[Speex-dev] Integrating speex with VideoNet application:
Constantbackground noise
Carine Liang
carineliang at yahoo.com.sg
Sun Dec 24 17:21:18 PST 2006
Hi,
I'm still unable to get rid of the background noise though I've changed
the PCM samples to 16 bit.
I'm began to wonder if I can just take the PCM samples and encode them.
What my application tries to do is to record the voice from a microphone, encode it, send it via the socket to a peer, decode at the peer's side and play the voice. My application works fine without the codec but I need to achieve a lower data rate. Anyone has done that before?
Is there anyone who's deal with encoding and
decoding PCM samples in windows?
Please help.
Carine
----- Original Message ----
From: John Miles <jmiles at pop.net>
To: Carine Liang <carineliang at yahoo.com.sg>; speex-dev at xiph.org
Sent: Friday, 3 November 2006 12:32:43 AM
Subject: RE: [Speex-dev] Integrating speex with VideoNet application: Constantbackground noise
DIV {
MARGIN:0px;}
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 at yahoo.com.sg]
Sent: Thursday, November 02, 2006
12:18 AM
To: John Miles; speex-dev at 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 at pop.net>
To:
carineliang at yahoo.com.sg; speex-dev at 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 at xiph.org
[mailto:speex-dev-bounces at xiph.org]On Behalf Of Carine
Liang
Sent: Wednesday, November 01, 2006 9:40 PM
To:
speex-dev at 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 at yahoo.com.sg>
To: speex-dev at xiph.org;
speex-dev at 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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