Installation and API use of PulseAudio in Ubuntu 12.04

1. Install the audio library client software libpulse-dev in Ubuntu 12.04

Package libpulse-dev: PulseAudio client development headers and libraries

Run the following command:

Sudo apt-get install libpulse-dev

During installation, you will be prompted to install these software together:

Libpulse0 libavahi-client-dev libavahi-common-dev libpulse-mainloop-glib0

You can also query the libpulse-dev dependency on the official packages.ubuntu.com website. The related links are as follows:

Http://packages.ubuntu.com/raring/libpulse-dev

As shown in:

Ii. Use of pulseaudio Library (synchronous simple API)

The official pulseaudio website has a user manual for the pulseaudio API doxygen. The URL is as follows:

Http://freedesktop.org/software/pulseaudio/doxygen/

1. Broadcasting sample

A simple playback tool using the simple API

// <Span style = "font-size: 14px;"> pacat-simple.c </span>
/***
This file is part of PulseAudio.
PulseAudio is free software; you can redistribute it and/or modify
It under the terms of the GNU Lesser General Public License as published
By the Free Software Foundation; either version 2.1 of the License,
Or (at your option) any later version.
PulseAudio is distributed in the hope that it will be useful,
Without any warranty; without even the implied warranty
MERCHANTABILITY or fitness for a particle PURPOSE. See the GNU
General Public License for more details.
You shoshould have your ed a copy of the GNU Lesser General Public License
Along with PulseAudio; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA.
***/
# Ifdef HAVE_CONFIG_H
# Include <config. h>
# Endif
# Include <stdio. h>
# Include <unistd. h>
# Include <string. h>
# Include <errno. h>
# Include <fcntl. h>
# Include <pulse/simple. h>
# Include <pulse/error. h>
# Define BUFSIZE 1024
Int main (int argc, char * argv []) {
/* The Sample format to use */
Static const pa_sample_spec ss = {
. Format = PA_SAMPLE_S16LE,
. Speed = 44100,
. Channels = 2
};
Pa_simple * s = NULL;
Int ret = 1;
Int error;
/* Replace STDIN with the specified file if needed */
If (argc> 1 ){
Int fd;
If (fd = open (argv [1], O_RDONLY) <0 ){
Fprintf (stderr, _ FILE _ ": open () failed: % s \ n", strerror (errno ));
Goto finish;
}
If (dup2 (fd, STDIN_FILENO) <0 ){
Fprintf (stderr, _ FILE _ ": dup2 () failed: % s \ n", strerror (errno ));
Goto finish;
}
Close (fd );
}
/* Create a new playback stream */
If (! (S = pa_simple_new (NULL, argv [0], PA_STREAM_PLAYBACK, NULL, "playback", & ss, NULL, NULL, & error ))){
Fprintf (stderr, _ FILE _ ": pa_simple_new () failed: % s \ n", pa_strerror (error ));
Goto finish;
}
For (;;){
Uint8_t buf [BUFSIZE];
Ssize_t r;
# If 0
Pa_usec_t latency;
If (latency = pa_simple_get_latency (s, & error) = (pa_usec_t)-1 ){
Fprintf (stderr, _ FILE _ ": pa_simple_get_latency () failed: % s \ n", pa_strerror (error ));
Goto finish;
}
Fprintf (stderr, "% 0.0f usec \ r", (float) latency );
# Endif
/* Read some data ...*/
If (r = read (STDIN_FILENO, buf, sizeof (buf) <= 0 ){
If (r = 0)/* EOF */
Break;
Fprintf (stderr, _ FILE _ ": read () failed: % s \ n", strerror (errno ));
Goto finish;
}
/*... And play it */
If (pa_simple_write (s, buf, (size_t) r, & error) <0 ){
Fprintf (stderr, _ FILE _ ": pa_simple_write () failed: % s \ n", pa_strerror (error ));
Goto finish;
}
}
/* Make sure that every single sample was played */
If (pa_simple_drain (s, & error) <0 ){
Fprintf (stderr, _ FILE _ ": pa_simple_drain () failed: % s \ n", pa_strerror (error ));
Goto finish;
}
Ret = 0;
Finish:
If (s)
Pa_simple_free (s );
Return ret;
}

