size_t EffectBassTreble::InstanceProcess(EffectBassTrebleState & data,
float **inBlock,
float **outBlock,
size_t blockLen)
{
float *ibuf = inBlock[0];
float *obuf = outBlock[0];
// Set value to ensure correct rounding
double oldBass = DB_TO_LINEAR(mBass);
double oldTreble = DB_TO_LINEAR(mTreble);
data.gain = DB_TO_LINEAR(mGain);
// Compute coefficents of the low shelf biquand IIR filter
if (data.bass != oldBass)
Coefficents(data.hzBass, data.slope, mBass, data.samplerate, kBass,
data.a0Bass, data.a1Bass, data.a2Bass,
data.b0Bass, data.b1Bass, data.b2Bass);
// Compute coefficents of the high shelf biquand IIR filter
if (data.treble != oldTreble)
Coefficents(data.hzTreble, data.slope, mTreble, data.samplerate, kTreble,
data.a0Treble, data.a1Treble, data.a2Treble,
data.b0Treble, data.b1Treble, data.b2Treble);
for (decltype(blockLen) i = 0; i < blockLen; i++) {
obuf[i] = DoFilter(data, ibuf[i]) * data.gain;
}
return blockLen;
}
bool EffectBassTreble::NewTrackPass1()
{
const float slope = 0.4f; // same slope for both filters
const double hzBass = 250.0f;
const double hzTreble = 4000.0f;
//(re)initialise filter parameters
xn1Bass=xn2Bass=yn1Bass=yn2Bass=0;
xn1Treble=xn2Treble=yn1Treble=yn2Treble=0;
// Compute coefficents of the low shelf biquand IIR filter
Coefficents(hzBass, slope, dB_bass, bassType,
a0Bass, a1Bass, a2Bass,
b0Bass, b1Bass, b2Bass);
// Compute coefficents of the high shelf biquand IIR filter
Coefficents(hzTreble, slope, dB_treble, trebleType,
a0Treble, a1Treble, a2Treble,
b0Treble, b1Treble, b2Treble);
return true;
}