src/audio/nto/SDL_nto_audio.c
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FUNCTIONS
This source file includes following functions.
- init_pcm_cparams
- Audio_Available
- Audio_DeleteDevice
- Audio_CreateDevice
- NTO_WaitAudio
- NTO_PlayAudio
- NTO_GetAudioBuf
- NTO_CloseAudio
- NTO_OpenAudio
1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9
10 This library 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 GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with this library; if not, write to the Free
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 Sam Lantinga
20 slouken@devolution.com
21 */
22
23
24
25 /* Allow access to a raw mixing buffer */
26
27 #include <stdlib.h>
28 #include <stdio.h>
29 #include <string.h>
30 #include <errno.h>
31 #include <unistd.h>
32 #include <fcntl.h>
33 #include <signal.h>
34 #include <sys/types.h>
35 #include <sys/time.h>
36 #include <sched.h>
37 #include <sys/asoundlib.h>
38
39 #include "SDL_audio.h"
40 #include "SDL_error.h"
41 #include "SDL_audiomem.h"
42 #include "SDL_audio_c.h"
43 #include "SDL_timer.h"
44 #include "SDL_nto_audio.h"
45
46 /* The tag name used by NTO audio */
47 #define DRIVER_NAME "nto"
48
49 /* default card and device numbers as listed in dev/snd */
50 static int card_no = 0;
51 static int device_no = 0;
52
53 /* default channel communication parameters */
54 #define DEFAULT_CPARAMS_RATE 22050
55 #define DEFAULT_CPARAMS_VOICES 1
56 #define DEFAULT_CPARAMS_FRAG_SIZE 4096 //was 512
57 #define DEFAULT_CPARAMS_FRAGS_MIN 1
58 #define DEFAULT_CPARAMS_FRAGS_MAX -1
59
60 /* Open the audio device for playback, and don't block if busy */
61 #define OPEN_FLAGS SND_PCM_OPEN_PLAYBACK
62
63 /* Audio driver functions */
64 static int NTO_OpenAudio(_THIS, SDL_AudioSpec *spec);
65 static void NTO_WaitAudio(_THIS);
66 static void NTO_PlayAudio(_THIS);
67 static Uint8 *NTO_GetAudioBuf(_THIS);
68 static void NTO_CloseAudio(_THIS);
69
70 static snd_pcm_channel_status_t cstatus;
71 static snd_pcm_channel_params_t cparams;
72 static snd_pcm_channel_setup_t csetup;
73
74 /* PCM transfer channel parameters initialize function */
75 static void init_pcm_cparams(snd_pcm_channel_params_t* cparams)
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76 {
77 memset(cparams,0,sizeof(snd_pcm_channel_params_t));
78
79 cparams->channel = SND_PCM_CHANNEL_PLAYBACK;
80 cparams->mode = SND_PCM_MODE_BLOCK;
81 cparams->start_mode = SND_PCM_START_DATA; //_FULL
82 cparams->stop_mode = SND_PCM_STOP_STOP;
83 cparams->format.format = SND_PCM_SFMT_S16_LE;
84 cparams->format.interleave = 1;
85 cparams->format.rate = DEFAULT_CPARAMS_RATE;
86 cparams->format.voices = DEFAULT_CPARAMS_VOICES;
87 cparams->buf.block.frag_size = DEFAULT_CPARAMS_FRAG_SIZE;
88 cparams->buf.block.frags_min = DEFAULT_CPARAMS_FRAGS_MIN;
89 cparams->buf.block.frags_max = DEFAULT_CPARAMS_FRAGS_MAX;
90 }
91
92 /* Audio driver bootstrap functions */
93
94 static int Audio_Available(void)
