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replaygain_synthesis.c  view on Meta::CPAN

	/* Parity calculation is done via table lookup, this is also available
	 * on CPUs without parity, can be implemented in C and avoid unpredictable
	 * jumps and slow rotate through the carry flag operations.
	 */
	t3   = t1 = r1_;    t4   = t2 = r2_;
	t1  &= 0xF5;        t2 >>= 25;
	t1   = parity_[t1]; t2  &= 0x63;
	t1 <<= 31;          t2   = parity_[t2];

	return (r1_ = (t3 >> 1) | t1 ) ^ (r2_ = (t4 + t4) | t2 );
}

/* gives a equal distributed random number */
/* between -2^31*mult and +2^31*mult */
static double random_equi_(double mult)
{
	return mult * (int) random_int_();
}

/* gives a triangular distributed random number */
/* between -2^32*mult and +2^32*mult */
static double random_triangular_(double mult)
{
	return mult * ( (double) (int) random_int_() + (double) (int) random_int_() );
}


static const float  F44_0 [16 + 32] = {
	(float)0, (float)0, (float)0, (float)0, (float)0, (float)0, (float)0, (float)0,
	(float)0, (float)0, (float)0, (float)0, (float)0, (float)0, (float)0, (float)0,

	(float)0, (float)0, (float)0, (float)0, (float)0, (float)0, (float)0, (float)0,
	(float)0, (float)0, (float)0, (float)0, (float)0, (float)0, (float)0, (float)0,

	(float)0, (float)0, (float)0, (float)0, (float)0, (float)0, (float)0, (float)0,
	(float)0, (float)0, (float)0, (float)0, (float)0, (float)0, (float)0, (float)0
};


static const float  F44_1 [16 + 32] = {  /* SNR(w) = 4.843163 dB, SNR = -3.192134 dB */
	(float) 0.85018292704024355931, (float) 0.29089597350995344721, (float)-0.05021866022121039450, (float)-0.23545456294599161833,
	(float)-0.58362726442227032096, (float)-0.67038978965193036429, (float)-0.38566861572833459221, (float)-0.15218663390367969967,
	(float)-0.02577543084864530676, (float) 0.14119295297688728127, (float) 0.22398848581628781612, (float) 0.15401727203382084116,
	(float) 0.05216161232906000929, (float)-0.00282237820999675451, (float)-0.03042794608323867363, (float)-0.03109780942998826024,

	(float) 0.85018292704024355931, (float) 0.29089597350995344721, (float)-0.05021866022121039450, (float)-0.23545456294599161833,
	(float)-0.58362726442227032096, (float)-0.67038978965193036429, (float)-0.38566861572833459221, (float)-0.15218663390367969967,
	(float)-0.02577543084864530676, (float) 0.14119295297688728127, (float) 0.22398848581628781612, (float) 0.15401727203382084116,
	(float) 0.05216161232906000929, (float)-0.00282237820999675451, (float)-0.03042794608323867363, (float)-0.03109780942998826024,

	(float) 0.85018292704024355931, (float) 0.29089597350995344721, (float)-0.05021866022121039450, (float)-0.23545456294599161833,
	(float)-0.58362726442227032096, (float)-0.67038978965193036429, (float)-0.38566861572833459221, (float)-0.15218663390367969967,
	(float)-0.02577543084864530676, (float) 0.14119295297688728127, (float) 0.22398848581628781612, (float) 0.15401727203382084116,
	(float) 0.05216161232906000929, (float)-0.00282237820999675451, (float)-0.03042794608323867363, (float)-0.03109780942998826024,
};


static const float  F44_2 [16 + 32] = {  /* SNR(w) = 10.060213 dB, SNR = -12.766730 dB */
	(float) 1.78827593892108555290, (float) 0.95508210637394326553, (float)-0.18447626783899924429, (float)-0.44198126506275016437,
	(float)-0.88404052492547413497, (float)-1.42218907262407452967, (float)-1.02037566838362314995, (float)-0.34861755756425577264,
	(float)-0.11490230170431934434, (float) 0.12498899339968611803, (float) 0.38065885268563131927, (float) 0.31883491321310506562,
	(float) 0.10486838686563442765, (float)-0.03105361685110374845, (float)-0.06450524884075370758, (float)-0.02939198261121969816,

	(float) 1.78827593892108555290, (float) 0.95508210637394326553, (float)-0.18447626783899924429, (float)-0.44198126506275016437,
	(float)-0.88404052492547413497, (float)-1.42218907262407452967, (float)-1.02037566838362314995, (float)-0.34861755756425577264,
	(float)-0.11490230170431934434, (float) 0.12498899339968611803, (float) 0.38065885268563131927, (float) 0.31883491321310506562,
	(float) 0.10486838686563442765, (float)-0.03105361685110374845, (float)-0.06450524884075370758, (float)-0.02939198261121969816,

