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authorMichael Niedermayer <michaelni@gmx.at>2006-03-29 09:13:43 +0000
committerMichael Niedermayer <michaelni@gmx.at>2006-03-29 09:13:43 +0000
commit415365d225a20014f517e110cfe8b91f3a3fb76f (patch)
treebe2f9931da231e85faf9f3f2945943d80784044a /libavcodec/mjpeg.c
parent7d2b787daa8237480cee619e3d22bd6cf9740db4 (diff)
downloadffmpeg-415365d225a20014f517e110cfe8b91f3a3fb76f.tar.gz
avoid i++ in decode_block()
Originally committed as revision 5238 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/mjpeg.c')
-rw-r--r--libavcodec/mjpeg.c35
1 files changed, 22 insertions, 13 deletions
diff --git a/libavcodec/mjpeg.c b/libavcodec/mjpeg.c
index 79caa9bf7b..f0634a0413 100644
--- a/libavcodec/mjpeg.c
+++ b/libavcodec/mjpeg.c
@@ -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;
}
}