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Coalescing the un-weighting and de-quantization steps for faster

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processing

Originally committed as revision 14691 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Roman Shaposhnik 2008-08-11 09:35:58 +00:00
parent 76c655fb8f
commit d557838cfb
2 changed files with 19 additions and 51 deletions
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47
libavcodec/dv.c
View File

@ -50,7 +50,7 @@ typedef struct DVVideoContext {
uint8_t *buf;
uint8_t dv_zigzag[2][64];
uint8_t dv_idct_shift[2][2][22][64];
uint32_t dv_idct_factor[2][2][22][64];
void (*get_pixels)(DCTELEM *block, const uint8_t *pixels, int line_size);
void (*fdct[2])(DCTELEM *block);
@ -84,25 +84,22 @@ static struct dv_vlc_pair {
static void dv_build_unquantize_tables(DVVideoContext *s, uint8_t* perm)
{
int i, q, j;
int i, q, a;
/* NOTE: max left shift is 6 */
for(q = 0; q < 22; q++) {
/* 88DCT */
for(i = 1; i < 64; i++) {
/* 88 table */
j = perm[i];
s->dv_idct_shift[0][0][q][j] =
dv_quant_shifts[q][dv_88_areas[i]] + 1;
s->dv_idct_shift[1][0][q][j] = s->dv_idct_shift[0][0][q][j] + 1;
}
i=1;
for(a = 0; a<4; a++) {
for(; i < dv_quant_areas[a]; i++) {
/* 88 table */
s->dv_idct_factor[0][0][q][i] = dv_iweight_88[i]<<(dv_quant_shifts[q][a] + 1);
s->dv_idct_factor[1][0][q][i] = s->dv_idct_factor[0][0][q][i]<<1;
/* 248DCT */
for(i = 1; i < 64; i++) {
/* 248 table */
s->dv_idct_shift[0][1][q][i] =
dv_quant_shifts[q][dv_248_areas[i]] + 1;
s->dv_idct_shift[1][1][q][i] = s->dv_idct_shift[0][1][q][i] + 1;
/* 248 table */
s->dv_idct_factor[0][1][q][i] = dv_iweight_248[i]<<(dv_quant_shifts[q][a] + 1);
s->dv_idct_factor[1][1][q][i] = s->dv_idct_factor[0][1][q][i]<<1;
}
}
}
}
@ -247,9 +244,8 @@ static av_cold int dvvideo_init(AVCodecContext *avctx)
// #define printf(...) av_log(NULL, AV_LOG_ERROR, __VA_ARGS__)
typedef struct BlockInfo {
const uint8_t *shift_table;
const uint32_t *factor_table;
const uint8_t *scan_table;
const int *iweight_table;
uint8_t pos; /* position in block */
uint8_t dct_mode;
uint8_t partial_bit_count;
@ -281,11 +277,10 @@ static void dv_decode_ac(GetBitContext *gb, BlockInfo *mb, DCTELEM *block)
{
int last_index = gb->size_in_bits;
const uint8_t *scan_table = mb->scan_table;
const uint8_t *shift_table = mb->shift_table;
const int *iweight_table = mb->iweight_table;
const uint32_t *factor_table = mb->factor_table;
int pos = mb->pos;
int partial_bit_count = mb->partial_bit_count;
int level, pos1, run, vlc_len, index;
int level, run, vlc_len, index;
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
@ -330,13 +325,8 @@ static void dv_decode_ac(GetBitContext *gb, BlockInfo *mb, DCTELEM *block)
if (pos >= 64)
break;
pos1 = scan_table[pos];
level <<= shift_table[pos1];
/* unweigh, round, and shift down */
level = (level*iweight_table[pos] + (1 << (dv_iweight_bits-1))) >> dv_iweight_bits;
block[pos1] = level;
level = (level*factor_table[pos] + (1 << (dv_iweight_bits-1))) >> dv_iweight_bits;
block[scan_table[pos]] = level;
UPDATE_CACHE(re, gb);
}
@ -402,9 +392,8 @@ static inline void dv_decode_video_segment(DVVideoContext *s,
dct_mode = get_bits1(&gb);
mb->dct_mode = dct_mode;
mb->scan_table = s->dv_zigzag[dct_mode];
mb->iweight_table = dct_mode ? dv_iweight_248 : dv_iweight_88;
class1 = get_bits(&gb, 2);
mb->shift_table = s->dv_idct_shift[class1 == 3][dct_mode]
mb->factor_table = s->dv_idct_factor[class1 == 3][dct_mode]
[quant + dv_quant_offset[class1]];
dc = dc << 2;
/* convert to unsigned because 128 is not added in the

23
libavcodec/dvdata.h
View File

@ -286,28 +286,6 @@ static const uint8_t dv_vlc_level[409] = {
};
/* unquant tables (not used directly) */
static const uint8_t dv_88_areas[64] = {
0,0,0,1,1,1,2,2,
0,0,1,1,1,2,2,2,
0,1,1,1,2,2,2,3,
1,1,1,2,2,2,3,3,
1,1,2,2,2,3,3,3,
1,2,2,2,3,3,3,3,
2,2,2,3,3,3,3,3,
2,2,3,3,3,3,3,3,
};
static const uint8_t dv_248_areas[64] = {
0,0,1,1,1,2,2,3,
0,0,1,1,2,2,2,3,
0,1,1,2,2,2,3,3,
0,1,1,2,2,2,3,3,
1,1,2,2,2,3,3,3,
1,1,2,2,2,3,3,3,
1,2,2,2,3,3,3,3,
1,2,2,3,3,3,3,3,
};
static const uint8_t dv_quant_shifts[22][4] = {
{ 3,3,4,4 },
{ 3,3,4,4 },
@ -334,6 +312,7 @@ static const uint8_t dv_quant_shifts[22][4] = {
};
static const uint8_t dv_quant_offset[4] = { 6, 3, 0, 1 };
static const uint8_t dv_quant_areas[4] = { 6, 21, 43, 64 };
/* NOTE: I prefer hardcoding the positioning of dv blocks, it is
simpler :-) */