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Fix stereo for N=2

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This commit is contained in:
Jean-Marc Valin 2010-09-14 10:30:32 -04:00
parent 79b4533846
commit 5f3ad5f985
1 changed files with 24 additions and 9 deletions
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33
libcelt/bands.c
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@ -703,6 +703,14 @@ static void quant_band(int encode, const CELTMode *m, int i, celt_norm *X, celt_
delta = (N-1)*(log2_frac(iside,BITRES+2)-log2_frac(imid,BITRES+2))>>2;
}
#ifdef FIXED_POINT
mid = imid;
side = iside;
#else
mid = (1.f/32768)*imid;
side = (1.f/32768)*iside;
#endif
/* This is a special case for N=2 that only works for stereo and takes
advantage of the fact that mid and side are orthogonal to encode
the side with just one bit. */
@ -737,20 +745,26 @@ static void quant_band(int encode, const CELTMode *m, int i, celt_norm *X, celt_
quant_band(encode, m, i, x2, NULL, N, mbits, spread, B, tf_change, lowband, resynth, ec, remaining_bits, LM, lowband_out, NULL, level+1, seed, gain, lowband_scratch);
y2[0] = -sign*x2[1];
y2[1] = sign*x2[0];
if (resynth)
{
celt_norm tmp;
X[0] = MULT16_16_Q15(mid, X[0]);
X[1] = MULT16_16_Q15(mid, X[1]);
Y[0] = MULT16_16_Q15(side, Y[0]);
Y[1] = MULT16_16_Q15(side, Y[1]);
tmp = X[0];
X[0] = SUB16(tmp,Y[0]);
Y[0] = ADD16(tmp,Y[0]);
tmp = X[1];
X[1] = SUB16(tmp,Y[1]);
Y[1] = ADD16(tmp,Y[1]);
}
} else {
/* "Normal" split code */
celt_norm *next_lowband2=NULL;
celt_norm *next_lowband_out1=NULL;
int next_level=0;
#ifdef FIXED_POINT
mid = imid;
side = iside;
#else
mid = (1.f/32768)*imid;
side = (1.f/32768)*iside;
#endif
/* Give more bits to low-energy MDCTs than they would otherwise deserve */
if (B>1 && !stereo)
delta >>= 1;
@ -808,7 +822,8 @@ static void quant_band(int encode, const CELTMode *m, int i, celt_norm *X, celt_
{
if (stereo)
{
stereo_merge(X, Y, mid, side, N);
if (N!=2)
stereo_merge(X, Y, mid, side, N);
} else if (level == 0)
{
int k;