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DCA: fix multichannel -> 2 channel downmix.

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Patch by Nick Brereton

Originally committed as revision 24555 to svn://svn.ffmpeg.org/ffmpeg/trunk
oldabi
Nick Brereton 15 years ago committed by Benjamin Larsson
parent 08634e7bda
commit df9844937f
1 changed files with 33 additions and 14 deletions
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  1. 47
      libavcodec/dca.c

47
libavcodec/dca.c
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@ -879,17 +879,19 @@ static void lfe_interpolation_fir(DCAContext *s, int decimation_select,
/* downmixing routines */
#define MIX_REAR1(samples, si1, rs, coef) \
samples[i] += samples[si1] * coef[rs][0]; \
samples[i+256] += samples[si1] * coef[rs][1];
samples[i] += (samples[si1] - add_bias) * coef[rs][0]; \
samples[i+256] += (samples[si1] - add_bias) * coef[rs][1];
#define MIX_REAR2(samples, si1, si2, rs, coef) \
samples[i] += samples[si1] * coef[rs][0] + samples[si2] * coef[rs+1][0]; \
samples[i+256] += samples[si1] * coef[rs][1] + samples[si2] * coef[rs+1][1];
samples[i] += (samples[si1] - add_bias) * coef[rs][0] + (samples[si2] - add_bias) * coef[rs+1][0]; \
samples[i+256] += (samples[si1] - add_bias) * coef[rs][1] + (samples[si2] - add_bias) * coef[rs+1][1];
#define MIX_FRONT3(samples, coef) \
t = samples[i]; \
samples[i] = t * coef[0][0] + samples[i+256] * coef[1][0] + samples[i+512] * coef[2][0]; \
samples[i+256] = t * coef[0][1] + samples[i+256] * coef[1][1] + samples[i+512] * coef[2][1];
t = samples[i+c] - add_bias; \
u = samples[i+l] - add_bias; \
v = samples[i+r] - add_bias; \
samples[i] = t * coef[0][0] + u * coef[1][0] + v * coef[2][0] + add_bias; \
samples[i+256] = t * coef[0][1] + u * coef[1][1] + v * coef[2][1] + add_bias;
#define DOWNMIX_TO_STEREO(op1, op2) \
for (i = 0; i < 256; i++){ \
@ -898,10 +900,12 @@ static void lfe_interpolation_fir(DCAContext *s, int decimation_select,
}
static void dca_downmix(float *samples, int srcfmt,
int downmix_coef[DCA_PRIM_CHANNELS_MAX][2])
int downmix_coef[DCA_PRIM_CHANNELS_MAX][2],
const int8_t *channel_mapping, float add_bias)
{
int c,l,r,sl,sr,s;
int i;
float t;
float t, u, v;
float coef[DCA_PRIM_CHANNELS_MAX][2];
for (i=0; i<DCA_PRIM_CHANNELS_MAX; i++) {
@ -920,21 +924,36 @@ static void dca_downmix(float *samples, int srcfmt,
case DCA_STEREO:
break;
case DCA_3F:
c = channel_mapping[0] * 256;
l = channel_mapping[1] * 256;
r = channel_mapping[2] * 256;
DOWNMIX_TO_STEREO(MIX_FRONT3(samples, coef),);
break;
case DCA_2F1R:
DOWNMIX_TO_STEREO(MIX_REAR1(samples, i + 512, 2, coef),);
s = channel_mapping[2] * 256;
DOWNMIX_TO_STEREO(MIX_REAR1(samples, i + s, 2, coef),);
break;
case DCA_3F1R:
c = channel_mapping[0] * 256;
l = channel_mapping[1] * 256;
r = channel_mapping[2] * 256;
s = channel_mapping[3] * 256;
DOWNMIX_TO_STEREO(MIX_FRONT3(samples, coef),
MIX_REAR1(samples, i + 768, 3, coef));
MIX_REAR1(samples, i + s, 3, coef));
break;
case DCA_2F2R:
DOWNMIX_TO_STEREO(MIX_REAR2(samples, i + 512, i + 768, 2, coef),);
sl = channel_mapping[2] * 256;
sr = channel_mapping[3] * 256;
DOWNMIX_TO_STEREO(MIX_REAR2(samples, i + sl, i + sr, 2, coef),);
break;
case DCA_3F2R:
c = channel_mapping[0] * 256;
l = channel_mapping[1] * 256;
r = channel_mapping[2] * 256;
sl = channel_mapping[3] * 256;
sr = channel_mapping[4] * 256;
DOWNMIX_TO_STEREO(MIX_FRONT3(samples, coef),
MIX_REAR2(samples, i + 768, i + 1024, 3, coef));
MIX_REAR2(samples, i + sl, i + sr, 3, coef));
break;
}
}
@ -1117,7 +1136,7 @@ static int dca_filter_channels(DCAContext * s, int block_index)
/* Down mixing */
if (s->avctx->request_channels == 2 && s->prim_channels > 2) {
dca_downmix(s->samples, s->amode, s->downmix_coef);
dca_downmix(s->samples, s->amode, s->downmix_coef, s->channel_order_tab, s->add_bias);
}
/* Generate LFE samples for this subsubframe FIXME!!! */

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