[Speex-dev] WaveIn/WaveOut and Speex

Evgueni Tsygankov eugenet at rusmex.com
Sun Nov 4 18:50:29 PST 2007



I know my question has been asked before because I spent the last week
searching the web for how to use Speex in combination with
WaveIn/WaveOut and I ran into a few posts, but none of them answer the
question. There is still a lot of confusion how to use WaveIn/WaveOut
and Speex by junior developers such as myself. Even after examining code
for SpeexDec and SpeexEnc, I cannot get clear sound when I try to


Get PCM Char buffer from the microphone

Encode Char buffer using Speex

Decode Speex Char buffer into PCM char buffer

Play PCM char buffer using WaveOut


The end-result is very distorted sound.



I use the following PCM format:


waveFormat.nChannels = 1;

waveFormat.nSamplesPerSec = 8000;

waveFormat.wBitsPerSample = 8;


Once sound is aquired by the mic, I send it to Speex in a Char buffer.
It looks something like this:


Encode(char* inBuffer, DWORD bufferLength)


float* input = new float[frameSize];

ZeroMemory(input, frameSize);


for(    )


input[..] = inBuffer[..];



speex_encode(enc_state, input, &bits);

int bytesWritten = speex_bits_nbytes(&bits);

speex_bits_write(&bits, encBuffer, bytesWritten);




Then, my decoding routine accepts the char buffer that was encoded with


Decode(char* encBuffer, DWORD bufferLength)


float* output = new float[frameSize];


speex_bits_read_from(&bits, encBuffer + offset, bytesToRead);

speex_decode(dec_state, &bits, output);


char* outBuffer=...

for(UINT i = 0; i < frameSize; i++)


outBuffer[retValIndex] = output[i];




When I try to play outBuffer with waveOut, I can hear the voice
"somewhere far", but there is a lot of distortion noise. Any help would
be greatly appreciated!!!


Thank you,


Evgueni Tsygankov

www.sqlanswers.com <http://www.sqlanswers.com/> 


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