examples/alstream.c

   1 /*
   2  * OpenAL Audio Stream Example
   3  *
   4  * Copyright (c) 2011 by Chris Robinson <chris.kcat@gmail.com>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 /* This file contains a relatively simple streaming audio player. */
  26
  27 #include <string.h>
  28 #include <stdlib.h>
  29 #include <stdio.h>
  30 #include <signal.h>
  31 #include <assert.h>
  32
  33 #include "AL/al.h"
  34 #include "AL/alc.h"
  35 #include "AL/alext.h"
  36
  37 #include "common/alhelpers.h"
  38 #include "common/sdl_sound.h"
  39
  40
  41 static LPALBUFFERSAMPLESSOFT alBufferSamplesSOFT = wrap_BufferSamples;
  42 static LPALISBUFFERFORMATSUPPORTEDSOFT alIsBufferFormatSupportedSOFT;
  43
  44
  45 /* Define the number of buffers and buffer size (in milliseconds) to use. 4
  46  * buffers with 200ms each gives a nice per-chunk size, and lets the queue last
  47  * for almost one second. */
  48 #define NUM_BUFFERS 4
  49 #define BUFFER_TIME_MS 200
  50
  51 typedef struct StreamPlayer {
  52     /* These are the buffers and source to play out through OpenAL with */
  53     ALuint buffers[NUM_BUFFERS];
  54     ALuint source;
  55
  56     /* Handle for the audio file */
  57     FilePtr file;
  58
  59     /* The format of the output stream */
  60     ALenum format;
  61     ALenum channels;
  62     ALenum type;
  63     ALuint rate;
  64 } StreamPlayer;
  65
  66 static StreamPlayer *NewPlayer(void);
  67 static void DeletePlayer(StreamPlayer *player);
  68 static int OpenPlayerFile(StreamPlayer *player, const char *filename);
  69 static void ClosePlayerFile(StreamPlayer *player);
  70 static int StartPlayer(StreamPlayer *player);
  71 static int UpdatePlayer(StreamPlayer *player);
  72
  73 /* Creates a new player object, and allocates the needed OpenAL source and
  74  * buffer objects. Error checking is simplified for the purposes of this
  75  * example, and will cause an abort if needed. */
  76 static StreamPlayer *NewPlayer(void)
  77 {
  78     StreamPlayer *player;
  79
  80     player = malloc(sizeof(*player));
  81     assert(player != NULL);
  82
  83     memset(player, 0, sizeof(*player));
  84
  85     /* Generate the buffers and source */
  86     alGenBuffers(NUM_BUFFERS, player->buffers);
  87     assert(alGetError() == AL_NO_ERROR && "Could not create buffers");
  88
  89     alGenSources(1, &player->source);
  90     assert(alGetError() == AL_NO_ERROR && "Could not create source");
  91
  92     /* Set parameters so mono sources play out the front-center speaker and
  93      * won't distance attenuate. */
  94     alSource3i(player->source, AL_POSITION, 0, 0, -1);
  95     alSourcei(player->source, AL_SOURCE_RELATIVE, AL_TRUE);
  96     alSourcei(player->source, AL_ROLLOFF_FACTOR, 0);
  97     assert(alGetError() == AL_NO_ERROR && "Could not set source parameters");
  98
  99     return player;
 100 }
 101
 102 /* Destroys a player object, deleting the source and buffers. No error handling
 103  * since these calls shouldn't fail with a properly-made player object. */
 104 static void DeletePlayer(StreamPlayer *player)
 105 {
 106     ClosePlayerFile(player);
 107
 108     alDeleteSources(1, &player->source);
 109     alDeleteBuffers(NUM_BUFFERS, player->buffers);
 110     if(alGetError() != AL_NO_ERROR)
 111         fprintf(stderr, "Failed to delete object IDs\n");
 112
 113     memset(player, 0, sizeof(*player));
 114     free(player);
 115 }
 116
 117
 118 /* Opens the first audio stream of the named file. If a file is already open,
 119  * it will be closed first. */
 120 static int OpenPlayerFile(StreamPlayer *player, const char *filename)
 121 {
 122     ClosePlayerFile(player);
 123
 124     /* Open the file and get the first stream from it */
 125     player->file = openAudioFile(filename, BUFFER_TIME_MS);
 126     if(!player->file)
 127     {
 128         fprintf(stderr, "Could not open audio in %s\n", filename);
 129         goto error;
 130     }
 131
 132     /* Get the stream format, and figure out the OpenAL format */
 133     if(getAudioInfo(player->file, &player->rate, &player->channels, &player->type) != 0)
 134     {
 135         fprintf(stderr, "Error getting audio info for %s\n", filename);
 136         goto error;
 137     }
 138
 139     player->format = GetFormat(player->channels, player->type, alIsBufferFormatSupportedSOFT);
 140     if(player->format == 0)
 141     {
 142         fprintf(stderr, "Unsupported format (%s, %s) for %s\n",
 143                 ChannelsName(player->channels), TypeName(player->type),
 144                 filename);
 145         goto error;
 146     }
 147
 148     return 1;
 149
 150 error:
 151     closeAudioFile(player->file);
 152     player->file = NULL;
 153
 154     return 0;
 155 }
 156
 157 /* Closes the audio file stream */
 158 static void ClosePlayerFile(StreamPlayer *player)
 159 {
 160     closeAudioFile(player->file);
 161     player->file = NULL;
 162 }
 163
 164
 165 /* Prebuffers some audio from the file, and starts playing the source */
 166 static int StartPlayer(StreamPlayer *player)
 167 {
 168     size_t i;
 169
 170     /* Rewind the source position and clear the buffer queue */
