-h

I'd be happy if MS would disclose details about their WMV9 codec. And the specs of a WM9 DVD/VideoCD layout too.