/**
* generic linear sample quantize and dither routine
* (copied from mpg231, mad.c)
* @author Rob Leslie
*/
static inline qint32 audio_linear_dither(unsigned int bits,
mad_fixed_t sample, Kwave::audio_dither *dither)
{
unsigned int scalebits;
mad_fixed_t output, mask, random;
enum {
MIN = -MAD_F_ONE,
MAX = MAD_F_ONE - 1
};
/* noise shape */
sample += dither->error[0] - dither->error[1] + dither->error[2];
dither->error[2] = dither->error[1];
dither->error[1] = dither->error[0] / 2;
/* bias */
output = sample + mad_fixed_t(1L << (MAD_F_FRACBITS + 1 - bits - 1));
scalebits = MAD_F_FRACBITS + 1 - bits;
mask = mad_fixed_t(1L << scalebits) - 1;
/* dither */
random = static_cast<mad_fixed_t>(prng(dither->random));
output += (random & mask) - (dither->random & mask);
dither->random = random;
/* clip */
if (output > MAX) {
output = MAX;
if (sample > MAX) sample = MAX;
} else if (output < MIN) {
output = MIN;
if (sample < MIN) sample = MIN;
}
/* quantize */
output &= ~mask;
/* error feedback */
dither->error[0] = sample - output;
/* scale */
return output >> scalebits;
}
/*
* NAME: synth->half()
* DESCRIPTION: perform half frequency PCM synthesis
*/
static
void synth_half(struct mad_synth *synth, struct mad_frame /*const*/ *frame,
unsigned int nch, unsigned int ns)
{
unsigned int phase, ch, s, sb, pe, po;
short int *pcm1, *pcm2;
mad_fixed_t (*filter)[2][2][16][8];
mad_fixed_t (*sbsample)[36][32];
register mad_fixed_t (*fe)[8], (*fx)[8], (*fo)[8];
register mad_fixed_t const (*Dptr)[32], *ptr ;
register mad_fixed64hi_t hi;
register mad_fixed64lo_t lo;
mad_fixed_t raw_sample;
static short int short_sample_buff[16];
phase = synth->phase;
for (s = 0; s < ns; ++s)
{
memset (short_sample_buff, 0x00, sizeof(short_sample_buff));
for (ch = 0; ch < nch; ++ch)
{
sbsample = &frame->sbsample[ch];
filter = &synth->filter[ch];
pcm1 = short_sample_buff;
dct32((*sbsample)[s], phase >> 1,
(*filter)[0][phase & 1], (*filter)[1][phase & 1]);
pe = phase & ~1;
po = ((phase - 1) & 0xf) | 1;
/* calculate 16 samples */
fe = &(*filter)[0][ phase & 1][0];
fx = &(*filter)[0][~phase & 1][0];
fo = &(*filter)[1][~phase & 1][0];
Dptr = &D[0];
ptr = *Dptr + po;
ML0(hi, lo, (*fx)[0], ptr[ 0]);
MLA(hi, lo, (*fx)[1], ptr[14]);
MLA(hi, lo, (*fx)[2], ptr[12]);
MLA(hi, lo, (*fx)[3], ptr[10]);
MLA(hi, lo, (*fx)[4], ptr[ 8]);
MLA(hi, lo, (*fx)[5], ptr[ 6]);
MLA(hi, lo, (*fx)[6], ptr[ 4]);
MLA(hi, lo, (*fx)[7], ptr[ 2]);
MLN(hi, lo);