 171     alSourceRewind(player->source);
 172     alSourcei(player->source, AL_BUFFER, 0);
 173
 174     /* Fill the buffer queue */
 175     for(i = 0;i < NUM_BUFFERS;i++)
 176     {
 177         uint8_t *data;
 178         size_t got;
 179
 180         /* Get some data to give it to the buffer */
 181         data = getAudioData(player->file, &got);
 182         if(!data) break;
 183
 184         alBufferSamplesSOFT(player->buffers[i], player->rate, player->format,
 185                             BytesToFrames(got, player->channels, player->type),
 186                             player->channels, player->type, data);
 187     }
 188     if(alGetError() != AL_NO_ERROR)
 189     {
 190         fprintf(stderr, "Error buffering for playback\n");
 191         return 0;
 192     }
 193
 194     /* Now queue and start playback! */
 195     alSourceQueueBuffers(player->source, i, player->buffers);
 196     alSourcePlay(player->source);
 197     if(alGetError() != AL_NO_ERROR)
 198     {
 199         fprintf(stderr, "Error starting playback\n");
 200         return 0;
 201     }
 202
 203     return 1;
 204 }
 205
 206 static int UpdatePlayer(StreamPlayer *player)
 207 {
 208     ALint processed, state;
 209
 210     /* Get relevant source info */
 211     alGetSourcei(player->source, AL_SOURCE_STATE, &state);
 212     alGetSourcei(player->source, AL_BUFFERS_PROCESSED, &processed);
 213     if(alGetError() != AL_NO_ERROR)
 214     {
 215         fprintf(stderr, "Error checking source state\n");
 216         return 0;
 217     }
 218
 219     /* Unqueue and handle each processed buffer */
 220     while(processed > 0)
 221     {
 222         ALuint bufid;
 223         uint8_t *data;
 224         size_t got;
 225
 226         alSourceUnqueueBuffers(player->source, 1, &bufid);
 227         processed--;
 228
 229         /* Read the next chunk of data, refill the buffer, and queue it
 230          * back on the source */
 231         data = getAudioData(player->file, &got);
 232         if(data != NULL)
 233         {
 234             alBufferSamplesSOFT(bufid, player->rate, player->format,
 235                                 BytesToFrames(got, player->channels, player->type),
 236                                 player->channels, player->type, data);
 237             alSourceQueueBuffers(player->source, 1, &bufid);
 238         }
 239         if(alGetError() != AL_NO_ERROR)
 240         {
 241             fprintf(stderr, "Error buffering data\n");
 242             return 0;
 243         }
 244     }
 245
 246     /* Make sure the source hasn't underrun */
 247     if(state != AL_PLAYING && state != AL_PAUSED)
 248     {
 249         ALint queued;
 250
 251         /* If no buffers are queued, playback is finished */
 252         alGetSourcei(player->source, AL_BUFFERS_QUEUED, &queued);
 253         if(queued == 0)
 254             return 0;
 255
 256         alSourcePlay(player->source);
 257         if(alGetError() != AL_NO_ERROR)
 258         {
 259             fprintf(stderr, "Error restarting playback\n");
 260             return 0;
 261         }
 262     }
 263
 264     return 1;
 265 }
 266
 267
 268 int main(int argc, char **argv)
 269 {
 270     StreamPlayer *player;
 271     int i;
 272
 273     /* Print out usage if no file was specified */
 274     if(argc < 2)
 275     {
 276         fprintf(stderr, "Usage: %s <filenames...>\n", argv[0]);
 277         return 1;
 278     }
 279
 280     if(InitAL() != 0)
 281         return 1;
 282
 283     if(alIsExtensionPresent("AL_SOFT_buffer_samples"))
 284     {
 285         printf("AL_SOFT_buffer_samples supported!\n");
 286         alBufferSamplesSOFT = alGetProcAddress("alBufferSamplesSOFT");
 287         alIsBufferFormatSupportedSOFT = alGetProcAddress("alIsBufferFormatSupportedSOFT");
 288     }
 289     else
 290         printf("AL_SOFT_buffer_samples not supported\n");
 291
 292     player = NewPlayer();
 293
 294     /* Play each file listed on the command line */
 295     for(i = 1;i < argc;i++)
 296     {
 297         const char *namepart;
 298
 299         if(!OpenPlayerFile(player, argv[i]))
 300             continue;
 301
 302         /* Get the name portion, without the path, for display. */
 303         namepart = strrchr(argv[i], '/');
 304         if(namepart || (namepart=strrchr(argv[i], '\\')))
 305             namepart++;
 306         else
 307             namepart = argv[i];
 308
 309         printf("Playing: %s (%s, %s, %dhz)\n", namepart,
 310                TypeName(player->type), ChannelsName(player->channels),
 311                player->rate);
 312         fflush(stdout);
 313
 314         if(!StartPlayer(player))
 315         {
 316             ClosePlayerFile(player);
 317             continue;
 318         }
 319
 320         while(UpdatePlayer(player))
 321             Sleep(10);
 322
 323         /* All done with this file. Close it and go to the next */
 324         ClosePlayerFile(player);
 325     }
 326     printf("Done.\n");
 327
 328     /* All files done. Delete the player, and close OpenAL */
 329     DeletePlayer(player);
 330     player = NULL;
 331
 332     CloseAL();
 333
 334     return 0;
 335 }