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Carine Liang

2006-Nov-02 00:22 UTC

[Speex-dev] Integrating speex with VideoNet application: Constantbackground noise

Hi John,

Thanks for your reply. 

Yes, my output device is in 8-bit mode, same as my input mode. I'm actually
working in char (8 bit) arrays. Is it necessary to work in signed short integers
only? I changed all the short arrays in the example to char.

Carine

----- Original Message ----
From: John Miles <jmiles@pop.net>
To: carineliang@yahoo.com.sg; speex-dev@xiph.org
Sent: Thursday, 2 November 2006 2:04:39 PM
Subject: RE: [Speex-dev] Integrating speex with VideoNet application:
Constantbackground noise



 
DIV {
MARGIN:0px;}



At 
first glance it looks like you are opening the output device in 8-bit mode
(m_waveFormatEx.wBitsPerSample
=8;).  You will need to use 16-bit 
mode if you expect to write an array of signed short integers to the audio 
buffer.  8-bit PCM is an unsigned mode, no longer used much these 
days.

 

Also, 
a good debugging trick is to include something like this in your output sample 
processing loop:

 

    static FILE *hack = 
fopen("test.raw","wb");

    fwrite(output, 2, FRAME_SIZE, 
hack);

 

After your app is closed, there will be a file called "test.raw" in 
its working directory, which you can load into Sound Forge or a similar audio 
editing package for closer inspection without relying on your output 
buffers and playback code to work properly.  

 

-- 
john

RAD 
Game Tools


  -----Original Message-----
From: speex-dev-bounces@xiph.org 
  [mailto:speex-dev-bounces@xiph.org]On Behalf Of Carine 
  Liang
Sent: Wednesday, November 01, 2006 9:40 PM
To: 
  speex-dev@xiph.org
Subject: Re: [Speex-dev] Integrating speex with 
  VideoNet application: Constantbackground noise



  
  Hi,

Can 
  someone please help me with my problem below. Any suggestions is appreciated. 
  

thanks,
Carine


  ----- 
  Original Message ----
From: Carine Liang 
  <carineliang@yahoo.com.sg>
To: speex-dev@xiph.org; 
  speex-dev@xiph.org
Sent: Tuesday, 31 October 2006 1:05:49 PM
Subject: 
  [Speex-dev] Integrating speex with VideoNet application: Constant background 
  noise


  
  Hi,

I am developing a peer-to-peer video conference application 
  which uses speex as a codec for the voice. 

I am new to speex, so 
  please bear with me if I asked the obvious. After I added the encode and 
  decode function to my MFC app, I heard a constant background noise, even when 
  no one is speaking into the microphone. 

#define FRAME_SIZE 
  160

The application is coded in MFC C++. The record buffer is set to be 
  the same as the FRAME_SIZE such that my callback function is called everytime 
  160 bytes of data is recorded.

Here's what I did in the initialisation 
  (called only once).
m_waveFormatEx.wFormatTag 
  =WAVE_FORMAT_PCM;
m_waveFormatEx.nChannels 
  =1;
m_waveFormatEx.wBitsPerSample =8;
m_waveFormatEx.cbSize 
  =0;
m_waveFormatEx.nSamplesPerSec = 8000;
m_waveFormatEx.nBlockAlign 
  =1;
m_waveFormatEx.nAvgBytesPerSec = 8000;

int quality 
  =8;
speex_bits_init(&bits);
enc_state = 
  speex_encoder_init(&speex_nb_mode);
speex_encoder_ctl(enc_state, 
  SPEEX_SET_QUALITY, &quality);


In my recording callback 
  function
LRESULT RecordSound::OnSoundData(WPARAM wParam, LPARAM 
  lParam)
{
 ....
    dataPtr = (char *)lpHdr 
  ->lpData;
    dataSize = (int)lpHdr 
  ->dwBytesRecorded;

    for(int 
  k=0;k<FRAME_SIZE;k++)
       input[k] = 
  dataPtr[k];     //input is 
  float[FRAME_SIZE]
    
    
  speex_bits_reset(&bits);
    speex_encode(enc_state, 
  input, &bits);
    encByte = speex_bits_write(&bits, 
  cbits, 200);

    //send cbits to peer computer via 
  sockets
}


In the receiver's initialization function, I've 
  initialized the speex_decoder.
speex_bits_init(&bits);
dec_state = 
  speex_decoder_init(&speex_nb_mode);

In the receiver's socket 
  function, it reads from socket and store the data in cbits (char 
  array).
{
    speex_bits_read_from(&bits, cbits, 
  retvalue); //retvalue is 38
    speex_decode(dec_state, 
  &bits, output); //where output is float array

    
  for(int k=0;k<FRAME_SIZE;k++)
       out[k] = 
  output[k];  //out is a char array
    
   
  PostThreadMessage( WM_PLAYSOUND_PLAYBLOCK, FRAME_SIZE, (LPARAM)out 
  );
}







  
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Contribute to the Yahoo! Time Capsule and be a part of internet 
  history.
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  list
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John Miles

2006-Nov-02 08:42 UTC

head link

[Speex-dev] Integrating speex with VideoNet application: Constantbackground noise

Yes, it's necessary; Speex will encode signed 16-bit PCM data and decode to
the same format.  See the examples that come with it.

