Rich,
On Mon, 4 Jun 2001, Rich Payne <[EMAIL PROTECTED]> wrote:
>
> Well, it works OK here using XMMS instead of real, I just setup xmms to
> play and did a "rec test.wav" and sure enough the test.wav contained the
> audio, I don't have realplayer on this machine...but in theory :)
Hey that is pretty neat!
It doesn't seem to work for me here (the rec fails due to device busy).
I think this is because I am not running Enlightenment Sound Daemon (esd).
You are running esd, right?
Below is a hack I wrote that interposes on the open(2), close(2), and
write(2) system calls and tees the /dev/dsp output to a regular file.
It at least works with capturing RealPlayer output on my system.
sox(1) can then be used to replay or reformat the raw output.
I enclose it below since this LD_PRELOAD method is a general and rather
useful trick that can be used to interpose and "tweak" *any* function
call. Many applications ;-)
Karl
----------------------------------------------------------------------------
/*
* open.c: interpose open() calls to /dev/dsp and tee the resulting dsp
* write()'s to a regular file.
*
* compile: cc -shared -o open.so open.c
*
* run: LD_PRELOAD=./open.so <cmd> <args>
* (e.g. <cmd> is "realplay")
*
* playback: sox -r 20000 -w -s -t raw /tmp/dsp.out.2 -t ossdsp /dev/dsp
*
* The raw output file, "/tmp/dsp.out.2" here, is noted on stderr.
* The sampling rate, "20000" here, is noted on stderr, or otherwise
* you can attempt trial & error to guess the sampling rate.
* Use -c 2 for stereo. Use sox to convert to different formats.
* See sox(1) for more info.
*/
#include <stdio.h>
#include <fcntlbits.h>
#include <sys/soundcard.h>
#define SOX "playback: sox -r %d -w -s -t raw %s -t ossdsp /dev/dsp\n"
extern int __open(const char *pathname, int flags, unsigned short mode);
extern int __close (int fd);
extern ssize_t __write (int fd, __const __ptr_t buf, size_t n);
int tee_fd, dsp_fd, dsp_written, cnt = 0;
char outfile[100];
int open(const char *pathname, int flags, unsigned short mode) {
int fd, fd2;
fd = __open(pathname, flags, mode);
if (!strcmp("/dev/dsp", pathname) && fd > 0 ) {
sprintf(outfile, "/tmp/dsp.out.%d", ++cnt);
dsp_written = 0;
dsp_fd = 0;
tee_fd = 0;
fd2 = __open(outfile, O_WRONLY|O_CREAT|O_TRUNC, 00644);
if ( fd2 > 0 ) {
dsp_fd = fd;
tee_fd = fd2;
fprintf(stderr,"teeing audio dsp_fd %d to fd %d "
"aka %s ...\n", dsp_fd, fd2, outfile);
}
}
return fd;
}
int close(int fd) {
if ( fd == dsp_fd && tee_fd > 1 ) {
__close(tee_fd);
fprintf(stderr, "closing tee_fd: %d aka %s\n", tee_fd, outfile);
tee_fd = 0;
}
return(__close(fd));
}
ssize_t write (int fd, __const __ptr_t buf, size_t n) {
if ( fd == dsp_fd && tee_fd > 1 ) {
if ( ! dsp_written ) {
int speed = 0;
if ( ioctl(fd, SNDCTL_DSP_SPEED, &speed) == 0 ) {
fprintf(stderr, "speed for dsp_fd %d is: %d\n",
fd, speed);
fprintf(stderr, SOX, speed, outfile);
}
dsp_written = 1;
}
__write(tee_fd, buf, n);
}
return(__write(fd, buf, n));
}
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