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avcodec/vc1_block: Optimize vc1_decode_i_block() 

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
zhaoxiu.zeng 2015-02-25 00:28:45 +08:00 committed by Michael Niedermayer
parent 80a0daa0f6
commit 21581182ca
1 changed files with 38 additions and 57 deletions
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95
libavcodec/vc1_block.c
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@ -555,7 +555,7 @@ static int vc1_decode_i_block(VC1Context *v, int16_t block[64], int n,
int i;
int16_t *dc_val;
int16_t *ac_val, *ac_val2;
int dcdiff;
int dcdiff, scale;
/* Get DC differential */
if (n < 4) {
@ -584,27 +584,29 @@ static int vc1_decode_i_block(VC1Context *v, int16_t block[64], int n,
*dc_val = dcdiff;
/* Store the quantized DC coeff, used for prediction */
if (n < 4) {
block[0] = dcdiff * s->y_dc_scale;
} else {
block[0] = dcdiff * s->c_dc_scale;
}
/* Skip ? */
if (!coded) {
goto not_coded;
}
if (n < 4)
scale = s->y_dc_scale;
else
scale = s->c_dc_scale;
block[0] = dcdiff * scale;
// AC Decoding
i = 1;
ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
ac_val2 = ac_val;
if (dc_pred_dir) // left
ac_val -= 16;
else // top
ac_val -= 16 * s->block_wrap[n];
{
scale = v->pq * 2 + v->halfpq;
//AC Decoding
i = !!coded;
if (coded) {
int last = 0, skip, value;
const uint8_t *zz_table;
int scale;
int k;
scale = v->pq * 2 + v->halfpq;
if (v->s.ac_pred) {
if (!dc_pred_dir)
zz_table = v->zz_8x8[2];
@ -613,13 +615,6 @@ static int vc1_decode_i_block(VC1Context *v, int16_t block[64], int n,
} else
zz_table = v->zz_8x8[1];
ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
ac_val2 = ac_val;
if (dc_pred_dir) // left
ac_val -= 16;
else // top
ac_val -= 16 * s->block_wrap[n];
while (!last) {
vc1_decode_ac_coeff(v, &last, &skip, &value, codingset);
i += skip;
@ -630,13 +625,15 @@ static int vc1_decode_i_block(VC1Context *v, int16_t block[64], int n,
/* apply AC prediction if needed */
if (s->ac_pred) {
int sh;
if (dc_pred_dir) { // left
for (k = 1; k < 8; k++)
block[k << v->left_blk_sh] += ac_val[k];
sh = v->left_blk_sh;
} else { // top
for (k = 1; k < 8; k++)
block[k << v->top_blk_sh] += ac_val[k + 8];
sh = v->top_blk_sh;
ac_val += 8;
}
for (k = 1; k < 8; k++)
block[k << sh] += ac_val[k];
}
/* save AC coeffs for further prediction */
for (k = 1; k < 8; k++) {
@ -652,46 +649,30 @@ static int vc1_decode_i_block(VC1Context *v, int16_t block[64], int n,
block[k] += (block[k] < 0) ? -v->pq : v->pq;
}
if (s->ac_pred) i = 63;
}
} else {
int k;
not_coded:
if (!coded) {
int k, scale;
ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
ac_val2 = ac_val;
i = 0;
scale = v->pq * 2 + v->halfpq;
memset(ac_val2, 0, 16 * 2);
if (dc_pred_dir) { // left
ac_val -= 16;
if (s->ac_pred)
memcpy(ac_val2, ac_val, 8 * 2);
} else { // top
ac_val -= 16 * s->block_wrap[n];
if (s->ac_pred)
memcpy(ac_val2 + 8, ac_val + 8, 8 * 2);
}
/* apply AC prediction if needed */
if (s->ac_pred) {
int sh;
if (dc_pred_dir) { //left
for (k = 1; k < 8; k++) {
block[k << v->left_blk_sh] = ac_val[k] * scale;
if (!v->pquantizer && block[k << v->left_blk_sh])
block[k << v->left_blk_sh] += (block[k << v->left_blk_sh] < 0) ? -v->pq : v->pq;
}
sh = v->left_blk_sh;
} else { // top
for (k = 1; k < 8; k++) {
block[k << v->top_blk_sh] = ac_val[k + 8] * scale;
if (!v->pquantizer && block[k << v->top_blk_sh])
block[k << v->top_blk_sh] += (block[k << v->top_blk_sh] < 0) ? -v->pq : v->pq;
}
sh = v->top_blk_sh;
ac_val += 8;
ac_val2 += 8;
}
memcpy(ac_val2, ac_val, 8 * 2);
for (k = 1; k < 8; k++) {
block[k << sh] = ac_val[k] * scale;
if (!v->pquantizer && block[k << sh])
block[k << sh] += (block[k << sh] < 0) ? -v->pq : v->pq;
}
i = 63;
}
}
if (s->ac_pred) i = 63;
s->block_last_index[n] = i;
return 0;