audio_ao.c

   1 /*
   2  * libao output driver. This file is part of Shairport.
   3  * Copyright (c) James Laird 2013
   4  * Copyright (c) Mike Brady 2014 -- 2022
   5  * All rights reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person
   8  * obtaining a copy of this software and associated documentation
   9  * files (the "Software"), to deal in the Software without
  10  * restriction, including without limitation the rights to use,
  11  * copy, modify, merge, publish, distribute, sublicense, and/or
  12  * sell copies of the Software, and to permit persons to whom the
  13  * Software is furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be
  16  * included in all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  19  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  20  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  21  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  22  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  23  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  24  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  25  * OTHER DEALINGS IN THE SOFTWARE.
  26  */
  27
  28 #include "audio.h"
  29 #include "common.h"
  30 #include <ao/ao.h>
  31 #include <memory.h>
  32 #include <stdio.h>
  33 #include <unistd.h>
  34
  35 ao_device *dev = NULL;
  36 ao_option *ao_opts = NULL;
  37 ao_sample_format fmt;
  38 int driver = 0;
  39
  40 static void help(void) {
  41   printf("    -d driver           set the output driver\n"
  42          "    -o name=value       set an arbitrary ao option\n"
  43          "    -i id               shorthand for -o id=<id>\n"
  44          "    -n name             shorthand for -o dev=<name> -o dsp=<name>\n");
  45   // get a list of drivers available
  46   ao_initialize();
  47   int defaultDriver = ao_default_driver_id();
  48   if (defaultDriver == -1) {
  49     printf("    No usable drivers available.\n");
  50   } else {
  51     ao_info *defaultDriverInfo = ao_driver_info(defaultDriver);
  52     int driver_count;
  53     ao_info **driver_list = ao_driver_info_list(&driver_count);
  54     int i = 0;
  55     if (driver_count == 0) {
  56       printf("    Driver list unavailable.\n");
  57     } else {
  58       printf("    Drivers:\n");
  59       for (i = 0; i < driver_count; i++) {
  60         ao_info *the_driver = driver_list[i];
  61         if (strcmp(the_driver->short_name, defaultDriverInfo->short_name) == 0)
  62           printf("        \"%s\" (default)\n", the_driver->short_name);
  63         else
  64           printf("        \"%s\"\n", the_driver->short_name);
  65       }
  66     }
  67   }
  68   ao_shutdown();
  69 }
  70
  71 static int init(int argc, char **argv) {
  72   ao_initialize();
  73   driver = ao_default_driver_id();
  74   if (driver == -1) {
  75     warn("libao can not find a usable driver!");
  76   } else {
  77
  78     // set up default values first
  79
  80     config.audio_backend_buffer_desired_length = 1.0;
  81     config.audio_backend_latency_offset = 0;
  82
  83     // get settings from settings file first, allow them to be overridden by
  84     // command line options
  85
  86     // do the "general" audio  options. Note, these options are in the "general" stanza!
  87     parse_general_audio_options();
  88
  89     optind = 1; // optind=0 is equivalent to optind=1 plus special behaviour
  90     argv--;     // so we shift the arguments to satisfy getopt()
  91     argc++;
  92
  93     // some platforms apparently require optreset = 1; - which?
  94     int opt;
  95     char *mid;
  96     while ((opt = getopt(argc, argv, "d:i:n:o:")) > 0) {
  97       switch (opt) {
  98       case 'd':
  99         driver = ao_driver_id(optarg);
 100         if (driver < 0)
 101           die("could not find ao driver %s", optarg);
 102         break;
 103       case 'i':
 104         ao_append_option(&ao_opts, "id", optarg);
 105         break;
 106       case 'n':
 107         ao_append_option(&ao_opts, "dev", optarg);
 108         // Old libao versions (for example, 0.8.8) only support
 109         // "dsp" instead of "dev".
 110         ao_append_option(&ao_opts, "dsp", optarg);
 111         break;
 112       case 'o':
 113         mid = strchr(optarg, '=');
 114         if (!mid)
 115           die("Expected an = in audio option %s", optarg);
 116         *mid = 0;
 117         ao_append_option(&ao_opts, optarg, mid + 1);
 118         break;
 119       default:
 120         help();
 121         die("Invalid audio option -%c specified", opt);
 122       }
 123     }
 124
 125     if (optind < argc)
 126       die("Invalid audio argument: %s", argv[optind]);
 127
 128     memset(&fmt, 0, sizeof(fmt));
 129
 130     fmt.bits = 16;
 131     fmt.rate = 44100;
 132     fmt.channels = 2;
 133     fmt.byte_format = AO_FMT_NATIVE;
 134     fmt.matrix = strdup("L,R");
 135   }
 136   return 0;
 137 }
 138
 139 static void deinit(void) {
 140   if (dev != NULL)
 141     ao_close(dev);
 142   dev = NULL;
 143   ao_shutdown();
 144 }
 145
 146 static void start(__attribute__((unused)) int sample_rate,
 147                   __attribute__((unused)) int sample_format) {
 148   // debug(1,"libao start");
 149 }
 150
 151 static int play(void *buf, int samples, __attribute__((unused)) int sample_type,
 152                 __attribute__((unused)) uint32_t timestamp,
 153                 __attribute__((unused)) uint64_t playtime) {
 154   int response = 0;
 155   int oldState;
 156   pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
 157   if (driver != -1) {
 158     if (dev == NULL)
 159       dev = ao_open_live(driver, &fmt, ao_opts);
 160     if (dev != NULL)
 161       response = ao_play(dev, buf, samples * 4);
 162   }
 163   pthread_setcancelstate(oldState, NULL);
 164   return response;
 165 }
 166
 167 static void stop(void) {
 168   // debug(1,"libao stop");
 169   if (dev != NULL) {
 170     ao_close(dev);
 171     dev = NULL;
 172   }
 173 }
 174
 175 audio_output audio_ao = {.name = "ao",
 176                          .help = &help,
 177                          .init = &init,
 178                          .deinit = &deinit,
 179                          .prepare = NULL,
 180                          .start = &start,
 181                          .stop = &stop,
 182                          .is_running = NULL,
 183                          .flush = NULL,
 184                          .delay = NULL,
 185                          .stats = NULL,
 186                          .play = &play,
 187                          .volume = NULL,
 188                          .parameters = NULL,
 189                          .mute = NULL};