Recording and playing MP3 audio - mp3

Question

I have followed the different threads on how to record and play MP3 but I still always get this exception trying to play MP3 files that I have recorded:
mp3filereader does not support sample rate changes
So here is my code to record :
waveInStream = new WaveIn();
waveInStream.WaveFormat = new WaveFormat(8000, 16, 1);
writer = new WaveFileWriter(outputfileName, waveInStream.WaveFormat);
waveInStream.DataAvailable += new EventHandler<WaveInEventArgs>(waveInStream_DataAvailable);
waveInStream.StartRecording();
The waveInStream_DataAvailable is :
void waveInStream_DataAvailable(object sender, WaveInEventArgs e)
{
writer.Write(e.Buffer, 0, e.BytesRecorded);
}
At this point the recorded file should be PCM uncompressed right?
Do I need to transcode it to MP3 before being able to play it?
My playing code:
WaveChannel32 inputStream;
WaveStream mp3Reader = new Mp3FileReader(fileName); var pStream = NAudio.Wave.WaveFormatConversionStream.CreatePcmStream(mp3Reader);
inputStream = new WaveChannel32(mp3Reader);
volumeStream = inputStream;
return volumeStream;
The exception occurs every time at the call of Mp3FileReader and says something like:
Got a frame at sample rate 44100, in a MP3 sample rate 32000
Mp3FileReader does not support sample rate change

Answer 1

Yes, you have saved a WAV file, not an MP3 file. Either convert to MP3 using something like LAME.exe, or just use the WaveFileReader instead of the Mp3FileReader. MP3 doesn't really support low sample rates like 8kHz in any case, which is typically only used for telephony.