[M4IF Technotes] Reference software Error Resilient

[Kris Huber]

Hello Yoong-Choon,
Yes, I think what you say is true of the reference software not handling
bitstreams with errors.  Many parts of error resilience you are free to do
as you wish, as there are various ways of doing it.  I'm sure there are
technical papers and likely companies and consultants that can help figure
out how to do that, or to do it outright.  At some point during the
standardization process I think there were experiments to prove that the
error-resilient syntax elements provided were sufficient to implement
effective error resilience (or something sufficient to achieve consensus on
the technical merit of the syntax), but the reference software does not
necessarily include non-normative features.  A conformant a decoder is free
to crash in the case of a bitstream error, just as the reference software
does, or it may do something very simple like produce black VOPs until the
next video sequence comes along.  What the conformant decoder (of profiles
including the error-resilience tools) must do is to properly decode the
error-resilient syntax when there are no bitstream errors.  This ensures
that encoders can safely use the error-resilient syntax in the broadcast
situation, for example, instead of having to transmit a version for the
reliable channels and another version for the error-prone channels.  Such an
approach has the potential to be more bandwidth-efficient overall (the
dual-channel approach is still possible using MPEG video, of course).  For
decoders operating at the end of an error-prone link, what is done with the
syntax elements designed to enable error-resilience becomes more important.
But what is appropriate is an implementation decision that depends upon how
much computation and memory is available at the decoder, not to mention the
error characteristics of the particular channel and the encoder's usage of
the syntax.  The market is left to sort out and ultimately decide among the
numerous possibilities for the error-resient decoder functionality.
Regards,
Kris
-----Original Message-----
From: Chang Yoong Choon [mailto:cychoon   hotmail.com]
Sent: Thursday, December 20, 2023 6:25 PM
To: technotes   lists.m4if.org
Subject: [M4IF Technotes] Reference software Error Resilient
Dear All:
I am using Microsoft ISO MPEG-4 reference software. Whenever I try to decode
MPEG-4 bitstream with errors, the decoder will crash or stop decoding.
According to ISO MPEG-4 reference software manual, the current decoder
supports error resilient bitstream but does not have error recovery, error
detection, error concealment functions. In other words, whenever the decoder
encounter bitstream error during decoding process, it will stop decoding.
Where can I find MPEG-4 decoder that support error resilient and have error
detection, error detection, error recovery, error concealment functions?
How can I modify the Microsoft MPEG-4 refernece software so that it can
decode bitstream with errors? Which file in the source code should I modify?
Does MoMuSys MPEG-4 reference software decoder support error resilient
functions? Can the decoder decode MPEG-4 bitstream with errors?
Many thanks for your help.
regards
Yoong-Choon Chang
  _____  
Get your FREE download of MSN Explorer at http://explorer.msn.com
<http://go.msn.com/bql/hmtag_etl_EN.asp> .
_______________________________________________ Technotes mailing list
Technotes   lists.m4if.org http://lists.m4if.org/mailman/listinfo/technotes
-------------- next part --------------
An HTML attachment was scrubbed...
URL: /pipermail/mp4-tech/attachments/20011221/95e84c7b/attachment.html