5 Feb
2004
5 Feb
'04
9:15 p.m.
I wanted to do a simple task. I just want to
playback a raw file (16BIT,
stereo, 44100Hz). So I used the alsa_pcm_seq-howto and compied a bit of code
from it. But it doesn't work. I get the device read for playing and I get
sound... But it's just noise. I'm frustrated. I tried to copy the relevant
part out of the aplay-sources, but they have so many config stuff... Can
anyone help me with a bit of code or a place where I should just get some
code
for only:
Moin
1. opening a raw-file
Use functions
open()
read()
close()
or
fopen()
fread()
fclose()
Examples deutsch
http://pronix.de/modules/C/openbook/
http://pronix.de/modules/C/openbook/c_programmierung_19_5.php#25
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#ifdef __unix__
#include <unistd.h>
#elif __MSDOS__ || __WIN32__ || _MSC_VER
#include <io.h>
#endif
int main()
{
int fh;
if((fh=open("adress.txt",O_RDWR|O_CREAT|O_TRUNC))==-1)
{
printf("Fehler bei open()…\n");
exit (0);
}
close(fh);
return 0;
}
2. setting up the alsa-driver for playbakc
sorry This is for oss
int audio_fd;
/*----*/void open_sound_device(void){
/*----*/ int format; int stereo = 1; int rate = 44100;
/*----*/ if ((audio_fd = open("/dev/dsp", O_WRONLY , 0)) == -1)
/*----*/ {
/*----*/ perror("/dev/dsp");
/*----*/ exit(1);
/*----*/ }
/*----*/ format = AFMT_S16_LE;
/*----*/ if (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &format)==-1)
/*----*/ {
/*----*/ perror("SNDCTL_DSP_SETFMT"); exit(1);
/*----*/ }
/*----*/ if (format != AFMT_S16_LE)
/*----*/ { fprintf(stderr,"Output format not set correctly"); }
/*----*/ if (ioctl(audio_fd, SNDCTL_DSP_STEREO, &stereo)==-1)
/*----*/ {
/*----*/ perror("SNDCTL_DSP_STEREO"); exit(1);
/*----*/ }
/*----*/ if (ioctl(audio_fd, SNDCTL_DSP_SPEED, &rate)==-1)
/*----*/ { /* Fatal error */
/*----*/ perror("SNDCTL_DSP_SPEED"); exit(1);
/*----*/ }
/*----*/} // o s d //
/*----*/void close_sound_device(void)
/*----*/{
/*----*/ close(audio_fd);
/*----*/}
3. Read data from the file and write it to the soundcard.
status = read(fdi, adat , sizeof( adat )); /* record some sound */
///// wird etwas gemacht mit adat z.b. audio_buffer[i] = adat[i];
write(audio_fd , audio_buffer , sizeof( audio_buffer ) );
Ralfs K