Ubuntu18.04 PulseAudio實戰

1 前言

2 下載下傳編譯

具體建構過程參照官方文檔：https://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/Developer/PulseAudioFromGit/

2.1 下載下傳代碼

git clone git://anongit.freedesktop.org/pulseaudio/pulseaudio

2.2 編譯

編譯過程遇到太多錯誤了，見問題集，主要是依賴沒有安裝

meson build

ninja -C build

sudo ninja -C build install

sudo ldconfig

3 demo實踐

PulseAudio對外api非常簡單，基本就是和io操作一樣：read，write，open…

pa_simple_new：建立到伺服器的新連接配接。

pa_simple_read：從伺服器讀取一些資料。（阻塞）

pa_simple_write：向伺服器寫入一些資料。

pa_simple_free：關閉并釋放與伺服器的連接配接。

pa_simple_drain：等待守護程序播放所有已寫入的資料。

pa_simple_flush：重新整理播放或記錄緩沖區。

pa_simple_get_latency：傳回播放或記錄延遲。

下面是官方demo：

/***
  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, see <http://www.gnu.org/licenses/>.
***/
 
#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;
}

           

4 問題集

4.1 tdb庫缺失

問題描述

meson.build:595:2: ERROR: Dependency “tdb” not found, tried pkgconfig and cmake

解決方案：

下載下傳最新版本tdb編譯安裝。

下載下傳位址：https://www.samba.org/ftp/tdb/

tar -xvf tdb-1.4.5.tar.gz

cd tdb-1.4.5

./configure && make && make install

4.2 sndfile庫缺失

meson.build:653:0: ERROR: Dependency “sndfile” not found, tried pkgconfig and cmake

解決方案：

下載下傳最新版本tdb編譯安裝。

下載下傳位址：http://www.mega-nerd.com/libsndfile/

tar -xvf libsndfile-1.0.28.tar.gz

cd libsndfile-1.0.28

./configure && make && make install

4.3 xtst庫缺失

meson.build:686:2: ERROR: Dependency “xtst” not found, tried pkgconfig and cmake

解決方案：

sudo apt-get install libxtst-dev

4.4 check庫缺失

meson.build:792:0: ERROR: Dependency “check” not found, tried pkgconfig and cmake

解決方案：

apt-get install check