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 <SDL_sound.h>
  34
  35 #include "AL/al.h"
  36 #include "AL/alc.h"
  37 #include "AL/alext.h"
  38
  39 #include "common/alhelpers.h"
  40
  41
  42 #ifndef SDL_AUDIO_MASK_BITSIZE
  43 #define SDL_AUDIO_MASK_BITSIZE (0xFF)
  44 #endif
  45 #ifndef SDL_AUDIO_BITSIZE
  46 #define SDL_AUDIO_BITSIZE(x) (x & SDL_AUDIO_MASK_BITSIZE)
  47 #endif
  48
  49 /* Define the number of buffers and buffer size (in milliseconds) to use. 4
  50  * buffers with 200ms each gives a nice per-chunk size, and lets the queue last
  51  * for almost one second. */
  52 #define NUM_BUFFERS 4
  53 #define BUFFER_TIME_MS 200
  54
  55 typedef struct StreamPlayer {
  56     /* These are the buffers and source to play out through OpenAL with */
  57     ALuint buffers[NUM_BUFFERS];
  58     ALuint source;
  59
  60     /* Handle for the audio file */
  61     Sound_Sample *sample;
  62
  63     /* The format of the output stream */
  64     ALenum format;
  65     ALsizei srate;
  66 } StreamPlayer;
  67
  68 static StreamPlayer *NewPlayer(void);
  69 static void DeletePlayer(StreamPlayer *player);
  70 static int OpenPlayerFile(StreamPlayer *player, const char *filename);
  71 static void ClosePlayerFile(StreamPlayer *player);
  72 static int StartPlayer(StreamPlayer *player);
  73 static int UpdatePlayer(StreamPlayer *player);
  74
  75 /* Creates a new player object, and allocates the needed OpenAL source and
  76  * buffer objects. Error checking is simplified for the purposes of this
  77  * example, and will cause an abort if needed. */
  78 static StreamPlayer *NewPlayer(void)
  79 {
  80     StreamPlayer *player;
  81
  82     player = calloc(1, sizeof(*player));
  83     assert(player != NULL);
  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     Uint32 frame_size;
 123
 124     ClosePlayerFile(player);
 125
 126     /* Open the file and get the first stream from it */
 127     player->sample = Sound_NewSampleFromFile(filename, NULL, 0);
 128     if(!player->sample)
 129     {
 130         fprintf(stderr, "Could not open audio in %s\n", filename);
 131         goto error;
 132     }
 133
 134     /* Get the stream format, and figure out the OpenAL format */
 135     if(player->sample->actual.channels == 1)
 136     {
 137         if(player->sample->actual.format == AUDIO_U8)
 138             player->format = AL_FORMAT_MONO8;
 139         else if(player->sample->actual.format == AUDIO_S16SYS)
 140             player->format = AL_FORMAT_MONO16;
 141         else
 142         {
 143             fprintf(stderr, "Unsupported sample format: 0x%04x\n", player->sample->actual.format);
 144             goto error;
 145         }
 146     }
 147     else if(player->sample->actual.channels == 2)
 148     {
 149         if(player->sample->actual.format == AUDIO_U8)
 150             player->format = AL_FORMAT_STEREO8;
 151         else if(player->sample->actual.format == AUDIO_S16SYS)
 152             player->format = AL_FORMAT_STEREO16;
 153         else
 154         {
 155             fprintf(stderr, "Unsupported sample format: 0x%04x\n", player->sample->actual.format);
 156             goto error;
 157         }
 158     }
 159     else
 160     {
 161         fprintf(stderr, "Unsupported channel count: %d\n", player->sample->actual.channels);
 162         goto error;
 163     }
 164     player->srate = player->sample->actual.rate;
 165
 166     frame_size = player->sample->actual.channels *
 167                  SDL_AUDIO_BITSIZE(player->sample->actual.format) / 8;
 168
 169     /* Set the buffer size, given the desired millisecond length. */
 170     Sound_SetBufferSize(player->sample, (Uint32)((Uint64)player->srate*BUFFER_TIME_MS/1000) *
 171                                         frame_size);
 172
 173     return 1;
 174
 175 error:
 176     if(player->sample)
 177         Sound_FreeSample(player->sample);
 178     player->sample = NULL;
 179
 180     return 0;
 181 }
 182
 183 /* Closes the audio file stream */
 184 static void ClosePlayerFile(StreamPlayer *player)
 185 {
 186     if(player->sample)
 187         Sound_FreeSample(player->sample);
 188     player->sample = NULL;
 189 }
 190
 191
 192 /* Prebuffers some audio from the file, and starts playing the source */
 193 static int StartPlayer(StreamPlayer *player)
 194 {
 195     size_t i;
 196
 197     /* Rewind the source position and clear the buffer queue */
 198     alSourceRewind(player->source);
 199     alSourcei(player->source, AL_BUFFER, 0);
 200
 201     /* Fill the buffer queue */
