generic-library/ffmpeg
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Use memset to set the runs partially coded superblocks

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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
This commit is contained in:
David Conrad 2010-02-21 00:10:47 +00:00
parent bbdf0d2214
commit 33dbc1b7ca
1 changed files with 13 additions and 9 deletions
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22
libavcodec/vp3.c
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@ -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