[M4IF Technotes] Simple Profile Quantisation

[Yossi]

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Hello Sudhakar,
As to your first question, Simple Profile allows only the Second method for
quantisation (quant_type == 0). See Table 9-1 "Tools for Version 1 Visual
Object Types."
Regards,
Yossi
Date: Thu, 13 Sep 2023 15:37:08 +0530
From: Sudhakar Rao Kimidi <sudhakar   cradle.com>
Organization: cradle
To: "'technotes   lists.m4if.org'" <technotes   lists.m4if.org>
Subject: [M4IF Technotes] hi
Dear all,
Can somebody help me with the answers for the following.
1. Which method of Quantization is used in MPEG-4 video simple profile?
Are both methods of Quantizations used in MPEG-4 Video simple profile?
2. Is fixed interval synchronization supported in simple profile? Is it
compulsory to use the method? Is there any mentioning about it in
syntax?(This method requires that VOP start codes and resynchronization
markers appear only at legal fixed interval locations in the bitstream)
Thanks,
Sudhakar K.
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Message: 2
Date: Wed, 12 Sep 2023 15:07:46 -0700
From: Eugene Mar <gmar   cvs.agilent.com>
Organization: Agilent Technologies
To: technotes   lists.m4if.org
Subject: [M4IF Technotes] Question on inverse Quantization
Hello,
I have a question concerning an apparent discrepency between the ISO/IEC
14496-2 Standards Document, the ISO/IEC JTC1/SC29/WG11 N3908 VM
Document, and the reference software from MoMuSys and Microsoft.
On section 7.4.4.1.2 of the ISO/IEC 14496-2 Standards Document, the
equation for F''[v][u] is shown with a divisor of 16 if QF[v][u] != 0.
On section 7.4.4.6 of the ISO/IEC 14496-2 Standards Document, the sample
c-code shows F''[v][u] with a divisor of 32.
On section 3.4.5.4.1 of the N3908 VM Document, the equation for
F''[v][u] is shown to be divided by 32.
On section 3.4.5.7 of the N3908 VM Document, the sample c-code shows
F''[v][u] with a divisor of 32.
Both reference c-code from MoMySys and Microsoft shows F''[v][u] with a
divisor of 16. On MoMuSys the code comes from
vm_common\src\text_quant.c. On Microsoft the code comes from
sys\encoder\blkenc.cpp.
My question is, is the divisor for F''[v][u] 16 or 32?
Sincerely,
Gene Mar
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