mdw@git.distorted.org.uk Git - disorder/blob - lib/uaudio.h

   1 /*
   2  * This file is part of DisOrder.
   3  * Copyright (C) 2009 Richard Kettlewell
   4  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, either version 3 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 /** @file lib/uaudio.h
  20  * @brief Uniform audio interface
  21  */
  22
  23 #ifndef UAUDIO_H
  24 #define UAUDIO_H
  25
  26 /** @brief Callback to get audio data
  27  * @param buffer Where to put audio data
  28  * @param max_samples How many samples to supply
  29  * @param userdata As passed to uaudio_open()
  30  * @return Number of samples filled
  31  *
  32  * One sample is a single 16-bit signed value.
  33  */
  34 typedef size_t uaudio_callback(int16_t *buffer,
  35                                size_t max_samples,
  36                                void *userdata);
  37
  38 /** @brief Audio API definition */
  39 struct uaudio {
  40   /** @brief Name of this API */
  41   const char *name;
  42
  43   /** @brief List of options, terminated by NULL */
  44   const char *const *options;
  45
  46   /** @brief Do slow setup
  47    * @param ua Handle returned by uaudio_open()
  48    * @param callback Called for audio data
  49    * @param userdata Passed to @p callback
  50    *
  51    * This does resource-intensive setup for the output device.
  52    *
  53    * For instance it might open mixable audio devices or network sockets.  It
  54    * will create any background thread required.  However, it must not exclude
  55    * other processes from outputting sound.
  56    */
  57   void (*start)(uaudio_callback *callback,
  58                 void *userdata);
  59
  60   /** @brief Tear down
  61    * @param ua Handle returned by uaudio_open()
  62    *
  63    * This undoes the effect of @c start.
  64    */
  65   void (*stop)(void);
  66
  67   /** @brief Enable output
  68    *
  69    * A background thread will start calling @c callback as set by @c
  70    * start and playing the audio data received from it.
  71    */
  72   void (*activate)(void);
  73
  74   /** @brief Disable output
  75    *
  76    * The background thread will stop calling @c callback.
  77    */
  78   void (*deactivate)(void);
  79
  80 };
  81
  82 void uaudio_set(const char *name, const char *value);
  83 const char *uaudio_get(const char *name);
  84
  85 #if HAVE_COREAUDIO_AUDIOHARDWARE_H
  86 extern const struct uaudio uaudio_coreaudio;
  87 #endif
  88
  89 #if HAVE_ALSA_ASOUNDLIB_H
  90 extern const struct uaudio uaudio_alsa;
  91 #endif
  92
  93 #if HAVE_SYS_SOUNDCARD_H || EMPEG_HOST
  94 extern const struct uaudio uaudio_oss;
  95 #endif
  96
  97 extern const struct uaudio uaudio_rtp;
  98
  99 extern const struct uaudio *uaudio_apis[];
 100
 101 #endif /* UAUDIO_H */
 102
 103 /*
 104 Local Variables:
 105 c-basic-offset:2
 106 comment-column:40
 107 fill-column:79
 108 indent-tabs-mode:nil
 109 End:
 110 */