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ffmpeg
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merge huffman tables so that we read 2 symbols at a time. 30% faster huffyuv decoding. 

Originally committed as revision 9104 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Loren Merritt 2007-05-23 09:02:07 +00:00
parent 5faf2d3641
commit 19716d6478
1 changed files with 52 additions and 7 deletions
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59
libavcodec/huffyuv.c
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@ -70,7 +70,8 @@ typedef struct HYuvContext{
uint64_t stats[3][256];
uint8_t len[3][256];
uint32_t bits[3][256];
VLC vlc[3];
VLC vlc[6]; //Y,U,V,YY,YU,YV
uint16_t pix2_map[3][1<<VLC_BITS];
AVFrame picture;
uint8_t *bitstream_buffer;
unsigned int bitstream_buffer_size;
@ -318,6 +319,35 @@ static void generate_len_table(uint8_t *dst, uint64_t *stats, int size){
}
#endif /* CONFIG_ENCODERS */
static void generate_joint_tables(HYuvContext *s){
// TODO modify init_vlc to allow sparse tables, and eliminate pix2_map
// TODO rgb
if(s->bitstream_bpp < 24){
uint16_t bits[1<<VLC_BITS];
uint8_t len[1<<VLC_BITS];
int p, i, y, u;
for(p=0; p<3; p++){
for(i=y=0; y<256; y++){
int len0 = s->len[0][y];
int limit = VLC_BITS - len0;
if(limit > 0){
for(u=0; u<256; u++){
int len1 = s->len[p][u];
if(len1 <= limit){
len[i] = len0 + len1;
bits[i] = (s->bits[0][y] << len1) + s->bits[p][u];
s->pix2_map[p][i] = (y<<8) + u;
i++;
}
}
}
}
free_vlc(&s->vlc[3+p]);
init_vlc(&s->vlc[3+p], VLC_BITS, i, len, 1, 1, bits, 2, 2, 0);
}
}
}
static int read_huffman_tables(HYuvContext *s, uint8_t *src, int length){
GetBitContext gb;
int i;
@ -339,6 +369,8 @@ printf("%6X, %2d, %3d\n", s->bits[i][j], s->len[i][j], j);
init_vlc(&s->vlc[i], VLC_BITS, 256, s->len[i], 1, 1, s->bits[i], 4, 4, 0);
}
generate_joint_tables(s);
return (get_bits_count(&gb)+7)/8;
}
@ -367,6 +399,8 @@ static int read_old_huffman_tables(HYuvContext *s){
init_vlc(&s->vlc[i], VLC_BITS, 256, s->len[i], 1, 1, s->bits[i], 4, 4, 0);
}
generate_joint_tables(s);
return 0;
#else
av_log(s->avctx, AV_LOG_DEBUG, "v1 huffyuv is not supported \n");
@ -653,16 +687,28 @@ static int encode_init(AVCodecContext *avctx)
}
#endif /* CONFIG_ENCODERS */
/* TODO instead of restarting the read when the code isn't in the first level
* of the joint table, jump into the 2nd level of the individual table. */
#define READ_2PIX(dst0, dst1, plane1){\
int code = get_vlc2(&s->gb, s->vlc[3+plane1].table, VLC_BITS, 1);\
if(code >= 0){\
int x = s->pix2_map[plane1][code];\
dst0 = x>>8;\
dst1 = x;\
}else{\
dst0 = get_vlc2(&s->gb, s->vlc[0].table, VLC_BITS, 3);\
dst1 = get_vlc2(&s->gb, s->vlc[plane1].table, VLC_BITS, 3);\
}\
}
static void decode_422_bitstream(HYuvContext *s, int count){
int i;
count/=2;
for(i=0; i<count; i++){
s->temp[0][2*i ]= get_vlc2(&s->gb, s->vlc[0].table, VLC_BITS, 3);
s->temp[1][ i ]= get_vlc2(&s->gb, s->vlc[1].table, VLC_BITS, 3);
s->temp[0][2*i+1]= get_vlc2(&s->gb, s->vlc[0].table, VLC_BITS, 3);
s->temp[2][ i ]= get_vlc2(&s->gb, s->vlc[2].table, VLC_BITS, 3);
READ_2PIX(s->temp[0][2*i ], s->temp[1][i], 1);
READ_2PIX(s->temp[0][2*i+1], s->temp[2][i], 2);
}
}
@ -672,8 +718,7 @@ static void decode_gray_bitstream(HYuvContext *s, int count){
count/=2;
for(i=0; i<count; i++){
s->temp[0][2*i ]= get_vlc2(&s->gb, s->vlc[0].table, VLC_BITS, 3);
s->temp[0][2*i+1]= get_vlc2(&s->gb, s->vlc[0].table, VLC_BITS, 3);
READ_2PIX(s->temp[0][2*i ], s->temp[0][2*i+1], 0);
}
}