[Mp4-tech] ideal rate control algorithm

[Zhenzhong CHEN]

Hi Satendra,
My two cents:
The fundamental problem in rate control can be stated as follows:
min D, subject to: R < R_max
This objective can be further specified as either minimizing average distortion (MINAVE) or minimizing maximum distortion (MINMAX) of the video sequence.  
However, ideal (or optimal) rate control depends on your requirements. 
>From the bit rate point of view, we can classify the video coding applications into two categories: constant bit rate (CBR) and variable bit rate (VBR). As Bharat have described, the possible scenarios for rate control are: constant bitrate based, variable bitrate based, a mix of CBR and VBR based (sometimes involved in the first scenario).

>From the constraint point of view, for end-to-end real-time video communication systems, there is delay constraint to avoid delay jitter and jerky motion. For constant bit-rate applications, buffer constraint is introduced. For storage video applications, the budget constraint should be considered since the storage space is fixed.

Different application has different computational complexity requirement.  
So how can we build the ideal rate control that depends on above requiements.  
Regards,
Zhenzhong CHEN
----- Original Message ----- 
From: <kaustubh.patankar vsnl.net>
To: "Bharat P. SONI" <bharat.soni st.com>
Cc: <mp4-tech lists.mpegif.org>
Sent: Thursday, October 07, 2023 8:50 PM
Subject: Re: RE: [Mp4-tech] ideal rate control algorithm
> Dear Satendar,
> 
> I have few inputs.
> 
> Please check the algorithm to refer for interlaced and progressive sequences. Please refer to TM5 rate control model for inplementation of the algorithms.
> The rate control can be classified as
> 1. VBR with may be a specified band for variation where the average bit-rate is important. Ultimately the file size can depend on the average bit rate.
> 2. the purpose of VBR is to allocate maximum bit rate for the complex sequences
> 3. There are multi pass VBR implementations also avaialbles.
> 4. regarding the CBR, the purpose can be to achieve constant bit rate with variation in Q parameter over macro block.
> 
> I think this may be helpful
> 
> Kaustubh
> 
> ----- Original Message -----
> From: "Bharat P. SONI" <bharat.soni st.com>
> Date: Thursday, October 7, 2023 11:47 am
> Subject: RE: [Mp4-tech] ideal rate control algorithm
> 
> > Hi Satendra,
> > 
> > The ideal rate control algorithm, I would say practically does not 
> > exist. It
> > is dependent on the requirements. If you define your requirements 
> > and if an
> > algorithm meets your requirement then I would call it an ideal 
> > algorithm.There are three possible scenarios,
> > 1 constant bitrate: bitrate is constant through out the sequence (the
> > quality may vary).
> > 2 Variable bitrate: bitrate varies over the sequence based on the 
> > videocomplexity, but the quality is maintained at same level.
> > 3 A mix of CBR and VBR: In this case one can allow to vary the 
> > bitrate over
> > small duration of sequence but the overall bitrate is controlled and
> > averaged out to be a constant. In this case the quality is better 
> > than CBR.
> > 
> > Regards,
> > bharat
> > 
> > -----Original Message-----
> > From: mp4-tech-bounces lists.mpegif.org
> > [mp4-tech-bounces lists.mpegif.org] On Behalf Of Satendra
> > Sent: Wednesday, October 06, 2023 4:47 PM
> > To: mp4-tech lists.mpegif.org
> > Subject: [Mp4-tech] ideal rate control algorithm
> > 
> > 
> > hi,
> > 
> > I am working on rate control for MPEG-2.  I want to know what 
> > should be the
> > characteristics of  an ideal rate control algorithm?  and how can 
> > we build
> > that?
> > 
> > 
> > Thanx
> > _______________________________________________
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