[M4IF Technotes] hi

[G Chandra Sekhar Reddy]

Dear All,
> > 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)

As I understand your question, you are talking about VOP sizes (size in
number of bits) and VideoPacket sizes (size in number of bits) being
constant.
The Levels restrict maximum number of bits per VideoPacket, making these
synchronization points appear within some fixed interval (interval in bits,
in bitstream).
This is only restriction on the maximum size. The actual sizes (thereby
synchronization intervals) can be less than this maximum size.
If you want fixed size (thereby fixed synchronization intervals), you can
use stuffing.
About the legal interval you are taking about, I think only restriction is
that they shall be at BYTE-Boundaries.
Does the standard restrict VOP size in bits to some maximum value in any
Profile / Level?
Chandra
**********************************************************************
Chandra Sekhar Reddy G.,
TATA ELXSI Ltd.,
WhiteField Road, Hoody,
BANGALORE, INDIA - 560048.
TEL: +91-80-8410148, 8411811, 8411812 (Ext:254),
FAX: +91-80-8410152, 8411813.
EMAIL: gchandra   tataelxsi.co.in
WEB: www.tataelxsi.com
**********************************************************************
----- Original Message -----
From: Jani Huoponen <Jani.Huoponen   hantro.com>
To: Sudhakar Rao Kimidi <sudhakar   cradle.com>; <technotes   lists.m4if.org>
Sent: Thursday, September 13, 2023 9:25 PM
Subject: RE: [M4IF Technotes] hi
> Dear Sudhakar,
>
> > 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?
>
> Type 2.
>
> > Are both methods of Quantizations used in MPEG-4 Video simple profile?
>
> No. Type 1 (quantization matrices) is not used in 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)
>
> If you mean that should encoded VOPs have a fixed time interval between
them
> then the answer is yes. Simple profile supports this. See section 6.3.3.
in
> the 14496-2 standard, the field called "fixed_vop_rate" explains how this
> works. It is not a compulsory method, i.e., VOPs can have variable time
> intervals between them.
>
> BR, Jani
>
> ------------------------------------------------------------
> Jani Huoponen
> Engineering Manager, System Design
> Hantro Products Oy
> Nahkatehtaankatu 2, 90100 Oulu, Finland
> +358-40-5272676
> ------------------------------------------------------------
>
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