//Coverted from C (ima_rejigger2)
//https://bitbucket.org/anders/wwiseconv/wiki/WWise_format
public static byte[] IMA_ADPCM(byte[] a, out string xex, bool pcm)
{
xex = "stream";
Binboy bb = new Binboy(a);
if(!bb.Open()) return a;
if (bb.GetEncoding().GetString(bb.ReadBytes(4), 0, 4) != "RIFF") return a;
int riffSize = bb.ReadInt32();
if (bb.GetEncoding().GetString(bb.ReadBytes(4), 0, 4) != "WAVE") return a;
int waveChunkStart = 12;
int waveChunkEnd = 8 + riffSize;
int chunkOffset = waveChunkStart;
int channels = -1;
int blockSize = -1;
int samples = -1;
int dataSize = -1;
int dataPos = -1;
bb.SetPosition(0);
MemoryStream ms = new MemoryStream(bb.ReadAllBytes());
BinaryWriter bw = new BinaryWriter(ms);
while (chunkOffset < waveChunkEnd)
{
bb.SetPosition((int)chunkOffset);
string chunkType = Encoding.ASCII.GetString(bb.ReadBytes(4), 0, 4);
int chunkSize = bb.ReadInt32();
if (chunkOffset + 8 + chunkSize < chunkOffset + 8 || chunkOffset + 8 + chunkSize > waveChunkEnd) return a;
switch (chunkType)
{
case "fmt ":
Bandaid.Debug("fmt");
if ((int)0xE > chunkSize) return a;
Bandaid.Debug("ChunkSize is correct");
ushort codec = bb.ReadUInt16(chunkOffset + 8);
if (codec == 0xFFFF)
{
xex = "stream";
return a;
}
if (0x2 != codec) return a;
Bandaid.Debug("Codec is correct");
channels = bb.ReadUInt16();
Bandaid.Debug("chunkOffset", chunkOffset);
samples = bb.ReadInt32();
bb.ReadUInt32();
ushort sblockSize = bb.ReadUInt16();
Bandaid.Debug("Channels", channels, "BlockSize", sblockSize);
blockSize = sblockSize;
bw.BaseStream.Position = chunkOffset + 8;
bw.Write((ushort)0x11);
break;
case "data":
Bandaid.Debug("Data");
if (channels < 1 || blockSize < 1) return a;
dataSize = chunkSize;
dataPos = chunkOffset + 8;
reinterleaveMS_IMA(bw, bb, dataPos, chunkSize, channels, blockSize);
break;
}
chunkOffset += 8 + chunkSize;
}
if (!pcm) return ms.ToArray();
ms.Position = 0;
IMA_ADPCM decode = new IMA_ADPCM(ms);
xex = "wav";
return decode.Decode();
}
//https://bitbucket.org/anders/wwiseconv/wiki/WWise_format
private static void reinterleaveMS_IMA(BinaryWriter bw, Binboy bb, int offset, int chunkSize, int channels, int blockSize)
{
int bytesPerChannel = blockSize / channels;
if (chunkSize % blockSize > 0) return;
if (blockSize % channels > 0) return;
if (bytesPerChannel % 4 > 0) return;
bb.SetPosition(offset);
byte[] buf = new byte[blockSize+1];
bw.BaseStream.Position = offset;
while (chunkSize > 0)
{
bb.SetPosition(offset);
bb.Stream.Read(buf, 0, blockSize);
bb.SetPosition(offset);
for (int i = 0; i < channels; ++i)
{
bw.Write(buf, i * bytesPerChannel, 4);
}
for (int j = 0; j < bytesPerChannel - 4; j += 4)
{
for (int i = 0; i < channels; ++i)
{
bw.Write(buf, (i * bytesPerChannel + 4) + j, 4);
}
}
chunkSize -= blockSize;
offset += blockSize;
}
}