public virtual void initImdct(FFT mdctCtx)
{
SineWin.initFfSineWindows();
// Initialize the MDCT transform
mdctCtx.mdctInit(8, true, -1.0);
}
public virtual void ipqf(FFT dctCtx, IPQFChannelContext hist, float[] @in, float[] @out)
{
float[] idctIn = new float[ATRAC3P_SUBBANDS];
float[] idctOut = new float[ATRAC3P_SUBBANDS];
Arrays.Fill(@out, 0, ATRAC3P_FRAME_SAMPLES, 0f);
for (int s = 0; s < ATRAC3P_SUBBAND_SAMPLES; s++)
{
// pack up one sample from each subband
for (int sb = 0; sb < ATRAC3P_SUBBANDS; sb++)
{
idctIn[sb] = @in[sb * ATRAC3P_SUBBAND_SAMPLES + s];
}
// Calculate the sine and cosine part of the PQF using IDCT-IV
dctCtx.imdctHalf(idctOut, 0, idctIn, 0);
// append the result to the history
for (int i = 0; i < 8; i++)
{
hist.buf1[hist.pos][i] = idctOut[i + 8];
hist.buf2[hist.pos][i] = idctOut[7 - i];
}
int posNow = hist.pos;
int posNext = mod23_lut[posNow + 2]; // posNext = (posNow + 1) % 23
for (int t = 0; t < ATRAC3P_PQF_FIR_LEN; t++)
{
for (int i = 0; i < 8; i++)
{
@out[s * 16 + i + 0] += hist.buf1[posNow][i] * ipqf_coeffs1[t][i] + hist.buf2[posNext][i] * ipqf_coeffs2[t][i];
@out[s * 16 + i + 8] += hist.buf1[posNow][7 - i] * ipqf_coeffs1[t][i + 8] + hist.buf2[posNext][7 - i] * ipqf_coeffs2[t][i + 8];
}
posNow = mod23_lut[posNext + 2]; // posNow = (posNow + 2) % 23;
posNext = mod23_lut[posNow + 2]; // posNext = (posNext + 2) % 23;
}
hist.pos = mod23_lut[hist.pos]; // hist.pos = (hist.pos - 1) % 23;
}
}
public virtual void imdct(FFT mdctCtx, float[] @in, int inOffset, float[] @out, int outOffset, int windId, int sb)
{
if ((sb & 1) != 0)
{
for (int i = 0; i < ATRAC3P_SUBBAND_SAMPLES / 2; i++)
{
float tmp = @in[inOffset + i];
@in[inOffset + i] = @in[inOffset + ATRAC3P_SUBBAND_SAMPLES - 1 - i];
@in[inOffset + ATRAC3P_SUBBAND_SAMPLES - 1 - i] = tmp;
}
}
mdctCtx.imdctCalc(@out, outOffset, @in, inOffset);
/* Perform windowing on the output.
* ATRAC3+ uses two different MDCT windows:
* - The first one is just the plain sine window of size 256
* - The 2nd one is the plain sine window of size 128
* wrapped into zero (at the start) and one (at the end) regions.
* Both regions are 32 samples long. */
if ((windId & 2) != 0)
{ // 1st half: steep window
Arrays.Fill(@out, outOffset, outOffset + 32, 0f);
vectorFmul(@out, outOffset + 32, @out, outOffset + 32, ff_sine_64, 0, 64);
}
else
{ // 1st halt: simple sine window
vectorFmul(@out, outOffset, @out, outOffset, ff_sine_128, 0, ATRAC3P_MDCT_SIZE / 2);
}
if ((windId & 1) != 0)
{ // 2nd half: steep window
vectorFmulReverse(@out, outOffset + 160, @out, outOffset + 160, ff_sine_64, 0, 64);
Arrays.Fill(@out, outOffset + 224, outOffset + 224 + 32, 0f);
}
else
{ // 2nd half: simple sine window
vectorFmulReverse(@out, outOffset + 128, @out, outOffset + 128, ff_sine_128, 0, ATRAC3P_MDCT_SIZE / 2);
}
}
