Re: clean implementation

OO it's a very nice idea, anyway we really never managed to do that,
in 14496/2. Anyway I'm looking forward to seeing what you will do... :)
For optimizations... why don't you use namespaces?
One decides for examples to have SAD functions, than implements
SADMMX, SADSSE, SADNOASM, SADSWAR (guess what it is?)
and then defines SAD to be one of the namespaces depending on the
architecture. Neat, in my opinion.
(namespace could be replaced by structs with static members)
And then you could have a "magic" namespace SADMMXORSSE with
pointer to functions instead of functions....
Have Fun.
Luca.

  ----- Original Message ----- 
  From: Aitor Garay 
  To: [email protected] 
  Sent: Wednesday, March 26, 2003 10:40 AM
  Subject: [Hdot264-devel] clean implementation



      I agree with the comments made by Luca, Char, shlezman and others.  A clean
  implementation should be started.  My initial suggestion of a Java implementation
  could not be a good idea as much of you said.  Main reasons are that people are
  not mainly interested in a testing/research tool but want a real and practical
  implementation.

      Starting a clean implementation in C/C++ is not going to be an easy task, and
  as some said and i subscribe, much of us have other important dutties to do all over
  the week.  I believe that what is need is an initial framework where start hacking
  into.  Once that code critical mass has been surpassed everything should follow.

      I propose the following:

      -    language of choice: C++.  With this i mean different things.  I mean a real
  OO implementation, not just a bunch of code packed in a single class.  I don't mean
  a pure OO extremely fine grained implemenation where everything is a class.  We
  want a clean implementation, but a real and efficient one also.  So nothing of creating
  objects unnecessary.  A good OO architecture will allow further optimizations ( for
  example, replacing/subclassing a "transform" class to use MMX/AltiVec).

      A nice starting milestone could be to get to a more or less full functional codec
  that only makes use of intra pictures.  For this, the following things must be
  implemented:

      -    intra predictor
      -    transform and quantize
      -    CAVLC
      -    bit stream parse/generation
      -    deblocking filter ( optional at the begining)

      Then, as shlezman stated, we could go for the following:

      -    P, B frames
      -    multiple reference frames
      -    CABAC
      -    rate-distortion optimization
      -    ...

      I already have been working on intra prediction and T/Q and could start contributing
  in that aspect.  Well, i also have some ideas of what a clean and efficient OO framework
  could be.

      /AITOR
    ----- Original Message ----- 
    From: [email protected] 
    To: [email protected] 
    Sent: Wednesday, March 26, 2003 9:27 AM
    Subject: RE: [Hdot264-devel] project extension proposal 


          Hi all,

          I'd like to enforce Luca's opinion. The H.264 decoder can deliver great performance (even without much assembly work) for as long as it has nothing to do with the RS and I strongly believe that this is correct for the encoder as well. Playing around with "working code" and optimizing bits here and there can last forever and never deliver the desired results.

          A new, simple, basic and generic design is required (even OO). Milestones must be defined, for example:

          Stage 1 - baseline profile encoder/decoder

          Stage 2 - Add B frames, improve motion estimation algorithms, and begin assembly work

          Stage 3 - add CABAC , RD optimizations

          Once these points are defined the "real" work can be started. As for clean code for algorithmic work, the RS is good enough for that purpose, maintaining three versions of the same code is really unnecessary. There's a jvt group that dose that thing exactly and delivers results.


         


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