Ubuntu 12.04下PulseAudio的安装以及API使用


一、Ubuntu 12.04下安装音频库客户端软件libpulse-dev

Package libpulse-dev：PulseAudio client development headers and libraries

使用如下命令：

sudo apt-get install libpulse-dev

安装时会提示依赖于下面这几个软件，一并安装即可：

libavahi-client-dev libavahi-common-dev libpulse-mainloop-glib0 libpulse0

这个也可以上packages.ubuntu.com官方网址查询libpulse-dev软件的依赖关系，相关链接如下：

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

如下图所示：

二、pulseaudio库的使用（同步simple API）

pulseaudio官网有关于pulseaudio的API doxygen使用手册，网址如下：

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

1、播音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, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received 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,
.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 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、录音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, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received 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,
.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、编译含有pulseaudio库的时候，需要添加pulseaudio的动态链接库-libpulse等，
 
(可以在/usr/lib/i386-linux-gnu/目录下找到pulse的动态库
 
/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)

例如：
 
 gcc -o pacat-simple pacat-simple.c -lpulse -lpulsecommon-1.1 -lpulse-simple

三、ALSA音频库

ALSA全称为：Advanced Linux Sound Architecture
 

一个网址为：http://www.alsa-project.org/main/index.php/Main_Page

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