Re: how to use the buffer from sound card

[Marek Michalak <michalak.marek@xxxxxxxxx>]

Ok, It's resolved. It works well when: 

size =1;
signed int value;

while (PERIOD_SIZE-- >0)  {
   value =(signed char *)samples;

   f_write = write(f_open, value, size);  
  }

And now I can print data form sound card.

But I don't know why, and how it works...  I can only guess. 

Best wishes
Marek Michalak

2009/8/31 Marek Michalak <michalak.marek@xxxxxxxxx>

Hello!

I write a program that capture the sound and when the buffor of sound card is full send this by UDP to server. Then server will be calculate the FFT on this. So I need the samples. So my record_buffor function in  capture program:

static void record_buffor(const snd_pcm_channel_area_t *areas, snd_pcm_uframes_t offset,int count, double *_phase)
[...]
            unsigned char *samples[channels];
[...]
            f_write = write(f_open, *(samples), PERIOD_SIZE);      // save to the local disk     
            LiczbaBajtow=sendto( Deskryptor, *(samples), PERIOD_SIZE, 0, (struct sockaddr *)&AdresSerwera, sizeof(AdresSerwera));   //send to server
            while (PERIOD_SIZE-- >0)   {
              samples[chn] += steps[chn];
             }
            
I also try to save the file to local disk in this way:
unsigned char *tmp;
size = 2;
while (PERIOD_SIZE-- >0)  {
   tmp[byte] = *(samples[chn] + byte);
   f_write = write(f_open, tmp, size); 
  }
But I have value something like this ............^.^.^............^.^.^.^.^....... 

If I use fprintf (f_open, "%u",tmp[byte])
I have only "0.0.0.0.0.0."

So I need the key how open convert this *(samples) to anything that I can work with it. Could You help me?

Best wishes
Mark





Pozdrawiam
Marek Michalak

2009/8/31 Bill Unruh <unruh@xxxxxxxxxxxxxx>

On Mon, 31 Aug 2009, Marek Michalak wrote:

Hello!

I change the pcm.c program from alsa-lib/test, and capture the sound by
asynchronic function with mmap. But when I edit recorded file I've got only
dots like: ..................

Sound files are not text files. What are you using to try to edit the file?

When I open the file in aplay I have capture sound. How converts this 'dots'
to normal value that I can use in my program?

What program?

Best wishes
Marek Michalak

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