// encoder functions
public static byte[] Encode(byte[] inWav)
{
byte loop = 0x02;
resample_var = 1.0;
resample_type = 'n';
FIRen = new bool[] { true, true, true, true };
FIRstats = new int[] { 0, 0, 0, 0 };
List <byte> outBrr = new List <byte>();
BRRBuffer = new byte[9]; //9 bytes long buffer
int offset = 0;
if (Bits.GetString(inWav, offset, 4) != "RIFF")
{
//"RIFF" letters
MessageBox.Show("Input file in unsupported format !");
return(null);
}
offset += 4;
offset += 4;
if (Bits.GetString(inWav, offset, 4) != "WAVE") //"WAVE letters
{
MessageBox.Show("Input file in unsupported format !");
return(null);
}
offset += 4;
if (Bits.GetString(inWav, offset, 4) != "fmt ") //"WAVE letters
{
MessageBox.Show("Input file in unsupported format !");
return(null);
}
offset += 4;
int sc1size = Bits.GetInt32(inWav, offset);
offset += 4;
if (sc1size < 0x10 || //Size of sub-chunk1 (header) must be at least 16
Bits.GetShort(inWav, offset) != 1 || //Must be in PCM format
Bits.GetShort(inWav, offset + 2) != 1)
{
//Must be in mono
MessageBox.Show("Input file in unsupported format !");
return(null);
}
offset += 4;
offset += 8; //ignore sample and byte rate
//Read block align and bits per sample numbers
short BlockAlign = (short)Bits.GetShort(inWav, offset); offset += 2;
short BitPerSample = (short)Bits.GetShort(inWav, offset); offset += 2;
if (BlockAlign != BitPerSample >> 3)
{
MessageBox.Show("Block align problem");
return(null);
}
offset += sc1size - 0x10;
//"data" letters for sub-chunk2
if (Bits.GetString(inWav, offset, 4) != "data")
{
MessageBox.Show("Input file in unsupported format");
return(null);
}
offset += 4;
int Sub2Size = Bits.GetInt32(inWav, offset); //Read sub-chunk 2 size
offset += 4;
short[] samples = new short[Sub2Size / BlockAlign];
switch (BitPerSample)
{
case 8:
short sample;
for (int i = 0; i < Sub2Size / BlockAlign; i++)
{
sample = (short)inWav[offset++]; //Convert 8-bit samples to 16-bit
sample -= 0x80;
samples[i] = (short)(sample << 8);
}
break;
case 16:
for (int i = 0; i < Sub2Size / BlockAlign; i++)
{
samples[i] = (short)(Bits.GetShort(inWav, offset));
offset += 2;
}
break;
default:
MessageBox.Show("Error : unsupported amount of bits per sample (8 or 16 are supported");
return(null);
}
samples = resample(samples, resample_type);
if ((samples.Length & 0xF) != 0)
{
MessageBox.Show("Warning ! The Amount of PCM samples isn't a multiple of 16 !");
MessageBox.Show("The sample will be padded with " + (0x10 - (samples.Length & 0x0F)) + " zeroes at the begining");
short[] a = new short[0x10 - (samples.Length & 0x0F)];
samples = append(a, samples);
}
bool init = false;
for (int i = 0; i < 16; i++)
{
init |= samples[i] != 0; //Initialization needed if any of the first 16 samples isn't zero
}
//Write initial BRR block
if (init)
{
outBrr.AddRange(new byte[] { loop, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 });
}
p1 = 0;
p2 = 0;
short[] samples2 = new short[16];
for (int n = 0; n < samples.Length >> 4; n++)
{
for (int i = 0; i < 16; i++)
{
samples2[i] = samples[i + (n << 4)]; //Read 16 samples
}
BRRBuffer = new byte[9];
ADPCMBlockMash(samples2); //Compute BRR block
BRRBuffer[0] |= loop; //Set the loop flag if needed
if (n == (samples.Length >> 4) - 1)
{
BRRBuffer[0] |= 1; //Set the end bit if we're on the last block
}
outBrr.AddRange(BRRBuffer);
}
return(outBrr.ToArray());
}
