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Add a seperate VLC table for progressive jpeg so we dont have to subtract 16 in the inner loop.

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Originally committed as revision 25545 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2010-10-21 22:44:41 +00:00
parent 8870b25140
commit 5675a11f92
2 changed files with 12 additions and 7 deletions
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17
libavcodec/mjpegdec.c
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@ -69,6 +69,10 @@ static void build_basic_mjpeg_vlc(MJpegDecodeContext * s) {
ff_mjpeg_val_ac_luminance, 251, 0, 1);
build_vlc(&s->vlcs[1][1], ff_mjpeg_bits_ac_chrominance,
ff_mjpeg_val_ac_chrominance, 251, 0, 1);
build_vlc(&s->vlcs[2][0], ff_mjpeg_bits_ac_luminance,
ff_mjpeg_val_ac_luminance, 251, 0, 0);
build_vlc(&s->vlcs[2][1], ff_mjpeg_bits_ac_chrominance,
ff_mjpeg_val_ac_chrominance, 251, 0, 0);
}
av_cold int ff_mjpeg_decode_init(AVCodecContext *avctx)
@ -188,6 +192,9 @@ int ff_mjpeg_decode_dht(MJpegDecodeContext *s)
if(build_vlc(&s->vlcs[class][index], bits_table, val_table, code_max + 1, 0, class > 0) < 0){
return -1;
}
if(class>0 && build_vlc(&s->vlcs[2][index], bits_table, val_table, code_max + 1, 0, 0) < 0){
return -1;
}
}
return 0;
}
@ -473,9 +480,8 @@ static int decode_block_progressive(MJpegDecodeContext *s, DCTELEM *block, uint8
{OPEN_READER(re, &s->gb)
for(i=ss;;i++) {
UPDATE_CACHE(re, &s->gb);
GET_VLC(code, re, &s->gb, s->vlcs[1][ac_index].table, 9, 2)
/* Progressive JPEG use AC coeffs from zero and this decoder sets offset 16 by default */
code -= 16;
GET_VLC(code, re, &s->gb, s->vlcs[2][ac_index].table, 9, 2)
run = ((unsigned) code) >> 4;
code &= 0xF;
if(code) {
@ -561,9 +567,8 @@ static int decode_block_refinement(MJpegDecodeContext *s, DCTELEM *block, uint8_
else {
for(;;i++) {
UPDATE_CACHE(re, &s->gb);
GET_VLC(code, re, &s->gb, s->vlcs[1][ac_index].table, 9, 2)
/* Progressive JPEG use AC coeffs from zero and this decoder sets offset 16 by default */
code -= 16;
GET_VLC(code, re, &s->gb, s->vlcs[2][ac_index].table, 9, 2)
if(code & 0xF) {
run = ((unsigned) code) >> 4;
UPDATE_CACHE(re, &s->gb);

2
libavcodec/mjpegdec.h
View File

@ -44,7 +44,7 @@ typedef struct MJpegDecodeContext {
uint8_t *buffer;
int16_t quant_matrixes[4][64];
VLC vlcs[2][4];
VLC vlcs[3][4];
int qscale[4]; ///< quantizer scale calculated from quant_matrixes
int org_height; /* size given at codec init */