[Mp4-tech] Anybody Knows Microsoft MPEG-4 Codec V2 ('mp42')Features ?

[Gary Sullivan]

Philip et al,
There have been several generations of Microsoft product implementations of MPEG-4 Visual.
The encoder called "mp4s", also known as "ISO MPEG4 v1.0", should be a fully conforming encoder.
The decoder called "m4s2", also known as "ISO MPEG4 v1.1", should be a fully conforming decoder.
(There was apparently no "v1.1" necessary for the encoder.)
I think those are the preferred versions for compatibility purposes.
The "mp42" codec is probably not really the right thing to be using.
Regarding your search for start codes -- I think mp42 was used in a specialized systems/file environment where start codes may not have been needed.  In such uses it is possible to avoid the overhead associated with start codes (see for example, RFC 2429 where I believe start code overhead was also minimized for a similar purpose).
Best Regards,
Gary Sullivan
________________________________
From: mp4-tech-bounces lists.mpegif.org on behalf of Philip Hong
Sent: Fri 8/20/2004 12:23 AM
To: mp4-tech lists.mpegif.org
Subject: [Mp4-tech] Anybody Knows Microsoft MPEG-4 Codec V2 ('mp42')Features ?
I tried to find what compression features are provided by Microsoft
MPEG-4 Codec V2, however I found that the compressed data do not contain
any valid ISO 14496-2 encoded data pattern, e.g. frame start code - "00
00 01 B6".
Can anybody tells me what kind of data format Microsoft is using ?
Thanks in advance.
-- Philip
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