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 extern int uaudio_rate;
  27 extern int uaudio_bits;
  28 extern int uaudio_channels;
  29 extern int uaudio_signed;
  30 extern size_t uaudio_sample_size;
  31
  32 /** @brief Callback to get audio data
  33  * @param buffer Where to put audio data
  34  * @param max_samples How many samples to supply
  35  * @param userdata As passed to uaudio_open()
  36  * @return Number of samples filled
  37  */
  38 typedef size_t uaudio_callback(void *buffer,
  39                                size_t max_samples,
  40                                void *userdata);
  41
  42 /** @brief Callback to play audio data
  43  * @param buffer Pointer to audio buffer
  44  * @param samples Number of samples to play
  45  * @return Number of samples played
  46  *
  47  * Used with uaudio_thread_start() etc.
  48  */
  49 typedef size_t uaudio_playcallback(void *buffer, size_t samples);
  50
  51 /** @brief Audio API definition */
  52 struct uaudio {
  53   /** @brief Name of this API */
  54   const char *name;
  55
  56   /** @brief List of options, terminated by NULL */
  57   const char *const *options;
  58
  59   /** @brief Do slow setup
  60    * @param ua Handle returned by uaudio_open()
  61    * @param callback Called for audio data
  62    * @param userdata Passed to @p callback
  63    *
  64    * This does resource-intensive setup for the output device.
  65    *
  66    * For instance it might open mixable audio devices or network sockets.  It
  67    * will create any background thread required.  However, it must not exclude
  68    * other processes from outputting sound.
  69    */
  70   void (*start)(uaudio_callback *callback,
  71                 void *userdata);
  72
  73   /** @brief Tear down
  74    * @param ua Handle returned by uaudio_open()
  75    *
  76    * This undoes the effect of @c start.
  77    */
  78   void (*stop)(void);
  79
  80   /** @brief Enable output
  81    *
  82    * A background thread will start calling @c callback as set by @c
  83    * start and playing the audio data received from it.
  84    */
  85   void (*activate)(void);
  86
  87   /** @brief Disable output
  88    *
  89    * The background thread will stop calling @c callback.
  90    */
  91   void (*deactivate)(void);
  92
  93   /** @brief Open mixer device */
  94   void (*open_mixer)(void);
  95
  96   /** @brief Closer mixer device */
  97   void (*close_mixer)(void);
  98
  99   /** @brief Get volume
 100    * @param left Where to put the left-channel value
 101    * @param right Where to put the right-channel value
 102    *
 103    * 0 is silent and 100 is maximum volume.
 104    */
 105   void (*get_volume)(int *left, int *right);
 106
 107   /** @brief Set volume
 108    * @param left Pointer to left-channel value (updated)
 109    * @param right Pointer to right-channel value (updated)
 110    *
 111    * The values are updated with those actually set by the underlying system
 112    * call.
 113    *
 114    * 0 is silent and 100 is maximum volume.
 115    */
 116   void (*set_volume)(int *left, int *right);
 117
 118   /** @brief Set configuration */
 119   void (*configure)(void);
 120
 121 };
 122
 123 void uaudio_set_format(int rate, int channels, int samplesize, int signed_);
 124 void uaudio_set(const char *name, const char *value);
 125 char *uaudio_get(const char *name, const char *default_value);
 126 void uaudio_thread_start(uaudio_callback *callback,
 127                          void *userdata,
 128                          uaudio_playcallback *playcallback,
 129                          size_t min,
 130                          size_t max);
 131 void uaudio_thread_stop(void);
 132 void uaudio_thread_activate(void);
 133 void uaudio_thread_deactivate(void);
 134 void uaudio_schedule_synchronize(void);
 135 void uaudio_schedule_update(size_t written_samples);
 136 void uaudio_schedule_init(void);
 137 const struct uaudio *uaudio_find(const char *name);
 138
 139 extern uint64_t uaudio_schedule_timestamp;
 140 extern int uaudio_schedule_reactivated;
 141
 142 #if HAVE_COREAUDIO_AUDIOHARDWARE_H
 143 extern const struct uaudio uaudio_coreaudio;
 144 #endif
 145
 146 #if HAVE_ALSA_ASOUNDLIB_H
 147 extern const struct uaudio uaudio_alsa;
 148 #endif
 149
 150 #if HAVE_SYS_SOUNDCARD_H || EMPEG_HOST
 151 extern const struct uaudio uaudio_oss;
 152 #endif
 153
 154 extern const struct uaudio uaudio_rtp;
 155
 156 extern const struct uaudio uaudio_command;
 157
 158 extern const struct uaudio *const uaudio_apis[];
 159
 160 #endif /* UAUDIO_H */
 161
 162 /*
 163 Local Variables:
 164 c-basic-offset:2
 165 comment-column:40
 166 fill-column:79
 167 indent-tabs-mode:nil
 168 End:
 169 */