public UInt64 IsFormat(StreamReader.IReader fileReader, UInt64 offset, UInt64 length)
{
if (fileReader.Read_16bitsBE(offset) != 0x8000)
{
return(0);
}
// Check encoding type ...
if (fileReader.Read_8Bits(offset + 4) != 3)
{
return(0);
}
// Check Frame Size ...
if (fileReader.Read_8Bits(offset + 5) != 18)
{
return(0);
}
// Check Bit per Samples ...
if (fileReader.Read_8Bits(offset + 6) != 4)
{
return(0);
}
// Check for channel count & sample rate
uint sampleRate = fileReader.Read_32bitsBE(offset + 0x08);
uint channelCount = fileReader.Read_8Bits(offset + 0x07);
if (((channelCount <= 0) || (channelCount > 8)) ||
((sampleRate < 11025) || (sampleRate > 48000)))
{
return(0);
}
// Search for the (c)CRI signature ...
UInt64 criOffset = fileReader.Read_16bitsBE(offset + 2);
if ((fileReader.Read_32bitsBE(offset + criOffset - 4) != 0x00002863) &&
(fileReader.Read_32bitsBE(offset + criOffset) != 0x29435249))
{
return(0);
}
// Find file length ...
UInt32 totalSamples = fileReader.Read_32bitsBE(offset + 0x0C);
UInt64 searchOffset = offset + (totalSamples * channelCount) / 32 * 18 + criOffset + 4;
while (fileReader.Read_16bitsBE(searchOffset) != 0x8001)
{
searchOffset++;
if (!fileReader.CanRead())
{
break;
}
}
UInt64 fileLength = (searchOffset - offset) + fileReader.Read_16bitsBE(searchOffset + 2) + 4;
return(fileLength);
}
public void Init(StreamReader.IReader fileReader, UInt64 offset, ref VGM_Stream vgmStream, bool InitReader, UInt64 fileLength)
{
bool loop_flag = false;
UInt32 loop_start_sample = 0;
UInt32 loop_start_offset;
UInt32 loop_end_sample = 0;
UInt32 loop_end_offset;
Int16 coef1 = 0;
Int16 coef2 = 0;
UInt16 xor_start = 0;
UInt16 xor_mult = 0;
UInt16 xor_add = 0;
int i;
int channel_count = fileReader.Read_8Bits(offset + 0x07);
/* check version signature, read loop info */
UInt16 version_signature = fileReader.Read_16bitsBE(offset + 0x12);
UInt64 criOffset = (UInt64)(fileReader.Read_16bitsBE(offset + 2) + 4);
/* encryption */
if (version_signature == 0x0408)
{
if (!find_key(fileReader, offset, ref xor_start, ref xor_mult, ref xor_add))
{
return;
}
}
UInt32 ainf_info_length = 0;
if (fileReader.Read_32bitsBE(offset + 0x24) == 0x41494E46) /* AINF Header */
{
ainf_info_length = fileReader.Read_32bitsBE(offset + 0x28);
}
if (criOffset - ainf_info_length - 6 >= 0x38)
{ /* enough space for loop info? */
loop_flag = (fileReader.Read_32bitsBE(offset + 0x24) != 0);
loop_start_sample = (fileReader.Read_32bitsBE(offset + 0x28));
loop_start_offset = fileReader.Read_32bitsBE(offset + 0x2C);
loop_end_sample = fileReader.Read_32bitsBE(offset + 0x30);
loop_end_offset = fileReader.Read_32bitsBE(offset + 0x34);
}
/* build the VGMSTREAM */
VGM_Utils.allocate_vgmStream(ref vgmStream, channel_count, loop_flag);
vgmStream.vgmChannelCount = channel_count;
vgmStream.vgmSampleRate = (int)fileReader.Read_32bitsBE(offset + 0x08);
vgmStream.vgmTotalSamples = (int)fileReader.Read_32bitsBE(offset + 0x0C);
vgmStream.vgmDecoder = new ADXENC_Decoder();
if (channel_count == 1)
{
vgmStream.vgmLayout = new NoLayout();
}
else
{
vgmStream.vgmLayout = new Interleave();
}
vgmStream.vgmLoopFlag = loop_flag;
if (loop_flag)
{
vgmStream.vgmLoopStartSample = (int)loop_start_sample;
vgmStream.vgmLoopEndSample = (int)loop_end_sample;
}
/* high-pass cutoff frequency, always 500 that I've seen */
UInt16 cutoff = fileReader.Read_16bitsBE(offset + 0x10);
/* calculate filter coefficients */
{
double x, y, z, a, b, c;
x = cutoff;
y = vgmStream.vgmSampleRate;
z = Math.Cos(2.0 * Math.PI * x / y);
a = Math.Sqrt(2) - z;
b = Math.Sqrt(2) - 1.0;
c = (a - Math.Sqrt((a + b) * (a - b))) / b;
coef1 = (Int16)Math.Floor(c * 8192);
coef2 = (Int16)Math.Floor(c * c * -4096);
}
vgmStream.vgmInterleaveBlockSize = 18;
if (InitReader)
{
for (i = 0; i < channel_count; i++)
{
vgmStream.vgmChannel[i].fReader = (StreamReader.IReader)Activator.CreateInstance(fileReader.GetType());;
vgmStream.vgmChannel[i].fReader.Open(fileReader.GetFilename());
vgmStream.vgmChannel[i].fReader.SetSessionID(fileReader.GetSessionID());
vgmStream.vgmChannel[i].adpcm_coef[0] = coef1;
vgmStream.vgmChannel[i].adpcm_coef[1] = coef2;
vgmStream.vgmChannel[i].startOffset = vgmStream.vgmChannel[i].currentOffset = offset + criOffset + (UInt64)((vgmStream.vgmInterleaveBlockSize * i));
int j;
vgmStream.vgmChannel[i].adx_channels = channel_count;
vgmStream.vgmChannel[i].adx_xor = xor_start;
vgmStream.vgmChannel[i].adx_mult = xor_mult;
vgmStream.vgmChannel[i].adx_add = xor_add;
for (j = 0; j < i; j++)
{
VGM_Utils.adx_next_key(ref vgmStream.vgmChannel[i]);
}
}
}
}