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use downmixing coefficients in dca decoder. 

reference:
Subject: [Ffmpeg-devel] [PATCH] DTS multichannel
Date: Wed, 25 Apr 2007 16:25:18 -0400

Originally committed as revision 8875 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2007-05-02 20:33:32 +00:00
parent cc82662662
commit c31a76e4ef
2 changed files with 47 additions and 19 deletions
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53
libavcodec/dca.c
View File

@ -522,11 +522,19 @@ static int dca_subframe_header(DCAContext * s)
}
/* Stereo downmix coefficients */
if (s->prim_channels > 2 && s->downmix) {
if (s->prim_channels > 2) {
if(s->downmix) {
for (j = 0; j < s->prim_channels; j++) {
s->downmix_coef[j][0] = get_bits(&s->gb, 7);
s->downmix_coef[j][1] = get_bits(&s->gb, 7);
}
} else {
int am = s->amode & DCA_CHANNEL_MASK;
for (j = 0; j < s->prim_channels; j++) {
s->downmix_coef[j][0] = dca_default_coeffs[am][j][0];
s->downmix_coef[j][1] = dca_default_coeffs[am][j][1];
}
}
}
/* Dynamic range coefficient */
@ -750,18 +758,18 @@ static void lfe_interpolation_fir(int decimation_select,
}
/* downmixing routines */
#define MIX_REAR1(samples, si1) \
samples[i] += samples[si1]; \
samples[i+256] += samples[si1];
#define MIX_REAR1(samples, si1, rs, coef) \
samples[i] += samples[si1] * coef[rs][0]; \
samples[i+256] += samples[si1] * coef[rs][1];
#define MIX_REAR2(samples, si1, si2) \
samples[i] += samples[si1]; \
samples[i+256] += samples[si2];
#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];
#define MIX_FRONT3(samples) \
#define MIX_FRONT3(samples, coef) \
t = samples[i]; \
samples[i] += samples[i+256]; \
samples[i+256] = samples[i+512] + t;
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];
#define DOWNMIX_TO_STEREO(op1, op2) \
for(i = 0; i < 256; i++){ \
@ -769,10 +777,17 @@ static void lfe_interpolation_fir(int decimation_select,
op2 \
}
static void dca_downmix(float *samples, int srcfmt)
static void dca_downmix(float *samples, int srcfmt,
int downmix_coef[DCA_PRIM_CHANNELS_MAX][2])
{
int i;
float t;
float coef[DCA_PRIM_CHANNELS_MAX][2];
for(i=0; i<DCA_PRIM_CHANNELS_MAX; i++) {
coef[i][0] = dca_downmix_coeffs[downmix_coef[i][0]];
coef[i][1] = dca_downmix_coeffs[downmix_coef[i][1]];
}
switch (srcfmt) {
case DCA_MONO:
@ -785,21 +800,21 @@ static void dca_downmix(float *samples, int srcfmt)
case DCA_STEREO:
break;
case DCA_3F:
DOWNMIX_TO_STEREO(MIX_FRONT3(samples),);
DOWNMIX_TO_STEREO(MIX_FRONT3(samples, coef),);
break;
case DCA_2F1R:
DOWNMIX_TO_STEREO(MIX_REAR1(samples, i + 512),);
DOWNMIX_TO_STEREO(MIX_REAR1(samples, i + 512, 2, coef),);
break;
case DCA_3F1R:
DOWNMIX_TO_STEREO(MIX_FRONT3(samples),
MIX_REAR1(samples, i + 768));
DOWNMIX_TO_STEREO(MIX_FRONT3(samples, coef),
MIX_REAR1(samples, i + 768, 3, coef));
break;
case DCA_2F2R:
DOWNMIX_TO_STEREO(MIX_REAR2(samples, i + 512, i + 768),);
DOWNMIX_TO_STEREO(MIX_REAR2(samples, i + 512, i + 768, 2, coef),);
break;
case DCA_3F2R:
DOWNMIX_TO_STEREO(MIX_FRONT3(samples),
MIX_REAR2(samples, i + 768, i + 1024));
DOWNMIX_TO_STEREO(MIX_FRONT3(samples, coef),
MIX_REAR2(samples, i + 768, i + 1024, 3, coef));
break;
}
}
@ -980,7 +995,7 @@ static int dca_subsubframe(DCAContext * s)
/* Down mixing */
if (s->prim_channels > dca_channels[s->output & DCA_CHANNEL_MASK]) {
dca_downmix(s->samples, s->amode);
dca_downmix(s->samples, s->amode, s->downmix_coef);
}
/* Generate LFE samples for this subsubframe FIXME!!! */

13
libavcodec/dcadata.h
View File

@ -8361,6 +8361,19 @@ static const float dca_downmix_coeffs[65] = {
0.001412537544623, 0.001000000000000, 0.000501187233627, 0.000251188643151, 0.000000000000000,
};
static const uint8_t dca_default_coeffs[16][5][2] = {
{ { 13, 13 }, },
{ { 0, 64 }, { 64, 0 }, },
{ { 0, 64 }, { 64, 0 }, },
{ { 0, 64 }, { 64, 0 }, },
{ { 0, 64 }, { 64, 0 }, },
{ { 6, 6 }, { 0, 25 }, { 25, 0 }, },
{ { 0, 25 }, { 25, 0 }, { 13, 13 }, },
{ { 6, 6 }, { 0, 25 }, { 25, 0 }, { 13, 13 }, },
{ { 0, 25 }, { 25, 0 }, { 0, 13 }, { 13, 0 }, },
{ { 6, 6 }, { 0, 25 }, { 25, 0 }, { 0, 13 }, { 13, 0 }, },
};
/* downmix coeffs
TABLE 9