[Mp4-tech] Microsoft MPEG-4 Reference Decoder with packet loss

[Stefan A. Goor]

Hey All,
Hopefully someone can help me with this.
I have used the MPEG4IP tools to create hinted mp4 files that contain mpeg4
bitstreams created with the MS Encoder Reference Software and I have placed
these files on the Darwin Streaming Server to allow RTSP access.
When I write the payload of the packets received by the RTSP client to a
file, I can decode it with the MS Reference Decoder.  However if I drop any
packet, the decoder stops with a dialog box on the screen that says "Debug
Error!... ...abnormal program termination..." and the decoder prints the
following message in the dos window:
	Assertion failed: iMbType >= 0 && iMbType <= 3, file
d:\ms_om\sys\decoder\mbheaddec.cpp, line 476
>From what I understand, the MPEG-4 decoder should be able to handle losses
and corruption (isn't one of the main goals of MPEG-4 to be highly error
resiliant?).
Could anyone explain what the problem may be and how I may get around it?
I would like to be able to decode content has been sent over a network and
that may have approximately 0.5% packet loss.
Also, I assume that each packet or at least an integer number of packets
corresponds to a single frame, is this true?
>From RFC 1889 for RTP, I see that there is a marker bit that generally
indicates frame boundaries.  In MPEG-1 and 2 there was a specific code that
determined the start of a frame, is there something similar for mpeg4 video
stream?
Any help with these problems and questions would be greatly apreciated,
Many thanks,
Stefan