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Code Issues Releases Activity

avoid i++ in decode_block()

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Originally committed as revision 5238 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2006-03-29 09:13:43 +00:00
parent 7d2b787daa
commit 415365d225
1 changed files with 22 additions and 13 deletions
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35
libavcodec/mjpeg.c
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@ -894,14 +894,24 @@ typedef struct MJpegDecodeContext {
static int mjpeg_decode_dht(MJpegDecodeContext *s);
static int build_vlc(VLC *vlc, const uint8_t *bits_table, const uint8_t *val_table,
int nb_codes, int use_static)
int nb_codes, int use_static, int is_ac)
{
uint8_t huff_size[256];
uint16_t huff_code[256];
uint8_t huff_size[256+16];
uint16_t huff_code[256+16];
assert(nb_codes <= 256);
memset(huff_size, 0, sizeof(huff_size));
build_huffman_codes(huff_size, huff_code, bits_table, val_table);
if(is_ac){
memmove(huff_size+16, huff_size, sizeof(uint8_t)*nb_codes);
memmove(huff_code+16, huff_code, sizeof(uint16_t)*nb_codes);
memset(huff_size, 0, sizeof(uint8_t)*16);
memset(huff_code, 0, sizeof(uint16_t)*16);
nb_codes += 16;
}
return init_vlc(vlc, 9, nb_codes, huff_size, 1, 1, huff_code, 2, 2, use_static);
}
@ -930,10 +940,10 @@ static int mjpeg_decode_init(AVCodecContext *avctx)
s->first_picture = 1;
s->org_height = avctx->coded_height;
build_vlc(&s->vlcs[0][0], bits_dc_luminance, val_dc_luminance, 12, 0);
build_vlc(&s->vlcs[0][1], bits_dc_chrominance, val_dc_chrominance, 12, 0);
build_vlc(&s->vlcs[1][0], bits_ac_luminance, val_ac_luminance, 251, 0);
build_vlc(&s->vlcs[1][1], bits_ac_chrominance, val_ac_chrominance, 251, 0);
build_vlc(&s->vlcs[0][0], bits_dc_luminance, val_dc_luminance, 12, 0, 0);
build_vlc(&s->vlcs[0][1], bits_dc_chrominance, val_dc_chrominance, 12, 0, 0);
build_vlc(&s->vlcs[1][0], bits_ac_luminance, val_ac_luminance, 251, 0, 1);
build_vlc(&s->vlcs[1][1], bits_ac_chrominance, val_ac_chrominance, 251, 0, 1);
if (avctx->flags & CODEC_FLAG_EXTERN_HUFF)
{
@ -1084,7 +1094,7 @@ static int mjpeg_decode_dht(MJpegDecodeContext *s)
free_vlc(&s->vlcs[class][index]);
dprintf("class=%d index=%d nb_codes=%d\n",
class, index, code_max + 1);
if(build_vlc(&s->vlcs[class][index], bits_table, val_table, code_max + 1, 0) < 0){
if(build_vlc(&s->vlcs[class][index], bits_table, val_table, code_max + 1, 0, class > 0) < 0){
return -1;
}
}
@ -1262,16 +1272,16 @@ static int decode_block(MJpegDecodeContext *s, DCTELEM *block,
block[0] = val;
/* AC coefs */
ac_vlc = &s->vlcs[1][ac_index];
i = 1;
i = 0;
OPEN_READER(re, &s->gb)
for(;;) {
UPDATE_CACHE(re, &s->gb);
GET_VLC(code, re, &s->gb, s->vlcs[1][ac_index].table, 9, 2)
/* EOB */
if (code == 0)
if (code == 0x10)
break;
if (code == 0xf0) {
if (code == 0x100) {
i += 16;
} else {
i += ((unsigned)code) >> 4;
@ -1293,8 +1303,7 @@ static int decode_block(MJpegDecodeContext *s, DCTELEM *block,
}
j = s->scantable.permutated[i];
block[j] = level * quant_matrix[j];
i++;
if (i >= 64)
if (i >= 63)
break;
}
}