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Code Issues Releases Activity

Correct inverse quantization for P-frames

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Originally committed as revision 5760 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Kostya Shishkov 2006-07-16 03:47:34 +00:00
parent c5b32ec1cb
commit 0a45801f8e
1 changed files with 13 additions and 4 deletions
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17
libavcodec/vc1.c
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@ -1331,10 +1331,11 @@ static int vc1_parse_frame_header(VC1Context *v, GetBitContext* gb)
else
v->pq = pquant_table[v->quantizer_mode-1][pqindex];
v->pquantizer = 1;
if (v->quantizer_mode == QUANT_FRAME_IMPLICIT)
v->pquantizer = pqindex < 9;
if (v->quantizer_mode == QUANT_UNIFORM || v->quantizer_mode == QUANT_NON_UNIFORM)
v->pquantizer = v->quantizer_mode == QUANT_UNIFORM;
if (v->quantizer_mode == QUANT_NON_UNIFORM)
v->pquantizer = 0;
v->pqindex = pqindex;
if (pqindex < 9) v->halfpq = get_bits(gb, 1);
else v->halfpq = 0;
@ -2151,7 +2152,7 @@ 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;
scale = mquant * 2;
scale = mquant * 2 + v->halfpq;
if(dc_pred_dir) //left
ac_val -= 16;
@ -2289,7 +2290,7 @@ static int vc1_decode_p_block(VC1Context *v, DCTELEM block[64], int n, int mquan
if(ttblk == TT_8X4_TOP || ttblk == TT_8X4_BOTTOM) ttblk = TT_8X4;
if(ttblk == TT_4X8_RIGHT || ttblk == TT_4X8_LEFT) ttblk = TT_4X8;
}
scale = 2 * mquant;
scale = 2 * mquant + v->halfpq;
// convert transforms like 8X4_TOP to generic TT and SUBBLKPAT
if(ttblk == TT_8X4_TOP || ttblk == TT_8X4_BOTTOM) {
@ -2311,6 +2312,8 @@ static int vc1_decode_p_block(VC1Context *v, DCTELEM block[64], int n, int mquan
break;
idx = vc1_simple_progressive_8x8_zz[i++];
block[idx] = value * scale;
if(!v->pquantizer)
block[idx] += (block[idx] < 0) ? -mquant : mquant;
}
vc1_inv_trans(block, 8, 8);
break;
@ -2326,6 +2329,8 @@ static int vc1_decode_p_block(VC1Context *v, DCTELEM block[64], int n, int mquan
break;
idx = vc1_simple_progressive_4x4_zz[i++];
block[idx + off] = value * scale;
if(!v->pquantizer)
block[idx + off] += (block[idx + off] < 0) ? -mquant : mquant;
}
if(!(subblkpat & (1 << (3 - j))))
vc1_inv_trans(block + off, 4, 4);
@ -2343,6 +2348,8 @@ static int vc1_decode_p_block(VC1Context *v, DCTELEM block[64], int n, int mquan
break;
idx = vc1_simple_progressive_8x4_zz[i++];
block[idx + off] = value * scale;
if(!v->pquantizer)
block[idx + off] += (block[idx + off] < 0) ? -mquant : mquant;
}
if(!(subblkpat & (1 << (1 - j))))
vc1_inv_trans(block + off, 8, 4);
@ -2360,6 +2367,8 @@ static int vc1_decode_p_block(VC1Context *v, DCTELEM block[64], int n, int mquan
break;
idx = vc1_simple_progressive_4x8_zz[i++];
block[idx + off] = value * scale;
if(!v->pquantizer)
block[idx + off] += (block[idx + off] < 0) ? -mquant : mquant;
}
if(!(subblkpat & (1 << (1 - j))))
vc1_inv_trans(block + off, 4, 8);