[M4IF Technotes] question on error resilience for simple prof ile

[Shanableh Tamer-BTS027]

Ken,
The three resilience modes you are referring to i.e. Video Packet structure, Data partitioning and reversible VLCs are arranged in a rather hieratical manner. That is Data partitioning is employed within Video Packets and RVLCs are employed with data partitioning. Therefore some modes cannot be enabled on there own.
For mobile use, the least that the encoder is recommended to enable is the Video Packet structure and the optional Header Extension (HE). Mind you that HE does not have to be enabled for all the Video Packets rather, the first and/or the second packets only. As such the decoder should be able to localise errors and resync its decoding process. More importantly, if the VOP header is corrupted then it can be rectified by the replicated information decoded from the HE.
If more protection is needed or in other words if a better concealment quality is sought then the encoder might want to enable Data partitioning. Likewise sparsely populated RVLCs makes it easier for decoders to detect invalid VLC codes.
Furthermore, conformant Simple Profile decoders have to recognise and decode the three resilience modes. Mind you that this should be quite simple and straightforward. The decoder has to understand the syntax of resync markers and reset its predictors once a Video Packet is encountered and so forth. As for RVLC it is a matter of using a different set of VLC tables. This is what is required for the decoder to be compliant, therefore to my understanding such an implementation is not at all onerous. On the other hand, error detection and concealment benefit from proprietary techniques and algorithms that can be added to the decoder.
Tamer Shanableh
Motorola
-----Original Message-----
From: Chen, Kenny [mailto:kenny.chen   intel.com]
Sent: Monday, June 10, 2023 19:28
To: Rob Koenen; M4IF FORUM
Subject: RE: [M4IF Technotes] question on error resilience for simple prof ile
Rob,
Thanks for your support!
Say, we want to use the error resilience for wireless channel.  There are still three modes to be supported in MPEG4, and each seems quite different.  Is there any reference, in which condition, which mode should be enabled?  Or all the three modes should be enabled for mobile use?
Thanks
Ken
-----Original Message-----
From: Rob Koenen [mailto:rkoenen   intertrust.com]
Sent: 2002?6?11? 1:18
To: 'Chen, Kenny'; M4IF FORUM
Subject: RE: [M4IF Technotes] question on error resilience for simple prof ile
Using the error resilience tools is always optional,
because behavior in the face of errors is not 
normatively defined.
The tools are in Simple Profile because Simple was
designed for mobile use. 
Other people than me will be able to explain that 
implementation of these tools does not need to 
be too onerous.
Rob
-----Original Message-----
From: Chen, Kenny [mailto:kenny.chen   intel.com]
Sent: Monday, June 10, 2023 1:32
To: M4IF FORUM
Subject: [M4IF Technotes] question on error resilience for simple profile
Hi,
In ISO/IEC 14496-2:2001(E), Table 9-1, for simple profile, all three mode of error resilience should be enabled. (slice resynchronization, data partitioning, RVLC).  This will add much more complexity for the decoder.  I don't understand why should them be included only for simple profile?  That's to say, is that every decoder which claim to support simple profile should support all error resilience modes?
Regards
Ken 
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