C# and wave - how do I process 20ms of audio data

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C#

audio

bytes

Hi all,

I'm having issues with achieving something I'm sure you guys can assist.
I'm trying to iterate over a Wave file and process 20ms of the audio data each time. However, I'm getting confused with the bytes arrays and conversions and I'd be grateful if someone can assist on this with examples...

At the end I will need to handle several types (2-channels, 16Khz etc.) but for now I have a ready 8000hz, 1 channel 16bit file.

I'm using NAudio for reading the file.

What I have tried:

/*
Pcm 8000Hz 1 channels 16 bits per sample
Extra Size: 0 Block Align: 2 Average Bytes Per Second: 16000
WaveFormat: 16 bit PCM: 8kHz 1 channels
Length: 351360 bytes: 00:00:21.9600000 
*/

WaveFileReader wHeader= new WaveFileReader(FullFileName);

byte[] data = new byte[wHeader.Length];
int read = wHeader.Read(data, 0, data.Length);  //Length = 351360
short[] shortBuffer = new short[read / 2]; // = 175680
int tBuf = 159; //Not sure this is 20ms?
short[] InpBuf = new short[tBuf]; //This is the 20ms inputBuffer I will process
int offst = 0;

Buffer.BlockCopy(data, 0, shortBuffer, 0, data.Length);


for (int i = 0; i < read; i += 2)
            {
                Buffer.BlockCopy(shortBuffer , offst, InpBuf, 0, tBuf);  //I'm taking the tBuf (=159) data from the full shortBuffer into InpBuf (with offset of 0)
                offst += tBuf+1; //advancing the next offset from 0 to 160

                Process20ms(InpBuf);  //now I can process the 20ms of data

                Array.Clear(InpBuf, 0, InpBuf.Length); //resetting the InpBuf for the next iteration
            }

Anyways, this doesn't work well, when I'm comparing the inpBuf chunks to the full shortBuffer I can see that the data in inpBuf[0] to inpBufp[78] is identical, but afterwards i get 00000 till inpBuf[159].
After inpBuf[160] I'm getting totally different data.

So, I'm confused with the Byte, Short, Blockcopy and samples, although it sounds very easy to achieve once I have the full audio data array.

Once I understand this I believe it will be much easier to process Stereo (2 channels) files as well.

Thanks...