	(float) 1.78827593892108555290, (float) 0.95508210637394326553, (float)-0.18447626783899924429, (float)-0.44198126506275016437,
	(float)-0.88404052492547413497, (float)-1.42218907262407452967, (float)-1.02037566838362314995, (float)-0.34861755756425577264,
	(float)-0.11490230170431934434, (float) 0.12498899339968611803, (float) 0.38065885268563131927, (float) 0.31883491321310506562,
	(float) 0.10486838686563442765, (float)-0.03105361685110374845, (float)-0.06450524884075370758, (float)-0.02939198261121969816,
};


static const float  F44_3 [16 + 32] = {  /* SNR(w) = 15.382598 dB, SNR = -29.402334 dB */
	(float) 2.89072132015058161445, (float) 2.68932810943698754106, (float) 0.21083359339410251227, (float)-0.98385073324997617515,
	(float)-1.11047823227097316719, (float)-2.18954076314139673147, (float)-2.36498032881953056225, (float)-0.95484132880101140785,
	(float)-0.23924057925542965158, (float)-0.13865235703915925642, (float) 0.43587843191057992846, (float) 0.65903257226026665927,
	(float) 0.24361815372443152787, (float)-0.00235974960154720097, (float) 0.01844166574603346289, (float) 0.01722945988740875099,

	(float) 2.89072132015058161445, (float) 2.68932810943698754106, (float) 0.21083359339410251227, (float)-0.98385073324997617515,
	(float)-1.11047823227097316719, (float)-2.18954076314139673147, (float)-2.36498032881953056225, (float)-0.95484132880101140785,
	(float)-0.23924057925542965158, (float)-0.13865235703915925642, (float) 0.43587843191057992846, (float) 0.65903257226026665927,
	(float) 0.24361815372443152787, (float)-0.00235974960154720097, (float) 0.01844166574603346289, (float) 0.01722945988740875099,

	(float) 2.89072132015058161445, (float) 2.68932810943698754106, (float) 0.21083359339410251227, (float)-0.98385073324997617515,
	(float)-1.11047823227097316719, (float)-2.18954076314139673147, (float)-2.36498032881953056225, (float)-0.95484132880101140785,
	(float)-0.23924057925542965158, (float)-0.13865235703915925642, (float) 0.43587843191057992846, (float) 0.65903257226026665927,
	(float) 0.24361815372443152787, (float)-0.00235974960154720097, (float) 0.01844166574603346289, (float) 0.01722945988740875099
};


static double scalar16_(const float* x, const float* y)
{
	return
		x[ 0]*y[ 0] + x[ 1]*y[ 1] + x[ 2]*y[ 2] + x[ 3]*y[ 3] +
		x[ 4]*y[ 4] + x[ 5]*y[ 5] + x[ 6]*y[ 6] + x[ 7]*y[ 7] +
		x[ 8]*y[ 8] + x[ 9]*y[ 9] + x[10]*y[10] + x[11]*y[11] +
		x[12]*y[12] + x[13]*y[13] + x[14]*y[14] + x[15]*y[15];
}


void FLAC__replaygain_synthesis__init_dither_context(DitherContext *d, int bits, int shapingtype)
{
	static unsigned char default_dither [] = { 92, 92, 88, 84, 81, 78, 74, 67,  0,  0 };
	static const float*               F [] = { F44_0, F44_1, F44_2, F44_3 };

	int index;

	if (shapingtype < 0) shapingtype = 0;
	if (shapingtype > 3) shapingtype = 3;
	d->ShapingType = (NoiseShaping)shapingtype;
	index = bits - 11 - shapingtype;
	if (index < 0) index = 0;
	if (index > 9) index = 9;

	memset ( d->ErrorHistory , 0, sizeof (d->ErrorHistory ) );
	memset ( d->DitherHistory, 0, sizeof (d->DitherHistory) );

	d->FilterCoeff = F [shapingtype];
	d->Mask   = ((FLAC__uint64)-1) << (32 - bits);
	d->Add    = 0.5     * ((1L << (32 - bits)) - 1);
	d->Dither = 0.01f*default_dither[index] / (((FLAC__int64)1) << bits);
	d->LastHistoryIndex = 0;
}

/*
 * the following is based on parts of wavegain.c
 */

static FLAC__INLINE FLAC__int64 dither_output_(DitherContext *d, FLAC__bool do_dithering, int shapingtype, int i, double Sum, int k)
{
	double doubletmp, Sum2;
	FLAC__int64 val;

#define ROUND64(x)   ( doubletmp = (x) + d->Add + (FLAC__int64)0x001FFFFD80000000L, *(FLAC__int64*)(&doubletmp) - (FLAC__int64)0x433FFFFD80000000L )

	if(do_dithering) {
		if(shapingtype == 0) {
			double  tmp = random_equi_(d->Dither);
			Sum2 = tmp - d->LastRandomNumber [k];
			d->LastRandomNumber [k] = (int)tmp;
			Sum2 = Sum += Sum2;
			val = ROUND64(Sum2) & d->Mask;
		}
		else {
			Sum2 = random_triangular_(d->Dither) - scalar16_(d->DitherHistory[k], d->FilterCoeff + i);
			Sum += d->DitherHistory [k] [(-1-i)&15] = (float)Sum2;
			Sum2 = Sum + scalar16_(d->ErrorHistory [k], d->FilterCoeff + i);