[SCM] libav/experimental: more idct_permute docs

[siretart at users.alioth.debian.org]

The following commit has been merged in the experimental branch:
commit 05493021889a6d226791aa2eb412de7becad2ace
Author: Michael Niedermayer <michaelni at gmx.at>
Date:   Sun May 11 10:19:05 2003 +0000

    more idct_permute docs
    
    Originally committed as revision 1852 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/libavcodec/dsputil.h b/libavcodec/dsputil.h
index 8643e9a..138e6f4 100644
--- a/libavcodec/dsputil.h
+++ b/libavcodec/dsputil.h
@@ -240,6 +240,10 @@ typedef struct DSPContext {
     
     /**
      * idct input permutation.
+     * several optimized IDCTs need a permutated input (relative to the normal order of the reference
+     * IDCT)
+     * this permutation must be performed before the idct_put/add, note, normally this can be merged
+     * with the zigzag/alternate scan<br>
      * an example to avoid confusion:
      * - (->decode coeffs -> zigzag reorder -> dequant -> reference idct ->...)
      * - (x -> referece dct -> reference idct -> x)

-- 
Libav/FFmpeg packaging