2. Recording sample

A simple recording tool using the simple API

// Parec-simple.c
/***
This file is part of PulseAudio.
PulseAudio is free software; you can redistribute it and/or modify
It under the terms of the GNU Lesser General Public License as published
By the Free Software Foundation; either version 2.1 of the License,
Or (at your option) any later version.
PulseAudio is distributed in the hope that it will be useful,
Without any warranty; without even the implied warranty
MERCHANTABILITY or fitness for a particle PURPOSE. See the GNU
General Public License for more details.
You shoshould have your ed a copy of the GNU Lesser General Public License
Along with PulseAudio; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA.
***/
# Ifdef HAVE_CONFIG_H
# Include <config. h>
# Endif
# Include <stdio. h>
# Include <unistd. h>
# Include <string. h>
# Include <errno. h>
# Include <pulse/simple. h>
# Include <pulse/error. h>
# Define BUFSIZE 1024
/* A simple routine calling UNIX write () in a loop */
Static ssize_t loop_write (int fd, const void * data, size_t size ){
Ssize_t ret = 0;
While (size> 0 ){
Ssize_t r;
If (r = write (fd, data, size) <0)
Return r;
If (r = 0)
Break;
Ret + = r;
Data = (const uint8_t *) data + r;
Size-= (size_t) r;
}
Return ret;
}
Int main (int argc, char * argv []) {
/* The sample type to use */
Static const pa_sample_spec ss = {
. Format = PA_SAMPLE_S16LE,
. Speed = 44100,
. Channels = 2
};
Pa_simple * s = NULL;
Int ret = 1;
Int error;
/* Create the recording stream */
If (! (S = pa_simple_new (NULL, argv [0], PA_STREAM_RECORD, NULL, "record", & ss, NULL, NULL, & error ))){
Fprintf (stderr, _ FILE _ ": pa_simple_new () failed: % s \ n", pa_strerror (error ));
Goto finish;
}
For (;;){
Uint8_t buf [BUFSIZE];
/* Record some data ...*/
If (pa_simple_read (s, buf, sizeof (buf), & error) <0 ){
Fprintf (stderr, _ FILE _ ": pa_simple_read () failed: % s \ n", pa_strerror (error ));
Goto finish;
}
/* And write it to STDOUT */
If (loop_write (STDOUT_FILENO, buf, sizeof (buf ))! = Sizeof (buf )){
Fprintf (stderr, _ FILE _ ": write () failed: % s \ n", strerror (errno ));
Goto finish;
}
}
Ret = 0;
Finish:
If (s)
Pa_simple_free (s );
Return ret;
}

3. When compiling a pulseaudio library, you must add the dynamic link library libpulse of the pulseaudio library,
 
(You can find the pulse dynamic library under the/usr/lib/i386-linux-gnu/directory
 
/Usr/lib/i386-linux-gnu/libpulsecommon-1.1.so
/Usr/lib/i386-linux-gnu/libpulsedsp. so
/Usr/lib/i386-linux-gnu/libpulse-mainloop-glib.so
/Usr/lib/i386-linux-gnu/libpulse-mainloop-glib.so.0
/Usr/lib/i386-linux-gnu/libpulse-mainloop-glib.so.0.0.4
/Usr/lib/i386-linux-gnu/libpulse-simple.so
/Usr/lib/i386-linux-gnu/libpulse-simple.so.0
/Usr/lib/i386-linux-gnu/libpulse-simple.so.0.0.3
/Usr/lib/i386-linux-gnu/libpulse. so
/Usr/lib/i386-linux-gnu/libpulse. so.0
/Usr/lib/i386-linux-gnu/libpulse. so.0.13.5)

For example:
 
Gcc-o pacat-simple pacat-simple.c-lpulse-lpulsecommon-1.1-lpulse-simple

Iii. ALSA audio library

ALSA is fully called: Advanced Linux Sound Architecture
 

A Web site: http://www.alsa-project.org/main/index.php/Main_Page