public int Encode(byte[] inputBuffer, int inputBufferOffset, int dataLength, byte[] outputBuffer,
int outputBufferOffset, int quality)
{
var compressedSize = 0;
var speexBits = new Speex.SpeexBits();
var compressedBits = new byte[MAX_FRAME_SIZE];
var unmanagedStorage = IntPtr.Zero;
try
{
var encoderState = IntPtr.Zero;
unmanagedStorage = Marshal.AllocHGlobal(4);
try
{
var mode = Speex.speex_lib_get_mode(Speex.SPEEX_MODEID_NB);
var header = new Speex.SpeexHeader();
const int rate = 8000;
Speex.speex_init_header(ref header, rate, 1, mode);
header.frames_per_packet = 1;
header.vbr = 0;
header.nb_channels = 1;
encoderState = Speex.speex_encoder_init(mode);
Speex.speex_encoder_ctl(encoderState, Speex.SPEEX_GET_FRAME_SIZE, unmanagedStorage);
var frameSize = Marshal.ReadInt32(unmanagedStorage);
const int complexity = 10;
Marshal.WriteInt32(unmanagedStorage, complexity);
Speex.speex_encoder_ctl(encoderState, Speex.SPEEX_SET_COMPLEXITY, unmanagedStorage);
Marshal.WriteInt32(unmanagedStorage, rate);
Speex.speex_encoder_ctl(encoderState, Speex.SPEEX_SET_SAMPLING_RATE, unmanagedStorage);
Marshal.WriteInt32(unmanagedStorage, quality);
Speex.speex_encoder_ctl(encoderState, Speex.SPEEX_SET_QUALITY, unmanagedStorage);
const int lookahead = 0;
Marshal.WriteInt32(unmanagedStorage, lookahead);
Speex.speex_encoder_ctl(encoderState, Speex.SPEEX_GET_LOOKAHEAD, unmanagedStorage);
Speex.speex_bits_init(ref speexBits);
var input = new byte[MAX_FRAME_SIZE];
using (var inStream = new MemoryStream(inputBuffer, inputBufferOffset, dataLength))
using (
var outStream = new MemoryStream(outputBuffer, outputBufferOffset,
outputBuffer.Length - outputBufferOffset))
{
while (true)
{
var pcmBytesToRead = 16 / 8 * header.nb_channels * frameSize;
var numBytesRead = inStream.Read(input, 0, pcmBytesToRead);
if (numBytesRead == 0)
{
break;
}
var numSamplesToBlank = (pcmBytesToRead - numBytesRead) / (16 / 8 * header.nb_channels);
var numSamplesRead = numBytesRead / (16 / 8 * header.nb_channels);
for (var i = numSamplesRead; i < numSamplesRead + numSamplesToBlank; i++)
{
input[(i * 2)] = 0;
input[(i * 2) + 1] = 0;
}
var thisFrameBytesAsShort = new short[input.Length / 2];
for (var i = 0; i < thisFrameBytesAsShort.Length; i++)
{
thisFrameBytesAsShort[i] = BitConverter.ToInt16(input, (i * 2));
}
Speex.speex_encode_int(encoderState, thisFrameBytesAsShort, ref speexBits);
Speex.speex_bits_insert_terminator(ref speexBits);
var numBytesEncodedThisFrame =
(byte)Speex.speex_bits_write(ref speexBits, compressedBits, MAX_FRAME_SIZE);
Speex.speex_bits_reset(ref speexBits);
outStream.WriteByte(numBytesEncodedThisFrame);
compressedSize += 1;
outStream.Write(compressedBits, 0, numBytesEncodedThisFrame);
compressedSize += numBytesEncodedThisFrame;
}
}
}
finally
{
Speex.speex_encoder_destroy(encoderState);
Speex.speex_bits_destroy(ref speexBits);
}
}
finally
{
Marshal.FreeHGlobal(unmanagedStorage);
}
return(compressedSize);
}
public int Decode(byte[] inputBuffer, int inputBufferOffset, int dataLength, ref byte[] outputBuffer,
int outputBufferOffset)
{
var speexBits = new Speex.SpeexBits();
var decoderState = IntPtr.Zero;
var bytesWritten = 0;
var compressedBits = new byte[200];
var decompressedBits = new short[MAX_FRAME_SIZE];
var unmanagedStoragePointer = IntPtr.Zero;
var compressedBitsGCHandle = new GCHandle();
var decompressedBitsGCHandle = new GCHandle();
try
{
unmanagedStoragePointer = Marshal.AllocHGlobal(4);
compressedBitsGCHandle = GCHandle.Alloc(compressedBits, GCHandleType.Pinned);
decompressedBitsGCHandle = GCHandle.Alloc(decompressedBits, GCHandleType.Pinned);
try
{
Speex.speex_bits_init(ref speexBits);
var mode = Speex.speex_lib_get_mode(Speex.SPEEX_MODEID_NB);
decoderState = Speex.speex_decoder_init(mode);
Marshal.WriteInt32(unmanagedStoragePointer, 0);
Speex.speex_decoder_ctl(decoderState, Speex.SPEEX_SET_ENH, unmanagedStoragePointer);
Speex.speex_decoder_ctl(decoderState, Speex.SPEEX_GET_FRAME_SIZE, unmanagedStoragePointer);
var frameSize = Marshal.ReadInt32(unmanagedStoragePointer);
const int rate = 8000;
Marshal.WriteInt32(unmanagedStoragePointer, rate);
Speex.speex_decoder_ctl(decoderState, Speex.SPEEX_SET_SAMPLING_RATE, unmanagedStoragePointer);
Speex.speex_decoder_ctl(decoderState, Speex.SPEEX_GET_LOOKAHEAD, unmanagedStoragePointer);
var lookahead = Marshal.ReadInt32(unmanagedStoragePointer);
using (var inStream = new MemoryStream(inputBuffer, inputBufferOffset, dataLength))
using (
var outstream = new MemoryStream(outputBuffer, outputBufferOffset,
outputBuffer.Length - outputBufferOffset))
{
while (true)
{
var numBytesThisFrame = inStream.ReadByte();
if (numBytesThisFrame < 1)
{
break;
}
var bytesRead = inStream.Read(compressedBits, 0, numBytesThisFrame);
if (bytesRead < numBytesThisFrame)
{
throw new IOException("Unexpected end of stream encountered.");
}
Speex.speex_bits_read_from(ref speexBits, compressedBits, numBytesThisFrame);
var returnVal = Speex.speex_decode_int(decoderState, ref speexBits, decompressedBits);
var bitsRemaining = Speex.speex_bits_remaining(ref speexBits);
if (returnVal == -1)
{
break;
}
if (returnVal == -2)
{
throw new IOException("Decoding error: corrupted stream?\n");
}
else if (bitsRemaining < 0)
{
throw new IOException("Decoding overflow: corrupted stream?\n");
}
for (var i = 0; i < frameSize; i++)
{
if (outstream.Position > outstream.Length - 2)
{
break;
}
outstream.Write(BitConverter.GetBytes(decompressedBits[i]), 0, 2);
bytesWritten += 2;
}
}
outstream.Flush();
outstream.Close();
inStream.Close();
}
}
finally
{
Speex.speex_decoder_destroy(decoderState);
Speex.speex_bits_destroy(ref speexBits);
}
}
finally
{
Marshal.FreeHGlobal(unmanagedStoragePointer);
compressedBitsGCHandle.Free();
decompressedBitsGCHandle.Free();
//modeGCHandle.Free();
}
return(bytesWritten);
}
