Installation and API use of pulseaudio under ubuntu12.04

1. Install the audio library client software libpulse-Dev in ubuntu12.04

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

//pacat-simple.c/***This file is part of PulseAudio.PulseAudio is free software; you can redistribute it and/or modifyit under the terms of the GNU Lesser General Public License as publishedby 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, butWITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNUGeneral Public License for more details.You should have received a copy of the GNU Lesser General Public Licensealong with PulseAudio; if not, write to the Free SoftwareFoundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307USA.***/#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 1024int main(int argc, char*argv[]) {/* The Sample format to use */static const pa_sample_spec ss = {.format = PA_SAMPLE_S16LE,.rate = 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 0pa_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 modifyit under the terms of the GNU Lesser General Public License as publishedby 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, butWITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNUGeneral Public License for more details.You should have received a copy of the GNU Lesser General Public Licensealong with PulseAudio; if not, write to the Free SoftwareFoundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307USA.***/#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,.rate = 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 and running the pulseaudio library, you need to add the dynamic link library of pulseaudio.-Libpulse, etc,

(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, a pacat-simple.c program:

(1) The compilation command is as follows:

Gcc-O pacat-simple pacat-simple.c-lpulse-lpulsecommon-1.1-lpulse-simple
(2) run the pacat-simple executable program generated in the previous step.

./Pacat-simple .wav

(Note: There is a command line parameter, which is the audio file name. You can search online for an audio file in WAV format and put it in the current directory .)

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