public NwaDecoder(IBinaryStream input, NwaMetaData info)
{
m_input = input;
m_info = info;
m_output = new byte[m_info.PcmSize];
m_sample = new short[2];
m_bits = new LsbBitStream(input.AsStream, true);
}
public override SoundInput TryOpen(IBinaryStream file)
{
var header = file.ReadHeader(0x28);
ushort channels = header.ToUInt16(0);
if (0 == channels || channels > 2)
{
return(null);
}
ushort bps = header.ToUInt16(2);
if (bps != 8 && bps != 16)
{
return(null);
}
var info = new NwaMetaData
{
Compression = header.ToInt32(8),
RunLengthEncoded = 0 != header.ToInt32(0xC),
BlockCount = header.ToInt32(0x10),
PcmSize = header.ToInt32(0x14),
PackedSize = header.ToInt32(0x18),
SampleCount = header.ToInt32(0x1C),
BlockSize = header.ToInt32(0x20),
FinalBlockSize = header.ToInt32(0x24),
};
if (info.PcmSize <= 0)
{
return(null);
}
info.Format.FormatTag = 1;
info.Format.Channels = channels;
info.Format.BitsPerSample = bps;
info.Format.SamplesPerSecond = header.ToUInt32(4);
info.Format.BlockAlign = (ushort)(channels * bps / 8);
info.Format.AverageBytesPerSecond = info.Format.BlockAlign * info.Format.SamplesPerSecond;
if (-1 == info.Compression)
{
if (info.PcmSize > file.Length - 0x2C)
{
return(null);
}
return(new RawPcmInput(new StreamRegion(file.AsStream, 0x2C, info.PcmSize), info.Format));
}
if (info.Compression > 5)
{
return(null);
}
if (info.PcmSize != info.SampleCount * bps / 8)
{
return(null);
}
using (var decoder = new NwaDecoder(file, info))
{
decoder.Decode();
var pcm = new MemoryStream(decoder.Output);
var sound = new RawPcmInput(pcm, info.Format);
file.Dispose();
return(sound);
}
}