 202     for(i = 0;i < NUM_BUFFERS;i++)
 203     {
 204         /* Get some data to give it to the buffer */
 205         Uint32 slen = Sound_Decode(player->sample);
 206         if(slen == 0) break;
 207
 208         alBufferData(player->buffers[i], player->format,
 209                      player->sample->buffer, slen, player->srate);
 210     }
 211     if(alGetError() != AL_NO_ERROR)
 212     {
 213         fprintf(stderr, "Error buffering for playback\n");
 214         return 0;
 215     }
 216
 217     /* Now queue and start playback! */
 218     alSourceQueueBuffers(player->source, i, player->buffers);
 219     alSourcePlay(player->source);
 220     if(alGetError() != AL_NO_ERROR)
 221     {
 222         fprintf(stderr, "Error starting playback\n");
 223         return 0;
 224     }
 225
 226     return 1;
 227 }
 228
 229 static int UpdatePlayer(StreamPlayer *player)
 230 {
 231     ALint processed, state;
 232
 233     /* Get relevant source info */
 234     alGetSourcei(player->source, AL_SOURCE_STATE, &state);
 235     alGetSourcei(player->source, AL_BUFFERS_PROCESSED, &processed);
 236     if(alGetError() != AL_NO_ERROR)
 237     {
 238         fprintf(stderr, "Error checking source state\n");
 239         return 0;
 240     }
 241
 242     /* Unqueue and handle each processed buffer */
 243     while(processed > 0)
 244     {
 245         ALuint bufid;
 246         Uint32 slen;
 247
 248         alSourceUnqueueBuffers(player->source, 1, &bufid);
 249         processed--;
 250
 251         if((player->sample->flags&(SOUND_SAMPLEFLAG_EOF|SOUND_SAMPLEFLAG_ERROR)))
 252             continue;
 253
 254         /* Read the next chunk of data, refill the buffer, and queue it
 255          * back on the source */
 256         slen = Sound_Decode(player->sample);
 257         if(slen > 0)
 258         {
 259             alBufferData(bufid, player->format, player->sample->buffer, slen,
 260                          player->srate);
 261             alSourceQueueBuffers(player->source, 1, &bufid);
 262         }
 263         if(alGetError() != AL_NO_ERROR)
 264         {
 265             fprintf(stderr, "Error buffering data\n");
 266             return 0;
 267         }
 268     }
 269
 270     /* Make sure the source hasn't underrun */
 271     if(state != AL_PLAYING && state != AL_PAUSED)
 272     {
 273         ALint queued;
 274
 275         /* If no buffers are queued, playback is finished */
 276         alGetSourcei(player->source, AL_BUFFERS_QUEUED, &queued);
 277         if(queued == 0)
 278             return 0;
 279
 280         alSourcePlay(player->source);
 281         if(alGetError() != AL_NO_ERROR)
 282         {
 283             fprintf(stderr, "Error restarting playback\n");
 284             return 0;
 285         }
 286     }
 287
 288     return 1;
 289 }
 290
 291
 292 int main(int argc, char **argv)
 293 {
 294     StreamPlayer *player;
 295     int i;
 296
 297     /* Print out usage if no arguments were specified */
 298     if(argc < 2)
 299     {
 300         fprintf(stderr, "Usage: %s [-device <name>] <filenames...>\n", argv[0]);
 301         return 1;
 302     }
 303
 304     argv++; argc--;
 305     if(InitAL(&argv, &argc) != 0)
 306         return 1;
 307
 308     Sound_Init();
 309
 310     player = NewPlayer();
 311
 312     /* Play each file listed on the command line */
 313     for(i = 0;i < argc;i++)
 314     {
 315         const char *namepart;
 316
 317         if(!OpenPlayerFile(player, argv[i]))
 318             continue;
 319
 320         /* Get the name portion, without the path, for display. */
 321         namepart = strrchr(argv[i], '/');
 322         if(namepart || (namepart=strrchr(argv[i], '\\')))
 323             namepart++;
 324         else
 325             namepart = argv[i];
 326
 327         printf("Playing: %s (%s, %dhz)\n", namepart, FormatName(player->format),
 328                player->srate);
 329         fflush(stdout);
 330
 331         if(!StartPlayer(player))
 332         {
 333             ClosePlayerFile(player);
 334             continue;
 335         }
 336
 337         while(UpdatePlayer(player))
 338             al_nssleep(10000000);
 339
 340         /* All done with this file. Close it and go to the next */
 341         ClosePlayerFile(player);
 342     }
 343     printf("Done.\n");
 344
 345     /* All files done. Delete the player, and close down SDL_sound and OpenAL */
 346     DeletePlayer(player);
 347     player = NULL;
 348
 349     Sound_Quit();
 350     CloseAL();
 351
 352     return 0;
 353 }