8-bit audio is not something you would ever want to use.

-- john
RAD Game Tools
  -----Original Message-----
  From: Carine Liang [mailto:carineliang@yahoo.com.sg]
  Sent: Thursday, November 02, 2006 12:18 AM
  To: John Miles; speex-dev@xiph.org
  Subject: Re: [Speex-dev] Integrating speex with VideoNet application:
Constantbackground noise


  Hi John,

  Thanks for your reply.

  Yes, my output device is in 8-bit mode, same as my input mode. I'm
actually working in char (8 bit) arrays. Is it necessary to work in signed
short integers only? I changed all the short arrays in the example to char.

  Carine


  ----- Original Message ----
  From: John Miles <jmiles@pop.net>
  To: carineliang@yahoo.com.sg; speex-dev@xiph.org
  Sent: Thursday, 2 November 2006 2:04:39 PM
  Subject: RE: [Speex-dev] Integrating speex with VideoNet application:
Constantbackground noise


  At first glance it looks like you are opening the output device in 8-bit
mode (m_waveFormatEx.wBitsPerSample =8;).  You will need to use 16-bit mode
if you expect to write an array of signed short integers to the audio
buffer..  8-bit PCM is an unsigned mode, no longer used much these days.

  Also, a good debugging trick is to include something like this in your
output sample processing loop:

      static FILE *hack = fopen("test.raw","wb");
      fwrite(output, 2, FRAME_SIZE, hack);

  After your app is closed, there will be a file called "test.raw" in
its
working directory, which you can load into Sound Forge or a similar audio
editing package for closer inspection without relying on your output buffers
and playback code to work properly.

  -- john
  RAD Game Tools
    -----Original Message-----
    From: speex-dev-bounces@xiph.org [mailto:speex-dev-bounces@xiph.org]On
Behalf Of Carine Liang
    Sent: Wednesday, November 01, 2006 9:40 PM
    To: speex-dev@xiph.org
    Subject: Re: [Speex-dev] Integrating speex with VideoNet application:
Constantbackground noise


    Hi,

    Can someone please help me with my problem below. Any suggestions is
appreciated.

    thanks,
    Carine


    ----- Original Message ----
    From: Carine Liang <carineliang@yahoo.com.sg>
    To: speex-dev@xiph.org; speex-dev@xiph.org
    Sent: Tuesday, 31 October 2006 1:05:49 PM
    Subject: [Speex-dev] Integrating speex with VideoNet application:
Constant background noise


    Hi,

    I am developing a peer-to-peer video conference application which uses
speex as a codec for the voice.

    I am new to speex, so please bear with me if I asked the obvious. After
I added the encode and decode function to my MFC app, I heard a constant
background noise, even when no one is speaking into the microphone.

    #define FRAME_SIZE 160

    The application is coded in MFC C++. The record buffer is set to be the
same as the FRAME_SIZE such that my callback function is called everytime
160 bytes of data is recorded.

    Here's what I did in the initialisation (called only once).
    m_waveFormatEx.wFormatTag =WAVE_FORMAT_PCM;
    m_waveFormatEx.nChannels =1;
    m_waveFormatEx.wBitsPerSample =8;
    m_waveFormatEx.cbSize =0;
    m_waveFormatEx.nSamplesPerSec = 8000;
    m_waveFormatEx.nBlockAlign =1;
    m_waveFormatEx.nAvgBytesPerSec = 8000;

    int quality =8;
    speex_bits_init(&bits);
    enc_state = speex_encoder_init(&speex_nb_mode);
    speex_encoder_ctl(enc_state, SPEEX_SET_QUALITY, &quality);


    In my recording callback function
    LRESULT RecordSound::OnSoundData(WPARAM wParam, LPARAM lParam)
    {
     ....
        dataPtr = (char *)lpHdr ->lpData;
        dataSize = (int)lpHdr ->dwBytesRecorded;

        for(int k=0;k<FRAME_SIZE;k++)
           input[k] = dataPtr[k];     //input is float[FRAME_SIZE]

        speex_bits_reset(&bits);
        speex_encode(enc_state, input, &bits);
        encByte = speex_bits_write(&bits, cbits, 200);

        //send cbits to peer computer via sockets
    }


    In the receiver's initialization function, I've initialized the
speex_decoder.
    speex_bits_init(&bits);
    dec_state = speex_decoder_init(&speex_nb_mode);

    In the receiver's socket function, it reads from socket and store the
data in cbits (char array).
    {
        speex_bits_read_from(&bits, cbits, retvalue); //retvalue is 38
        speex_decode(dec_state, &bits, output); //where output is float
array

        for(int k=0;k<FRAME_SIZE;k++)
           out[k] = output[k];  //out is a char array

       PostThreadMessage( WM_PLAYSOUND_PLAYBLOCK, FRAME_SIZE, (LPARAM)out );
    }






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