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flac: Implement proper support for 7 channel FLACs

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* Allocate buffer for additional channel
 * Proper downmixing

Change-Id: I4190358a93bb328585952affcd42db05b05c19a5
This commit is contained in:
Solomon Peachy 2024-10-14 12:23:53 -04:00
parent 3aef933348
commit 29f28ad8e6
2 changed files with 22 additions and 2 deletions
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20
lib/rbcodec/codecs/libffmpegFLAC/decoder.c
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@ -531,7 +531,7 @@ static int decode_frame(FLACContext *s,
static int flac_downmix(FLACContext *s) ICODE_ATTR_FLAC;
static int flac_downmix(FLACContext *s)
{
int32_t *FL, *FR, *FC, *SB, *RL, *RR;
int32_t *FL, *FR, *FC, *SB, *RL, *RR, *RC;
int32_t *outL = s->decoded[0];
int32_t *outR = s->decoded[1];
int i, scale=FLAC_OUTPUT_DEPTH-s->bps;
@ -600,6 +600,24 @@ static int flac_downmix(FLACContext *s)
FL++; FR++; SB++; FC++; RL++; RR++;
}
break;
case 7: /* 6.1 channel order: FL FR FC SUB RL RR RC */
FL = s->decoded[0];
FR = s->decoded[1];
FC = s->decoded[2];
SB = s->decoded[3];
RL = s->decoded[4];
RR = s->decoded[5];
RC = s->decoded[6];
/* LF = 0.28 LF + 0.14 SUB + 0.14 FC + 0.28 RL + 0.00 RR + 0.14 CR
LR = 0.28 LR + 0.14 SUB + 0.14 FC + 0.00 RL + 0.28 RR + 0.14 CR */
for (i=0; i<s->blocksize; ++i) {
int32_t a = *(FL)*2 + *(SB) + *(FC) + *(RL)*2 + *(RC);
int32_t b = *(FR)*2 + *(SB) + *(FC) + *(RR)*2 + *(RC);
*outL++ = ((a + (a<<4))>>6) << scale; /* 9>>6 ~= 1/7 */
*outR++ = ((b + (b<<4))>>6) << scale; /* 9>>6 ~= 1/7 */
FL++; FR++; SB++; FC++; RL++; RR++; RC++;
}
break;
default: /* 1.0 and 2.0 do not need downmix, other formats unknown. */
return -501;
break;