ptr = *Dptr + pe;
MLA(hi, lo, (*fe)[0], ptr[ 0]);
MLA(hi, lo, (*fe)[1], ptr[14]);
MLA(hi, lo, (*fe)[2], ptr[12]);
MLA(hi, lo, (*fe)[3], ptr[10]);
MLA(hi, lo, (*fe)[4], ptr[ 8]);
MLA(hi, lo, (*fe)[5], ptr[ 6]);
MLA(hi, lo, (*fe)[6], ptr[ 4]);
MLA(hi, lo, (*fe)[7], ptr[ 2]);
raw_sample = SHIFT(MLZ(hi, lo));
raw_sample = scale(raw_sample);
(*pcm1++) += (short int)raw_sample;
pcm2 = pcm1 + 14;
for (sb = 1; sb < 16; ++sb)
{
++fe;
++Dptr;
/* D[32 - sb][i] == -D[sb][31 - i] */
ptr = *Dptr + po;
ML0(hi, lo, (*fo)[0], ptr[ 0]);
MLA(hi, lo, (*fo)[1], ptr[14]);
MLA(hi, lo, (*fo)[2], ptr[12]);
MLA(hi, lo, (*fo)[3], ptr[10]);
MLA(hi, lo, (*fo)[4], ptr[ 8]);
MLA(hi, lo, (*fo)[5], ptr[ 6]);
MLA(hi, lo, (*fo)[6], ptr[ 4]);
MLA(hi, lo, (*fo)[7], ptr[ 2]);
MLN(hi, lo);
ptr = *Dptr + pe;
MLA(hi, lo, (*fe)[7], ptr[ 2]);
MLA(hi, lo, (*fe)[6], ptr[ 4]);
MLA(hi, lo, (*fe)[5], ptr[ 6]);
MLA(hi, lo, (*fe)[4], ptr[ 8]);
MLA(hi, lo, (*fe)[3], ptr[10]);
MLA(hi, lo, (*fe)[2], ptr[12]);
MLA(hi, lo, (*fe)[1], ptr[14]);
MLA(hi, lo, (*fe)[0], ptr[ 0]);
raw_sample = SHIFT(MLZ(hi, lo));
raw_sample = scale(raw_sample);
(*pcm1++) += (short int)raw_sample;
ptr = *Dptr - pe;
ML0(hi, lo, (*fe)[0], ptr[31 - 16]);
MLA(hi, lo, (*fe)[1], ptr[31 - 14]);
MLA(hi, lo, (*fe)[2], ptr[31 - 12]);
MLA(hi, lo, (*fe)[3], ptr[31 - 10]);
MLA(hi, lo, (*fe)[4], ptr[31 - 8]);
MLA(hi, lo, (*fe)[5], ptr[31 - 6]);
MLA(hi, lo, (*fe)[6], ptr[31 - 4]);
MLA(hi, lo, (*fe)[7], ptr[31 - 2]);
ptr = *Dptr - po;
MLA(hi, lo, (*fo)[7], ptr[31 - 2]);
MLA(hi, lo, (*fo)[6], ptr[31 - 4]);
MLA(hi, lo, (*fo)[5], ptr[31 - 6]);
MLA(hi, lo, (*fo)[4], ptr[31 - 8]);
MLA(hi, lo, (*fo)[3], ptr[31 - 10]);
MLA(hi, lo, (*fo)[2], ptr[31 - 12]);
MLA(hi, lo, (*fo)[1], ptr[31 - 14]);
MLA(hi, lo, (*fo)[0], ptr[31 - 16]);
raw_sample = SHIFT(MLZ(hi, lo));
raw_sample = scale(raw_sample);
(*pcm2--) += (short int)raw_sample;
++fo;
}
Dptr++;
ptr = *Dptr + po;
ML0(hi, lo, (*fo)[0], ptr[ 0]);
MLA(hi, lo, (*fo)[1], ptr[14]);
MLA(hi, lo, (*fo)[2], ptr[12]);
MLA(hi, lo, (*fo)[3], ptr[10]);
MLA(hi, lo, (*fo)[4], ptr[ 8]);
MLA(hi, lo, (*fo)[5], ptr[ 6]);
MLA(hi, lo, (*fo)[6], ptr[ 4]);
MLA(hi, lo, (*fo)[7], ptr[ 2]);
raw_sample = SHIFT(-MLZ(hi, lo));
raw_sample = scale(raw_sample);
(*pcm1) += (short int)raw_sample;
} /* Channel For */
/* Block render */
//--render_sample_block(short_sample_buff, 16);
WriteMP3ToBuffer(short_sample_buff,16);
phase = (phase + 1) % 16;
}/* Block For */
}
