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avcodec/vc1_block: Optimize vc1_decode_i_block_adv()

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9127 -> 8936 decicycles (fate-suite/vc1/SA10143.vc1)
13855 -> 10976 decicycles  (fate-suite/vc1/SA20021.vc1)
tests done by the author over this function but with the whole
patchset applied not just this commit

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
pull/117/head
zhaoxiu.zeng 10 years ago committed by Michael Niedermayer
parent 21581182ca
commit 94f5ac93d7
1 changed files with 53 additions and 71 deletions
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  1. 124
      libavcodec/vc1_block.c

124
libavcodec/vc1_block.c
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@ -729,39 +729,42 @@ static int vc1_decode_i_block_adv(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;
}
//AC Decoding
i = 1;
if (n < 4)
scale = s->y_dc_scale;
else
scale = s->c_dc_scale;
block[0] = dcdiff * scale;
/* check if AC is needed at all */
if (!a_avail && !c_avail)
use_pred = 0;
ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
ac_val2 = ac_val;
scale = mquant * 2 + ((mquant == v->pq) ? v->halfpq : 0);
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];
q1 = s->current_picture.qscale_table[mb_pos];
if ( dc_pred_dir && c_avail && mb_pos)
q2 = s->current_picture.qscale_table[mb_pos - 1];
if (!dc_pred_dir && a_avail && mb_pos >= s->mb_stride)
q2 = s->current_picture.qscale_table[mb_pos - s->mb_stride];
if ( dc_pred_dir && n == 1)
q2 = q1;
if (!dc_pred_dir && n == 2)
q2 = q1;
if (n == 3)
q2 = q1;
else if (dc_pred_dir) {
if (n == 1)
q2 = q1;
else if (c_avail && mb_pos)
q2 = s->current_picture.qscale_table[mb_pos - 1];
} else {
if (n == 2)
q2 = q1;
else if (a_avail && mb_pos >= s->mb_stride)
q2 = s->current_picture.qscale_table[mb_pos - s->mb_stride];
}
//AC Decoding
i = 1;
if (coded) {
int last = 0, skip, value;
@ -794,28 +797,24 @@ static int vc1_decode_i_block_adv(VC1Context *v, int16_t block[64], int n,
/* apply AC prediction if needed */
if (use_pred) {
int sh;
if (dc_pred_dir) { // left
sh = v->left_blk_sh;
} else { // top
sh = v->top_blk_sh;
ac_val += 8;
}
/* scale predictors if needed*/
if (q2 && q1 != q2) {
q1 = q1 * 2 + ((q1 == v->pq) ? v->halfpq : 0) - 1;
q2 = q2 * 2 + ((q2 == v->pq) ? v->halfpq : 0) - 1;
if (q1 < 1)
return AVERROR_INVALIDDATA;
if (dc_pred_dir) { // left
for (k = 1; k < 8; k++)
block[k << v->left_blk_sh] += (ac_val[k] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18;
} else { // top
for (k = 1; k < 8; k++)
block[k << v->top_blk_sh] += (ac_val[k + 8] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18;
}
q2 = q2 * 2 + ((q2 == v->pq) ? v->halfpq : 0) - 1;
for (k = 1; k < 8; k++)
block[k << sh] += (ac_val[k] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18;
} else {
if (dc_pred_dir) { //left
for (k = 1; k < 8; k++)
block[k << v->left_blk_sh] += ac_val[k];
} else { //top
for (k = 1; k < 8; k++)
block[k << v->top_blk_sh] += ac_val[k + 8];
}
for (k = 1; k < 8; k++)
block[k << sh] += ac_val[k];
}
}
/* save AC coeffs for further prediction */
@ -832,55 +831,38 @@ static int vc1_decode_i_block_adv(VC1Context *v, int16_t block[64], int n,
block[k] += (block[k] < 0) ? -mquant : mquant;
}
if (use_pred) i = 63;
} else { // no AC coeffs
int k;
memset(ac_val2, 0, 16 * 2);
if (dc_pred_dir) { // left
if (use_pred) {
memcpy(ac_val2, ac_val, 8 * 2);
if (q2 && q1 != q2) {
q1 = q1 * 2 + ((q1 == v->pq) ? v->halfpq : 0) - 1;
q2 = q2 * 2 + ((q2 == v->pq) ? v->halfpq : 0) - 1;
if (q1 < 1)
return AVERROR_INVALIDDATA;
for (k = 1; k < 8; k++)
ac_val2[k] = (ac_val2[k] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18;
}
}
} else { // top
if (use_pred) {
memcpy(ac_val2 + 8, ac_val + 8, 8 * 2);
if (q2 && q1 != q2) {
q1 = q1 * 2 + ((q1 == v->pq) ? v->halfpq : 0) - 1;
q2 = q2 * 2 + ((q2 == v->pq) ? v->halfpq : 0) - 1;
if (q1 < 1)
return AVERROR_INVALIDDATA;
for (k = 1; k < 8; k++)
ac_val2[k + 8] = (ac_val2[k + 8] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18;
}
}
}
/* apply AC prediction if needed */
if (use_pred) {
int sh;
if (dc_pred_dir) { // left
for (k = 1; k < 8; k++) {
block[k << v->left_blk_sh] = ac_val2[k] * scale;
if (!v->pquantizer && block[k << v->left_blk_sh])
block[k << v->left_blk_sh] += (block[k << v->left_blk_sh] < 0) ? -mquant : mquant;
}
sh = v->left_blk_sh;
} else { // top
for (k = 1; k < 8; k++) {
block[k << v->top_blk_sh] = ac_val2[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) ? -mquant : mquant;
}
sh = v->top_blk_sh;
ac_val += 8;
ac_val2 += 8;
}
memcpy(ac_val2, ac_val, 8 * 2);
if (q2 && q1 != q2) {
q1 = q1 * 2 + ((q1 == v->pq) ? v->halfpq : 0) - 1;
q2 = q2 * 2 + ((q2 == v->pq) ? v->halfpq : 0) - 1;
if (q1 < 1)
return AVERROR_INVALIDDATA;
for (k = 1; k < 8; k++)
ac_val2[k] = (ac_val2[k] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18;
}
for (k = 1; k < 8; k++) {
block[k << sh] = ac_val2[k] * scale;
if (!v->pquantizer && block[k << sh])
block[k << sh] += (block[k << sh] < 0) ? -mquant : mquant;
}
i = 63;
}
}
if (use_pred) i = 63;
s->block_last_index[n] = i;
return 0;

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