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 <assert.h>
  31
  32 #include "SDL_sound.h"
  33 #include "SDL_audio.h"
  34 #include "SDL_stdinc.h"
  35
  36 #include "AL/al.h"
  37
  38 #include "common/alhelpers.h"
  39
  40
  41 #ifndef SDL_AUDIO_MASK_BITSIZE
  42 #define SDL_AUDIO_MASK_BITSIZE (0xFF)
  43 #endif
  44 #ifndef SDL_AUDIO_BITSIZE
  45 #define SDL_AUDIO_BITSIZE(x) (x & SDL_AUDIO_MASK_BITSIZE)
  46 #endif
  47
  48 /* Define the number of buffers and buffer size (in milliseconds) to use. 4
  49  * buffers with 200ms each gives a nice per-chunk size, and lets the queue last
  50  * for almost one second. */
  51 #define NUM_BUFFERS 4
  52 #define BUFFER_TIME_MS 200
  53
  54 typedef struct StreamPlayer {
  55     /* These are the buffers and source to play out through OpenAL with */
  56     ALuint buffers[NUM_BUFFERS];
  57     ALuint source;
  58
  59     /* Handle for the audio file */
  60     Sound_Sample *sample;
  61
  62     /* The format of the output stream */
  63     ALenum format;
  64     ALsizei srate;
  65 } StreamPlayer;
  66
  67 static StreamPlayer *NewPlayer(void);
  68 static void DeletePlayer(StreamPlayer *player);
  69 static int OpenPlayerFile(StreamPlayer *player, const char *filename);
  70 static void ClosePlayerFile(StreamPlayer *player);
  71 static int StartPlayer(StreamPlayer *player);
  72 static int UpdatePlayer(StreamPlayer *player);
  73
  74 /* Creates a new player object, and allocates the needed OpenAL source and
  75  * buffer objects. Error checking is simplified for the purposes of this
  76  * example, and will cause an abort if needed. */
  77 static StreamPlayer *NewPlayer(void)
  78 {
  79     StreamPlayer *player;
  80
  81     player = calloc(1, sizeof(*player));
  82     assert(player != NULL);
  83
  84     /* Generate the buffers and source */
  85     alGenBuffers(NUM_BUFFERS, player->buffers);
  86     assert(alGetError() == AL_NO_ERROR && "Could not create buffers");
  87
  88     alGenSources(1, &player->source);
  89     assert(alGetError() == AL_NO_ERROR && "Could not create source");
  90
  91     /* Set parameters so mono sources play out the front-center speaker and
  92      * won't distance attenuate. */
  93     alSource3i(player->source, AL_POSITION, 0, 0, -1);
  94     alSourcei(player->source, AL_SOURCE_RELATIVE, AL_TRUE);
  95     alSourcei(player->source, AL_ROLLOFF_FACTOR, 0);
  96     assert(alGetError() == AL_NO_ERROR && "Could not set source parameters");
  97
  98     return player;
  99 }
 100
 101 /* Destroys a player object, deleting the source and buffers. No error handling
 102  * since these calls shouldn't fail with a properly-made player object. */
 103 static void DeletePlayer(StreamPlayer *player)
 104 {
 105     ClosePlayerFile(player);
 106
 107     alDeleteSources(1, &player->source);
 108     alDeleteBuffers(NUM_BUFFERS, player->buffers);
 109     if(alGetError() != AL_NO_ERROR)
 110         fprintf(stderr, "Failed to delete object IDs\n");
 111
 112     memset(player, 0, sizeof(*player));
 113     free(player);
 114 }
 115
 116
 117 /* Opens the first audio stream of the named file. If a file is already open,
 118  * it will be closed first. */
 119 static int OpenPlayerFile(StreamPlayer *player, const char *filename)
 120 {
 121     Uint32 frame_size;
 122
 123     ClosePlayerFile(player);
 124
 125     /* Open the file and get the first stream from it */
 126     player->sample = Sound_NewSampleFromFile(filename, NULL, 0);
 127     if(!player->sample)
 128     {
 129         fprintf(stderr, "Could not open audio in %s\n", filename);
 130         goto error;
 131     }
 132
 133     /* Get the stream format, and figure out the OpenAL format */
 134     if(player->sample->actual.channels == 1)
 135     {
 136         if(player->sample->actual.format == AUDIO_U8)
 137             player->format = AL_FORMAT_MONO8;
 138         else if(player->sample->actual.format == AUDIO_S16SYS)
 139             player->format = AL_FORMAT_MONO16;
 140         else
 141         {
 142             fprintf(stderr, "Unsupported sample format: 0x%04x\n", player->sample->actual.format);
 143             goto error;
 144         }
 145     }
 146     else if(player->sample->actual.channels == 2)
 147     {
 148         if(player->sample->actual.format == AUDIO_U8)
 149             player->format = AL_FORMAT_STEREO8;
 150         else if(player->sample->actual.format == AUDIO_S16SYS)
 151             player->format = AL_FORMAT_STEREO16;
 152         else
 153         {
 154             fprintf(stderr, "Unsupported sample format: 0x%04x\n", player->sample->actual.format);
 155             goto error;
 156         }
 157     }
 158     else
 159     {
 160         fprintf(stderr, "Unsupported channel count: %d\n", player->sample->actual.channels);
 161         goto error;
 162     }
 163     player->srate = (ALsizei)player->sample->actual.rate;
 164
 165     frame_size = player->sample->actual.channels *
 166         SDL_AUDIO_BITSIZE(player->sample->actual.format) / 8;
 167
 168     /* Set the buffer size, given the desired millisecond length. */
 169     Sound_SetBufferSize(player->sample, (Uint32)((Uint64)player->srate*BUFFER_TIME_MS/1000) *
 170                                         frame_size);
 171
 172     return 1;
