private void ReduceBitsPerSample24Other(ConvertParams args, DataSubChunk toDsc)
{
uint mask = 0xffffffff << (24 - args.newQuantizationBitrate);
uint maskError = ~mask;
var gen = new RNGCryptoServiceProvider();
var gng = new GaussianNoiseGenerator();
var randomNumber = new byte[3];
int noiseMagnitude = (int)Math.Pow(2, (24 - args.newQuantizationBitrate)) / 2;
Console.WriteLine("D: maskErr={0:X}", maskError);
int bytesPerFrame = mFsc.numChannels * mFsc.bitsPerSample / 8;
int numFrames = toDsc.data.Length / bytesPerFrame;
int pos = 0;
for (int i = 0; i < numFrames; ++i)
{
for (int ch = 0; ch < mFsc.numChannels; ++ch)
{
double sample = ReadSampleValue24(toDsc, pos);
uint error = (uint)sample & maskError;
sample -= error;
switch (args.ditherType)
{
case ConvertParams.DitherType.Truncate:
break;
case ConvertParams.DitherType.RpdfDither:
gen.GetBytes(randomNumber);
int randDither = (int)((randomNumber[0]) + (randomNumber[1] << 8) + (randomNumber[2] << 16) & ~mask);
sample += randDither;
break;
case ConvertParams.DitherType.GaussianDither:
float noise = gng.NextFloat();
noise *= noiseMagnitude;
sample += (int)noise;
break;
default:
System.Diagnostics.Debug.Assert(false);
break;
}
if (0x7fffff < sample)
{
sample = 0x7fffff;
}
if (sample < -0x800000)
{
sample = -0x800000;
}
WriteSampleValue24(toDsc, pos, (int)sample);
pos += mFsc.bitsPerSample / 8;
}
}
}
private void ReduceBitsPerSample24Other(ConvertParams args, DataSubChunk toDsc)
{
uint mask = 0xffffffff << (24 - args.newQuantizationBitrate);
uint maskError = ~mask;
var gen = new RNGCryptoServiceProvider();
var gng = new GaussianNoiseGenerator();
var randomNumber = new byte[3];
int noiseMagnitude = (int)Math.Pow(2, (24 - args.newQuantizationBitrate))/2;
Console.WriteLine("D: maskErr={0:X}", maskError);
int bytesPerFrame = mFsc.numChannels * mFsc.bitsPerSample / 8;
int numFrames = toDsc.data.Length / bytesPerFrame;
int pos = 0;
for (int i=0; i < numFrames; ++i) {
for (int ch=0; ch < mFsc.numChannels; ++ch) {
double sample = ReadSampleValue24(toDsc, pos);
uint error = (uint)sample & maskError;
sample -= error;
switch (args.ditherType) {
case ConvertParams.DitherType.Truncate:
break;
case ConvertParams.DitherType.RpdfDither:
gen.GetBytes(randomNumber);
int randDither = (int)((randomNumber[0]) + (randomNumber[1] << 8) + (randomNumber[2]<<16) & ~mask);
sample += randDither;
break;
case ConvertParams.DitherType.GaussianDither:
float noise = gng.NextFloat();
noise *= noiseMagnitude;
sample += (int)noise;
break;
default:
System.Diagnostics.Debug.Assert(false);
break;
}
if (0x7fffff < sample) {
sample = 0x7fffff;
}
if (sample < -0x800000) {
sample = -0x800000;
}
WriteSampleValue24(toDsc, pos, (int)sample);
pos += mFsc.bitsPerSample / 8;
}
}
}