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simplify coefficient decoding 

Originally committed as revision 9884 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2007-08-04 00:12:23 +00:00
parent 285bf28c67
commit d63f6fea50
1 changed files with 15 additions and 16 deletions
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31
libavcodec/ac3dec.c
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@ -495,13 +495,11 @@ static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_gro
case 0: case 0:
if (!dithflag) { if (!dithflag) {
coeffs[i] = 0; coeffs[i] = 0;
continue;
} }
else { else {
coeffs[i] = (av_random(&ctx->dith_state) & 0xFFFF) * scale_factors[exps[i]]; coeffs[i] = (av_random(&ctx->dith_state) & 0xFFFF) * LEVEL_MINUS_3DB;
coeffs[i] *= LEVEL_MINUS_3DB;
continue;
} }
break;
case 1: case 1:
if (m->l3ptr > 2) { if (m->l3ptr > 2) {
@ -511,8 +509,8 @@ static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_gro
m->l3_quantizers[2] = l3_quantizers_3[gcode]; m->l3_quantizers[2] = l3_quantizers_3[gcode];
m->l3ptr = 0; m->l3ptr = 0;
} }
coeffs[i] = m->l3_quantizers[m->l3ptr++] * scale_factors[exps[i]]; coeffs[i] = m->l3_quantizers[m->l3ptr++];
continue; break;
case 2: case 2:
if (m->l5ptr > 2) { if (m->l5ptr > 2) {
@ -522,12 +520,12 @@ static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_gro
m->l5_quantizers[2] = l5_quantizers_3[gcode]; m->l5_quantizers[2] = l5_quantizers_3[gcode];
m->l5ptr = 0; m->l5ptr = 0;
} }
coeffs[i] = m->l5_quantizers[m->l5ptr++] * scale_factors[exps[i]]; coeffs[i] = m->l5_quantizers[m->l5ptr++];
continue; break;
case 3: case 3:
coeffs[i] = l7_quantizers[get_bits(gb, 3)] * scale_factors[exps[i]]; coeffs[i] = l7_quantizers[get_bits(gb, 3)];
continue; break;
case 4: case 4:
if (m->l11ptr > 1) { if (m->l11ptr > 1) {
@ -536,17 +534,18 @@ static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_gro
m->l11_quantizers[1] = l11_quantizers_2[gcode]; m->l11_quantizers[1] = l11_quantizers_2[gcode];
m->l11ptr = 0; m->l11ptr = 0;
} }
coeffs[i] = m->l11_quantizers[m->l11ptr++] * scale_factors[exps[i]]; coeffs[i] = m->l11_quantizers[m->l11ptr++];
continue; break;
case 5: case 5:
coeffs[i] = l15_quantizers[get_bits(gb, 4)] * scale_factors[exps[i]]; coeffs[i] = l15_quantizers[get_bits(gb, 4)];
continue; break;
default: default:
coeffs[i] = (get_sbits(gb, qntztab[tbap]) << (16 - qntztab[tbap])) * scale_factors[exps[i]]; coeffs[i] = get_sbits(gb, qntztab[tbap]) << (16 - qntztab[tbap]);
continue; break;
} }
coeffs[i] *= scale_factors[exps[i]];
} }
return 0; return 0;