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Zaurus audio development howto:
by L.J. Potter
To get brief audio device info: run this command from the console:
# cat /dev/sndstat
The VERY easiest way to play sound is to use use cat command such as this:
# cat myNewSound >/dev/dsp
or in a program, use system()
system( "cat myNewSound >/dev/dsp");
The VERY easiest way to record sound is to use use cat command such as this:
# cat /dev/dsp1 >myNewSound
or in a program, use system()
system( "cat /dev/dsp1 >myNewSound");
This is not the most elegant way to do this.
The next easiest way to play audio is to use QSound:
The benefits are that you should be able to play more than one sound at a
time.
*NOTE: there is no QSound::record()
#include <qsound.h>
#include <qpe/resource.h>
QSound::play( Resource::findSound("ohdear") );
* NOTE: There is a bug on the Zaurus with QSound not being able to play sounds
shorter than about 8k.
or if you can use Qtopia's Sound class to loop sounds:
(there's no docs, so grab the qtopia cvs at sourceforge
and look in the source)
#include <qpe/sound.h>
#include <qpe/resource.h>
Sound::soundAlarm();
or something like:
Sound mySound( Resource::findSound("ohdear") );
mySound.playLoop();
mySound.stop();
* NOTE: There is a bug on the Zaurus with QSound not being able to play sounds
shorter than about 8k.
Using oss with the Zaurus:
Playing sounds:
-----------------
#include <sys/ioctl.h>
#include <linux/soundcard.h>
int speed = 44100;
int channels = 2;
int format = AFMT_S16_LE; // or AFMT_U8, but has buggy
output on the Z
int dsp=0;
signed short soundBuffer[1024];
dsp = ::open("/dev/dsp", O_WRONLY);
if( dsp == -1) {
perror("open(\"/dev/dsp\")");
return;
}
// this is assuming you know what the format of the wav
file is.
// otherwise you'd have to read the header file first.
if( ioctl( dsp, SNDCTL_DSP_SETFMT , &format)==-1)
{
perror("ioctl(\"SNDCTL_DSP_SETFMT\")");
return -1;
}
if( ioctl( dsp, SNDCTL_DSP_CHANNELS , &channels)==-1)
{
perror("ioctl(\"SNDCTL_DSP_CHANNELS\")");
return -1;
}
if( ioctl( dsp, SNDCTL_DSP_SPEED , &speed)==-1)
{
perror("ioctl(\"SNDCTL_DSP_SPEED\")");
return -1;
}
QFile track( "/opt/QtPalmtop/sounds/somesound.wav" );
if( !track.open( IO_ReadOnly )) {
QMessageBox:message("Sounds","There was an error opening the wav file");
return -1;
}
int oldStyleFileHandle = track.handle();
int length;
while( !track.atEnd()) {
length = ::read( oldStyleFileHandle, soundBuffer, 1024
); //read from the file
::write( dsp, soundBuffer, length); //write to the device
}
::close (dsp);
track.close();
To record:
-----------
#include <sys/ioctl.h>
#include <linux/soundcard.h>
int speed = 22050;
int channels = 1;
// *NOTE* the Zaurus input is ONLY mono !!
int format = AFMT_S16_LE;
int dsp=0;
signed short soundBuffer[1024];
dsp = ::open("/dev/dsp1", O_RDONLY);
// *NOTE* the Zaurus has a nonstandard input
// so /dev/dsp1 must be opened when
// recording
if( dsp == -1) {
perror("open(\"/dev/dsp\")");
return;
}
// this is assuming you know what the format of the wav
file is.
// otherwise you'd have to read the header file first.
if( ioctl( dsp, SNDCTL_DSP_SETFMT , &format)==-1)
{
perror("ioctl(\"SNDCTL_DSP_SETFMT\")");
return -1;
}
if( ioctl( dsp, SNDCTL_DSP_CHANNELS , &channels)==-1)
{
perror("ioctl(\"SNDCTL_DSP_CHANNELS\")");
return -1;
}
if( ioctl( dsp, SNDCTL_DSP_SPEED , &speed)==-1)
{
perror("ioctl(\"SNDCTL_DSP_SPEED\")");
return -1;
}
QFile track( "/opt/QtPalmtop/sounds/myNewSound.wav" );
if( !track.open( IO_WriteOnly | IO_Truncate )) {
QMessageBox:message("Sounds","There was an error opening the wav file");
return -1;
}
int oldStyleFileHandle = track.handle();
int length;
while( 1) { // or some other way to stop this crazy
thing
length = ::read( dsp, soundBuffer, 1024 ); //read from
the file
::write( oldStyleFileHandle, soundBuffer, length);
//write to the device
}
::close (dsp);
track.close();
// to make a standard wav file, you would need to write
// a header before you start writing from the device, and then
// write to the header after you finish
For more information about programming OSS, visit:
http://www.opensound.com
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This page was last updated: May 21 2003 06:25:12.
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