Silverlight Speex playing at fast rate - audio

Question

I'm using Speex to encode the raw data but after I decode the data the audio plays at a faster rate because it makes you sound like a chipmunk. I'm using NSpeex and Silverlight 4.
8kHz Sampling
Encoding Function:
JSpeexEnc encoder = new JSpeexEnc();
int rawDataSize = 0;
public byte[] EncodeAudio(byte[] rawData)
{
var encoder = new SpeexEncoder(BandMode.Narrow);
var inDataSize = rawData.Length / 2;
var inData = new short[inDataSize];
for (var index = 0; index < rawData.Length; index += 2)
{
inData[index / 2] = BitConverter.ToInt16(rawData, index);
}
inDataSize = inDataSize - inDataSize % encoder.FrameSize;
var encodedData = new byte[rawData.Length];
var encodedBytes = encoder.Encode(inData, 0, inDataSize, encodedData, 0, encodedData.Length);
byte[] encodedAudioData = null;
if (encodedBytes != 0)
{
encodedAudioData = new byte[encodedBytes];
Array.Copy(encodedData, 0, encodedAudioData, 0, encodedBytes);
}
rawDataSize = inDataSize; // Count of encoded shorts, for debugging
return encodedAudioData;
}
Decoding Function:
SpeexDecoder decoder = new SpeexDecoder(BandMode.Narrow);
public byte[] Decode(byte[] encodedData)
{
try
{
short[] decodedFrame = new short[8000]; // should be the same number of samples as on the capturing side
int decoderBytes = decoder.Decode(encodedData, 0, encodedData.Length, decodedFrame, 0, false);
byte[] decodedData = new byte[encodedData.Length];
byte[] decodedAudioData = null;
decodedAudioData = new byte[decoderBytes * 2];
for (int shortIndex = 0, byteIndex = 0; byteIndex < decoderBytes; shortIndex++)
{
BitConverter.GetBytes(decodedFrame[shortIndex + byteIndex]).CopyTo(decodedAudioData, byteIndex * 2);
byteIndex++;
}
// todo: do something with the decoded data
return decodedAudioData;
}
catch (Exception ex)
{
ShowMessageBox(ex.Message.ToString());
return null;
}
}
Playing the audio:
void PlayWave(byte[] PCMBytes)
{
byte[] decodedBuffer = Decode(PCMBytes);
MemoryStream ms_PCM = new MemoryStream(decodedBuffer);
MemoryStream ms_Wave = new MemoryStream();
_pcm.SavePcmToWav(ms_PCM, ms_Wave, 16, 8000, 1);
WaveMediaStreamSource WaveStream = new WaveMediaStreamSource(ms_Wave);
mediaElement1.SetSource(WaveStream);
mediaElement1.Play();
}

Answer 1

Sorry guys for the late response but I figured out what the problem was.
Inside my decode function I loop through the decoded short array but I'm only copying half of the bytes into my new byte array.
It needs to look something like this:
decodedAudioData = new byte[decoderBytes * 2];
for (int shortIndex = 0, byteIndex = 0; shortIndex < decodedFrame.Length; shortIndex++, byteIndex += 2)
{
byte[] temp = BitConverter.GetBytes(decodedFrame[shortIndex]);
decodedAudioData[byteIndex] = temp[0];
decodedAudioData[byteIndex + 1] = temp[1];
}