[libdv-dev] Re: libdv DCT MMX routines

[Charles 'B. K. <kr...@cs...>]

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Hi Brent,

It has been a very long time since I looked at that, but I do still
have some notes.

Here are some of the references I used:

   Using MMX[tm] Instructions in a Fast iDCT Algorithm for MPEG decoding
   Intel application note, 2000

   A comparison of fast inverse discreet cosine transform algorithms
   Andy C. Hung and Terese H.-Y. Meng
   Multimedia Systems (1994) 2:204-217

   Direct conversions between DV Format DCT and Ordinary DCT
   Neri Merhav
   HP Laboratories Israel
   HPL-98-140
   August, 1998

As I recall, the multimedia systems paper was very helpful to me in
understanding the algorithms.

- -- Buck

Brent Casavant wrote:

>Peter and Charles,
>
>I noticed that the two of you have been heavily involved with the
>low-level encoder/decoder routines in libdv, the DCT/IDCT code in
>particular, and in Peter's case the MMX routines even more particularly.
>
>I would like to add support for equivalent DCT/IDCT routines using
>Itanium SIMD instructions (similar to x86 MMX). However, to do so
>I need a better understanding of the algorithm implemented by the
>x86 MMX routines. While I can certainly inspect the MMX routines
>and work from there, that is one of the least preferable methods,
>as I believe a higher-level understanding may allow me to create
>routines better suited for Itanium.
>
>Could you direct me toward whatever source material (papers, etc)
>you used in writing the MMX routines?
>
>Thank you,
>Brent Casavant
>

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