/// <summary> Initializes the audio system with given settings </summary>
/// <param name="sampleRate"> Sample rate (default is 44.1kHz) </param>
/// <param name="channels"> Number of channels (default is 1) </param>
/// <param name="blocks"> Number of blocks in buffer (default is 8) </param>
/// <param name="blockSamples"> Number of samples per block (default is 512) </param>
public void CreateAudio(uint sampleRate = 44100, uint channels = 1, uint blocks = 8, uint blockSamples = 512)
{
Active = false;
this.sampleRate = sampleRate;
this.channels = channels;
blockCount = blocks;
this.blockSamples = blockSamples;
blockFree = blockCount;
blockCurrent = 0;
blockMemory = null;
waveHeaders = null;
WaveFormatEx waveFormat = new WaveFormatEx {
FormatTag = Windows.WaveFormatPcm,
SamplesPerSec = (int)sampleRate,
BitsPerSample = sizeof(short) * 8,
Channels = (short)channels,
};
waveFormat.BlockAlign = (short)((waveFormat.BitsPerSample / 8) * waveFormat.Channels);
waveFormat.AvgBytesPerSec = waveFormat.SamplesPerSec * waveFormat.BlockAlign;
waveFormat.Size = (short)Marshal.SizeOf(waveFormat);
waveProc = WaveOutProc;
if (Windows.WaveOutOpen(out device, Windows.WaveMapper, waveFormat, waveProc, 0, Windows.CallbackFunction) != 0)
{
DestroyAudio();
}
blockMemory = new short[blockCount * blockSamples];
waveHeaders = new WaveHdr[blockCount];
unsafe
{
fixed(short *mem = blockMemory)
{
for (uint n = 0; n < blockCount; n++)
{
waveHeaders[n].BufferLength = (int)(blockSamples * sizeof(short));
waveHeaders[n].Data = (IntPtr)(mem + (n * blockSamples));
}
}
}
Active = true;
audioThread = new Thread(AudioThread);
audioThread.Start();
}
/// <summary> Loads a wave file </summary>
/// <param name="reader"> Stream reader. </param>
/// <param name="isFromMp3"> Flag if converted from mp3 </param>
/// <returns> True if success, false if failed </returns>
private bool LoadFromWav(BinaryReader reader, bool isFromMp3 = false)
{
const string Riff = "RIFF";
const string Wave = "WAVE";
const string Fmt = "fmt ";
char[] dump;
dump = reader.ReadChars(4); // RIFF"
if (string.Compare(string.Concat(dump), Riff) != 0)
{
return(false);
}
dump = reader.ReadChars(4); // Ignore
dump = reader.ReadChars(4); // "WAVE"
if (string.Compare(string.Concat(dump), Wave) != 0)
{
return(false);
}
dump = reader.ReadChars(4); // "fmt "
if (string.Compare(string.Concat(dump), Fmt) != 0)
{
return(false);
}
dump = reader.ReadChars(4); // Ignore
WavHeader = new WaveFormatEx()
{
FormatTag = reader.ReadInt16(),
Channels = reader.ReadInt16(),
SamplesPerSec = reader.ReadInt32(),
AvgBytesPerSec = reader.ReadInt32(),
BlockAlign = reader.ReadInt16(),
BitsPerSample = reader.ReadInt16()
};
WavHeader.Size = (short)Marshal.SizeOf(WavHeader);
if (WavHeader.SamplesPerSec != 44100)
{
return(false);
}
const string Data = "data";
// Offset 2 characters to reach data.
// There are 2 extra chars while converting from mp3 for some reason ???
if (isFromMp3)
{
reader.ReadChars(2);
}
dump = reader.ReadChars(4); // Chunk header
long chunkSize = reader.ReadUInt32();
while (string.Compare(string.Concat(dump), Data) != 0)
{
reader.BaseStream.Seek(chunkSize, SeekOrigin.Current);
dump = reader.ReadChars(4);
chunkSize = reader.ReadUInt32();
}
SampleCount = chunkSize / (WavHeader.Channels * (WavHeader.BitsPerSample >> 3));
Channels = WavHeader.Channels;
Samples = new short[SampleCount * Channels];
const float Mult8Bit = (float)short.MaxValue / byte.MaxValue;
const float Mult24Bit = (float)short.MaxValue / (1 << 24);
const float Mult32Bit = (float)short.MaxValue / int.MaxValue;
for (long l = 0; l < Samples.Length; l++)
{
// Divide by 8 to convert to bits to bytes
switch (WavHeader.BitsPerSample / 8)
{
case 1: // 8-bits
byte b = reader.ReadByte();
Samples[l] = (short)(b * Mult8Bit);
break;
case 2: // 16-bits
short s = reader.ReadInt16();
Samples[l] = s;
break;
case 3: // 24-bits
byte[] bs = reader.ReadBytes(3);
int n = bs[0] | (bs[1] << 8) | (bs[2] << 16);
Samples[l] = (short)(n * Mult24Bit);
break;
case 4: // 32-bits
int i = reader.ReadInt32();
Samples[l] = (byte)(i * Mult32Bit);
break;
}
}
return(true);
}