 173
 174 error:
 175     if(player->sample)
 176         Sound_FreeSample(player->sample);
 177     player->sample = NULL;
 178
 179     return 0;
 180 }
 181
 182 /* Closes the audio file stream */
 183 static void ClosePlayerFile(StreamPlayer *player)
 184 {
 185     if(player->sample)
 186         Sound_FreeSample(player->sample);
 187     player->sample = NULL;
 188 }
 189
 190
 191 /* Prebuffers some audio from the file, and starts playing the source */
 192 static int StartPlayer(StreamPlayer *player)
 193 {
 194     ALsizei i;
 195
 196     /* Rewind the source position and clear the buffer queue */
 197     alSourceRewind(player->source);
 198     alSourcei(player->source, AL_BUFFER, 0);
 199
 200     /* Fill the buffer queue */
 201     for(i = 0;i < NUM_BUFFERS;i++)
 202     {
 203         /* Get some data to give it to the buffer */
 204         Uint32 slen = Sound_Decode(player->sample);
 205         if(slen == 0) break;
 206
 207         alBufferData(player->buffers[i], player->format, player->sample->buffer, (ALsizei)slen,
 208             player->srate);
 209     }
 210     if(alGetError() != AL_NO_ERROR)
 211     {
 212         fprintf(stderr, "Error buffering for playback\n");
 213         return 0;
 214     }
 215
 216     /* Now queue and start playback! */
 217     alSourceQueueBuffers(player->source, i, player->buffers);
 218     alSourcePlay(player->source);
 219     if(alGetError() != AL_NO_ERROR)
 220     {
 221         fprintf(stderr, "Error starting playback\n");
 222         return 0;
 223     }
 224
 225     return 1;
 226 }
 227
 228 static int UpdatePlayer(StreamPlayer *player)
 229 {
 230     ALint processed, state;
 231
 232     /* Get relevant source info */
 233     alGetSourcei(player->source, AL_SOURCE_STATE, &state);
 234     alGetSourcei(player->source, AL_BUFFERS_PROCESSED, &processed);
 235     if(alGetError() != AL_NO_ERROR)
 236     {
 237         fprintf(stderr, "Error checking source state\n");
 238         return 0;
 239     }
 240
 241     /* Unqueue and handle each processed buffer */
 242     while(processed > 0)
 243     {
 244         ALuint bufid;
 245         Uint32 slen;
 246
 247         alSourceUnqueueBuffers(player->source, 1, &bufid);
 248         processed--;
 249
 250         if((player->sample->flags&(SOUND_SAMPLEFLAG_EOF|SOUND_SAMPLEFLAG_ERROR)))
 251             continue;
 252
 253         /* Read the next chunk of data, refill the buffer, and queue it
 254          * back on the source */
 255         slen = Sound_Decode(player->sample);
 256         if(slen > 0)
 257         {
 258             alBufferData(bufid, player->format, player->sample->buffer, (ALsizei)slen,
 259                 player->srate);
 260             alSourceQueueBuffers(player->source, 1, &bufid);
 261         }
 262         if(alGetError() != AL_NO_ERROR)
 263         {
 264             fprintf(stderr, "Error buffering data\n");
 265             return 0;
 266         }
 267     }
 268
 269     /* Make sure the source hasn't underrun */
 270     if(state != AL_PLAYING && state != AL_PAUSED)
 271     {
 272         ALint queued;
 273
 274         /* If no buffers are queued, playback is finished */
 275         alGetSourcei(player->source, AL_BUFFERS_QUEUED, &queued);
 276         if(queued == 0)
 277             return 0;
 278
 279         alSourcePlay(player->source);
 280         if(alGetError() != AL_NO_ERROR)
 281         {
 282             fprintf(stderr, "Error restarting playback\n");
 283             return 0;
 284         }
 285     }
 286
 287     return 1;
 288 }
 289
 290
 291 int main(int argc, char **argv)
 292 {
 293     StreamPlayer *player;
 294     int i;
 295
 296     /* Print out usage if no arguments were specified */
 297     if(argc < 2)
 298     {
 299         fprintf(stderr, "Usage: %s [-device <name>] <filenames...>\n", argv[0]);
 300         return 1;
 301     }
 302
 303     argv++; argc--;
 304     if(InitAL(&argv, &argc) != 0)
 305         return 1;
 306
 307     Sound_Init();
 308
 309     player = NewPlayer();
 310
 311     /* Play each file listed on the command line */
 312     for(i = 0;i < argc;i++)
 313     {
 314         const char *namepart;
 315
 316         if(!OpenPlayerFile(player, argv[i]))
 317             continue;
 318
 319         /* Get the name portion, without the path, for display. */
 320         namepart = strrchr(argv[i], '/');
 321         if(namepart || (namepart=strrchr(argv[i], '\\')))
 322             namepart++;
 323         else
 324             namepart = argv[i];
 325
 326         printf("Playing: %s (%s, %dhz)\n", namepart, FormatName(player->format), player->srate);
 327         fflush(stdout);
 328
 329         if(!StartPlayer(player))
 330         {
 331             ClosePlayerFile(player);
 332             continue;
 333         }
 334
 335         while(UpdatePlayer(player))
 336             al_nssleep(10000000);
 337
 338         /* All done with this file. Close it and go to the next */
 339         ClosePlayerFile(player);
 340     }
 341     printf("Done.\n");
 342
 343     /* All files done. Delete the player, and close down SDL_sound and OpenAL */
 344     DeletePlayer(player);
 345     player = NULL;
 346
 347     Sound_Quit();
 348     CloseAL();
 349
 350     return 0;
 351 }