protected override bool BufferData(Stream baseStream, Queue <byte> data)
{
if (dataSize <= 0)
{
return(true);
}
var chunk = ImaAdpcmChunk.Read(baseStream);
for (var n = 0; n < chunk.CompressedSize; n++)
{
var b = baseStream.ReadUInt8();
var t = ImaAdpcmReader.DecodeImaAdpcmSample(b, ref index, ref currentSample);
data.Enqueue((byte)t);
data.Enqueue((byte)(t >> 8));
baseOffset += 2;
if (baseOffset < outputSize)
{
/* possible that only half of the final byte is used! */
t = ImaAdpcmReader.DecodeImaAdpcmSample((byte)(b >> 4), ref index, ref currentSample);
data.Enqueue((byte)t);
data.Enqueue((byte)(t >> 8));
baseOffset += 2;
}
}
dataSize -= 8 + chunk.CompressedSize;
return(dataSize <= 0);
}
// Reference: https://github.com/dbry/adpcm-xq/blob/master/adpcm-lib.c
public IList <ISound> Decode(ImaAdpcmChunk chunk)
{
var sounds = new List <ISound>();
var buffer = new float[chunk.ChannelSamplesPerFrame];
var channels = chunk.Channels;
var frameSize = (chunk.ChannelSamplesPerFrame * chunk.Channels / 2) + (chunk.Channels * 4);
var max = (chunk.Data.Length / frameSize) * frameSize;
var output = Enumerable.Range(0, channels).Select(i => new List <float>()).ToArray();
for (var offset = 0; offset < max; offset += frameSize)
{
var mem = chunk.Data.AsSpan(offset, frameSize);
for (var channel = 0; channel < channels; channel++)
{
DecodeFrame(mem, buffer, channel, channels);
output[channel].AddRange(buffer);
}
}
sounds.Add(new Sound
{
Samples = output.Select(s => new Sample {
Data = s
}).Cast <ISample>().ToList()
});
return(sounds);
}
public void TestXboxAdpcm()
{
var decoder = Resolve <IImaAdpcmDecoder>();
var encoder = Resolve <IRiffPcm16SoundEncoder>();
var writer = Resolve <IRiffStreamWriter>();
var data = GetArchiveResource($"ImaAdpcm.RawXboxAdpcm.zip")
.First()
.Value;
var ima = new ImaAdpcmChunk
{
Channels = 2,
ChannelSamplesPerFrame = 64,
Data = data,
Rate = 44100
};
var decoded = decoder.Decode(ima);
var index = 0;
foreach (var sound in decoded)
{
sound[NumericData.Rate] = ima.Rate;
var encoded = encoder.Encode(sound);
var outfolder = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "ima");
if (!Directory.Exists(outfolder))
{
Directory.CreateDirectory(outfolder);
}
using (var outStream = new MemoryStream())
{
writer.Write(outStream, encoded);
outStream.Flush();
File.WriteAllBytes(Path.Combine(outfolder, $"{index:000}.wav"), outStream.ToArray());
index++;
}
}
}