I am trying to learn audio recording, so I compiled The following code that I found online , but for some reason I cannot open /dev/dsp
. I tried killing pulseaudio, but it re-opens as soon as I killall
it. I really don't know what I am doing; I've been struggling for the latter part of the week. Please help.
I also tried chmod o+rw /dev/dsp
/*
* parrot.c
* Program to illustrate /dev/dsp device
* Records several seconds of sound, then echoes it back.
* Runs until Control-C is pressed.
*/
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <stdlib.h>
#include <stdio.h>
#include <linux/soundcard.h>
#define LENGTH 3 /* how many seconds of speech to store */
#define RATE 8000 /* the sampling rate */
#define SIZE 8 /* sample size: 8 or 16 bits */
#define CHANNELS 1 /* 1 = mono 2 = stereo */
/* this buffer holds the digitized audio */
unsigned char buf[LENGTH*RATE*SIZE*CHANNELS/8];
int main()
{
int fd; /* sound device file descriptor */
int arg; /* argument for ioctl calls */
int status; /* return status of system calls */
/* open sound device */
fd = open("/dev/dsp", O_RDWR);
if (fd < 0) {
perror("open of /dev/dsp failed");
exit(1);
}
/* set sampling parameters */
arg = SIZE; /* sample size */
status = ioctl(fd, SOUND_PCM_WRITE_BITS, &arg);
if (status == -1)
perror("SOUND_PCM_WRITE_BITS ioctl failed");
if (arg != SIZE)
perror("unable to set sample size");
arg = CHANNELS; /* mono or stereo */
status = ioctl(fd, SOUND_PCM_WRITE_CHANNELS, &arg);
if (status == -1)
perror("SOUND_PCM_WRITE_CHANNELS ioctl failed");
if (arg != CHANNELS)
perror("unable to set number of channels");
arg = RATE; /* sampling rate */
status = ioctl(fd, SOUND_PCM_WRITE_RATE, &arg);
if (status == -1)
perror("SOUND_PCM_WRITE_WRITE ioctl failed");
while (1) { /* loop until Control-C */
printf("Say something:\n");
status = read(fd, buf, sizeof(buf)); /* record some sound */
if (status != sizeof(buf))
perror("read wrong number of bytes");
printf("You said:\n");
status = write(fd, buf, sizeof(buf)); /* play it back */
if (status != sizeof(buf))
perror("wrote wrong number of bytes");
/* wait for playback to complete before recording again */
status = ioctl(fd, SOUND_PCM_SYNC, 0);
if (status == -1)
perror("SOUND_PCM_SYNC ioctl failed");
}
}
See, /dev/dsp was used on older versions of ubuntu linux. It's no longer available in newer versions of ubuntu. I think it was gone with 10.04. Things changed from 10.10.
From one of the websites:
10.10 Maverick finally disabled the very old OSS drivers (which provided /dev/dsp, so the padsp wrapper is the easiest way to handle if it you can't select ALSA or PulseAudio directly.
See this http://manpages.ubuntu.com/manpages/hardy/man1/padsp.1.html
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