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optimizations by arpi

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Originally committed as revision 5235 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2006-03-29 01:59:24 +00:00
parent 6a1a892f23
commit 22dde0e955
1 changed files with 19 additions and 6 deletions
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25
libavcodec/mjpeg.c
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@ -1246,11 +1246,10 @@ static inline int mjpeg_decode_dc(MJpegDecodeContext *s, int dc_index)
/* decode block and dequantize */
static int decode_block(MJpegDecodeContext *s, DCTELEM *block,
int component, int dc_index, int ac_index, int quant_index)
int component, int dc_index, int ac_index, int16_t *quant_matrix)
{
int code, i, j, level, val;
VLC *ac_vlc;
int16_t *quant_matrix;
/* DC coef */
val = mjpeg_decode_dc(s, dc_index);
@ -1258,15 +1257,16 @@ static int decode_block(MJpegDecodeContext *s, DCTELEM *block,
dprintf("error dc\n");
return -1;
}
quant_matrix = s->quant_matrixes[quant_index];
val = val * quant_matrix[0] + s->last_dc[component];
s->last_dc[component] = val;
block[0] = val;
/* AC coefs */
ac_vlc = &s->vlcs[1][ac_index];
i = 1;
OPEN_READER(re, &s->gb)
for(;;) {
code = get_vlc2(&s->gb, s->vlcs[1][ac_index].table, 9, 2);
UPDATE_CACHE(re, &s->gb);
GET_VLC(code, re, &s->gb, s->vlcs[1][ac_index].table, 9, 2)
if (code < 0) {
dprintf("error ac\n");
@ -1278,8 +1278,19 @@ static int decode_block(MJpegDecodeContext *s, DCTELEM *block,
if (code == 0xf0) {
i += 16;
} else {
level = get_xbits(&s->gb, code & 0xf);
i += code >> 4;
code &= 0xf;
UPDATE_CACHE(re, &s->gb)
if ((int32_t)GET_CACHE(re,&s->gb)<0) { //MSB=1
level = NEG_USR32( GET_CACHE(re,&s->gb),code);
} else {
level = - NEG_USR32(~GET_CACHE(re,&s->gb),code);
}
SKIP_BITS(re, &s->gb, code)
if (i >= 64) {
dprintf("error count: %d\n", i);
return -1;
@ -1291,6 +1302,8 @@ static int decode_block(MJpegDecodeContext *s, DCTELEM *block,
break;
}
}
CLOSE_READER(re, &s->gb)
return 0;
}
@ -1467,7 +1480,7 @@ static int mjpeg_decode_scan(MJpegDecodeContext *s){
memset(s->block, 0, sizeof(s->block));
if (decode_block(s, s->block, i,
s->dc_index[i], s->ac_index[i],
s->quant_index[c]) < 0) {
s->quant_matrixes[ s->quant_index[c] ]) < 0) {
dprintf("error y=%d x=%d\n", mb_y, mb_x);
return -1;
}