[SCM] libav/experimental: Use memset to set the runs partially coded superblocks

[siretart at users.alioth.debian.org]

The following commit has been merged in the experimental branch:
commit 33dbc1b7ca4bf8679079e1fede69dde92abf4d19
Author: David Conrad <lessen42 at gmail.com>
Date:   Sun Feb 21 00:10:47 2010 +0000

    Use memset to set the runs partially coded superblocks
    
    Much faster for long runs (e.g. nearly uncoded frames), slightly faster
    for the general case.
    
    Originally committed as revision 21927 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/libavcodec/vp3.c b/libavcodec/vp3.c
index 59698d2..9268d5e 100644
--- a/libavcodec/vp3.c
+++ b/libavcodec/vp3.c
@@ -461,17 +461,21 @@ static int unpack_superblocks(Vp3DecodeContext *s, GetBitContext *gb)
 
         /* unpack the list of partially-coded superblocks */
         bit = get_bits1(gb);
-        /* toggle the bit because as soon as the first run length is
-         * fetched the bit will be toggled again */
-        bit ^= 1;
         while (current_superblock < s->superblock_count) {
-            if (current_run-- == 0) {
-                bit ^= 1;
                 current_run = get_vlc2(gb,
-                    s->superblock_run_length_vlc.table, 6, 2);
-                if (current_run == 33)
+                    s->superblock_run_length_vlc.table, 6, 2) + 1;
+                if (current_run == 34)
                     current_run += get_bits(gb, 12);
 
+            if (current_superblock + current_run > s->superblock_count) {
+                av_log(s->avctx, AV_LOG_ERROR, "Invalid partially coded superblock run length\n");
+                return -1;
+            }
+
+            memset(s->superblock_coding + current_superblock, bit, current_run);
+
+            current_superblock += current_run;
+
                 /* if any of the superblocks are not partially coded, flag
                  * a boolean to decode the list of fully-coded superblocks */
                 if (bit == 0) {
@@ -482,8 +486,8 @@ static int unpack_superblocks(Vp3DecodeContext *s, GetBitContext *gb)
                      * superblocks */
                     decode_partial_blocks = 1;
                 }
-            }
-            s->superblock_coding[current_superblock++] = bit;
+
+                bit ^= 1;
         }
 
         /* unpack the list of fully coded superblocks if any of the blocks were

-- 
Libav/FFmpeg packaging