How can I recording to WAV file in unsigned 8-bits PCM mono format?

[hash6iron]

How can I recording to WAV file in unsigned 8-bits PCM mono format?
I try setting encoder as code below, but not working.

    File32 wavfile;
    ...
    EncodedAudioStream encoder(&wavfile, new WAVEncoder());
    AudioInfo ecfg = encoder.defaultConfig();
    ecfg.sample_rate = 22050;
    ecfg.bits_per_sample = 8;
    ecfg.channels = 1;```
    
    encoder.begin(ecfg);

[pschatzmann]

You will need to convert the provided data format to 8 bit!

If I remember right WAV expects uint8_t instead of int8_t!

[hash6iron]

Hi again @pschatzmann,

I try to code but I'm doing something wrong because the audio is not fine.
kitStream is "Line In" input of AudioKit A1S

NOTE: This is only a piece of my code. Line in recording to WAV works fine without NumberFormatConverterStream

  AudioBoardStream kitStream(powadcr_board);
  ...
  EncodedAudioStream encoder(&wavfile, new WAVEncoder());
  AudioInfo enc_sr = encoder.defaultConfig();
  
  NumberFormatConverterStreamT<int16_t, uint8_t> nfc(kitStream);
  StreamCopy copier8bit(encoder, nfc);
  ...
  nfc.begin()

Attached files with and without conversion.
samples.zip

[pschatzmann]

I think you just forgot to tell the EncodedAudioStream that it is 8 bits: so you write 8 bit data and tell the WAV header that it is 16 bit...

[hash6iron]

How can I do it?

[pschatzmann]

by defining the bits_per_sample in enc_sr

[hash6iron]

Ok..I understand.

Inline of this issue. How can I record with encoded PCM to WAV file? I try with objects chain without success.

[pschatzmann]

By implementing one of the following chains:

• AudioBoardStream -copy > NumberFormatConverterStreamT -> EncodedAudioStream -> File
• AudioBoardStream -> NumberFormatConverterStreamT - copy -> EncodedAudioStream -> File

If you use the second option, you need to provide the correct format to the EncodedAudioStream (as mentioned above) or have the StreamCopy synchronize the fomrat using copier.setSynchAudioInfo(true)

[hash6iron]

Hi @pschatzmann.

I don´t achieve a good WAV quality. continue with strange recording, besides, the sound appears like an accelerated. This following I have done.

Do your see any wrong in the code?
Thanks in advance.

void WavRecording()
{
  AudioInfo new_sr = kitStream.defaultConfig();
  new_sr.sample_rate = 22050;
  kitStream.setAudioInfo(new_sr);       

  const size_t BUFFER_SIZE = 4096;
  int16_t buffer[BUFFER_SIZE];

  EncodedAudioStream encoder(&wavfile, new WAVEncoder());
  NumberFormatConverterStreamT<int16_t, uint8_t> nfc(kitStream);
  StreamCopy copier8bWAV(encoder, nfc);

  // Encoder setup
  AudioInfo ecfg = encoder.defaultConfig();
  ecfg.sample_rate = 22050;
  ecfg.bits_per_sample = 8; 
  ecfg.channels = 1; // Mono


  encoder.begin(ecfg);
  nfc.begin();

  kitStream.setPAPower(false); 
  copier.setSynchAudioInfo(true);

  copier8bWAV.begin();

  // recorder loop
  while (!STOP)
  {
      copier8bWAV.copy();   
  }

  copier8bWAV.end();
  encoder.end();
  nfc.end();

  // Cerramos el fichero WAV
  wavfile.flush();
  wavfile.close();
}

[hash6iron]

Sorry. Now works fine but How can I do to record on mono mode?

[pschatzmann]

You forgot new_sr.channels = 1;

[hash6iron]

Now, I try to replicate this above to player playing but the first time WAV sampling rate propagate well, but the second playing the sampling rate keeps at 44.1KHz. How can I do to propagate sampling rate to kitStream always using PLAYER object instead of COPIER?

[pschatzmann]

Please read the documentaion and set the logger to info to follow what's going on...