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Adjust AC prediction if (some) predictors are not available.

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Originally committed as revision 5564 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Kostya Shishkov
2006-07-01 07:22:29 +00:00
parent e9f2396e6f
commit 8f8d0e4875
1 changed files with 14 additions and 13 deletions
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27
libavcodec/vc1.c
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@@ -1892,6 +1892,7 @@ static int vc1_decode_intra_block(VC1Context *v, DCTELEM block[64], int n, int c
const int8_t *zz_table;
int scale;
int k;
int use_pred = s->ac_pred;
scale = mquant * 2;
@@ -1899,6 +1900,10 @@ static int vc1_decode_intra_block(VC1Context *v, DCTELEM block[64], int n, int c
ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
ac_val2 = ac_val;
if(!a_avail) dc_pred_dir = 1;
if(!c_avail) dc_pred_dir = 0;
if(!a_avail && !c_avail) use_pred = 0;
if(dc_pred_dir) //left
ac_val -= 16;
else //top
@@ -1913,7 +1918,7 @@ static int vc1_decode_intra_block(VC1Context *v, DCTELEM block[64], int n, int c
}
/* apply AC prediction if needed */
if(s->ac_pred && (v->a_avail || v->c_avail)) {
if(use_pred) {
/* scale predictors if needed*/
int mb_pos2, q1, q2;
@@ -1921,14 +1926,6 @@ static int vc1_decode_intra_block(VC1Context *v, DCTELEM block[64], int n, int c
q1 = s->current_picture.qscale_table[mb_pos];
q2 = s->current_picture.qscale_table[mb_pos2];
if(!c_avail) {
memset(ac_val, 0, 8 * sizeof(ac_val[0]));
dc_pred_dir = 0;
}
if(!a_avail) {
memset(ac_val + 8, 0, 8 * sizeof(ac_val[0]));
dc_pred_dir = 1;
}
if(q2 && q1 != q2) {
q1 = q1 * 2 - 1;
q2 = q2 * 2 - 1;
@@ -1964,12 +1961,14 @@ static int vc1_decode_intra_block(VC1Context *v, DCTELEM block[64], int n, int c
block[k] += (block[k] < 0) ? -mquant : mquant;
}
if(s->ac_pred) i = 63;
if(use_pred) i = 63;
}
not_coded:
if(!coded) {
int k, scale;
int use_pred = s->ac_pred;
ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
ac_val2 = ac_val;
@@ -1982,20 +1981,22 @@ not_coded:
dc_pred_dir = 1;
}
if(!a_avail && !c_avail) use_pred = 0;
scale = mquant * 2;
memset(ac_val2, 0, 16 * 2);
if(dc_pred_dir) {//left
ac_val -= 16;
if(s->ac_pred && (v->a_avail || v->c_avail))
if(use_pred)
memcpy(ac_val2, ac_val, 8 * 2);
} else {//top
ac_val -= 16 * s->block_wrap[n];
if(s->ac_pred && (v->a_avail || v->c_avail))
if(use_pred)
memcpy(ac_val2 + 8, ac_val + 8, 8 * 2);
}
/* apply AC prediction if needed */
if(s->ac_pred && (v->a_avail || v->c_avail)) {
if(use_pred) {
if(dc_pred_dir) { //left
for(k = 1; k < 8; k++) {
block[k << 3] = ac_val[k] * scale;