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95 /*
96 See if we can open a nonblocking channel.
97 Return value '1' means we can.
98 Return value '0' means we cannot.
99 */
100 {
101 int available;
102 int rval;
103 snd_pcm_t *handle;
104
105 available = 0;
106 handle = NULL;
107
108 //JB modified to take advantage of software mixer
109 rval = snd_pcm_open_preferred(&handle, &card_no, &device_no, OPEN_FLAGS);
110
111 if (rval >= 0)
112 {
113 available = 1;
114
115 if ((rval = snd_pcm_close(handle)) < 0)
116 {
117 SDL_SetError("snd_pcm_close failed: %s\n",snd_strerror(rval));
118 available = 0;
119 }
120 }
121 else
122 {
123
124 SDL_SetError("snd_pcm_open failed: %s\n", snd_strerror(rval));
125 }
126
127 #ifdef DEBUG_AUDIO
128 fprintf(stderr,"AudioAvailable rtns %d\n", available);
129 #endif
130 return(available);
131 }
132
133 static void Audio_DeleteDevice(SDL_AudioDevice *device)
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134 {
135 #ifdef DEBUG_AUDIO
136 fprintf(stderr,"Audio_DeleteDevice\n");
137 #endif
138
139
140 free(device->hidden);
141 free(device);
142 }
143
144 static SDL_AudioDevice *Audio_CreateDevice(int devindex)
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145 {
146 SDL_AudioDevice *this;
147 #ifdef DEBUG_AUDIO
148 fprintf(stderr,"Audio_CreateDevice\n");
149 #endif
150 /* Initialize all variables that we clean on shutdown */
151 this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice));
152 if ( this ) {
153 memset(this, 0, (sizeof *this));
154 this->hidden = (struct SDL_PrivateAudioData *)
155 malloc((sizeof *this->hidden));
156 }
157 if ( (this == NULL) || (this->hidden == NULL) ) {
158 SDL_OutOfMemory();
159 if ( this ) {
160 free(this);
161 }
162 return(0);
163 }
164 memset(this->hidden, 0, (sizeof *this->hidden));
165 audio_handle = NULL;
166
167 /* Set the function pointers */
168 this->OpenAudio = NTO_OpenAudio;
169 this->WaitAudio = NTO_WaitAudio;
170 this->PlayAudio = NTO_PlayAudio;
171 this->GetAudioBuf = NTO_GetAudioBuf;
172 this->CloseAudio = NTO_CloseAudio;
173
174 this->free = Audio_DeleteDevice;
175
176 return this;
177 }
178
179 /* Don't change the name from "ALSA_bootstrap" - that's how it's called */
180 AudioBootStrap ALSA_bootstrap = {
181 DRIVER_NAME, "Neutrino PCM audio",
182 Audio_Available, Audio_CreateDevice
183 };
184
185 /* This function waits until it is possible to write a full sound buffer */
186 static void NTO_WaitAudio(_THIS)
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187 {
188 int rval;
189 int totalbytes,roomavail;
190 /*we consider a full sound buffer to be of size pcm_len bytes */
191
192 #ifdef DEBUG_AUDIO
193 fprintf(stderr,"NTO_WaitAudio\n");
194 #endif
195
196 while(1)
197 {
198 memset(&cstatus, 0, sizeof(cstatus));
199 if( (rval = snd_pcm_plugin_status(audio_handle, &cstatus)) < 0 )
200 {
201 SDL_SetError("snd_pcm_plugin_status failed: %s\n", snd_strerror(rval));
202 return;
203 }
204
205 totalbytes = csetup.buf.block.frag_size *csetup.buf.block.frags;
206 roomavail = totalbytes - cstatus.count;
207
208 #ifdef DEBUG_AUDIO
209 fprintf(stderr,"NTO_WaitAudio roomavail %d pcm_len %d\n",roomavail,pcm_len);
210 #endif
211
212 if ((roomavail >= pcm_len) || (roomavail < 0))
213 return;
214
215 SDL_Delay(10);
216 }
217
218 }
219
220
221
222 static void NTO_PlayAudio(_THIS)
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223 {
224 int written, rval;
225 int towrite;
226
227 #ifdef DEBUG_AUDIO
228 fprintf(stderr, "NTO_PlayAudio\n");
229 #endif
230
231 if( !this->enabled)
232 return;
233
234 towrite = pcm_len;
235
236
237 /* Write the audio data, checking for EAGAIN (buffer full) and underrun */
238 do {
239 written = snd_pcm_plugin_write(audio_handle, pcm_buf, towrite);
240 #ifdef DEBUG_AUDIO
241 fprintf(stderr, "NTO_PlayAudio: written = %d towrite = %d\n",written,towrite);
242 #endif
243 if (written != towrite)
244 {
245 if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
246 {
247 SDL_Delay(1); /* Let a little CPU time go by and try to write again */
248 #ifdef DEBUG_AUDIO
249 fprintf(stderr, "errno == EAGAIN written %d\n", written);
250 towrite -= written; //we wrote some data
251 #endif
252 continue;
253 }
254 else if((errno == EINVAL) || (errno == EIO))
255 {
256 #ifdef DEBUG_AUDIO
257 if(errno == EIO)
258 fprintf(stderr,"snd_pcm_plugin_write failed EIO: %s\n", snd_strerror(written));
259 if(errno == EINVAL)
260 fprintf(stderr,"snd_pcm_plugin_write failed EINVAL: %s\n", snd_strerror(written));
261
262 #endif
263
264 memset(&cstatus, 0, sizeof(cstatus));
265 if( (rval = snd_pcm_plugin_status(audio_handle, &cstatus)) < 0 )
266 {
267 #ifdef DEBUG_AUDIO
268 fprintf(stderr, "snd_pcm_plugin_status failed %s\n",snd_strerror(rval));
269 #endif
270 SDL_SetError("snd_pcm_plugin_status failed: %s\n", snd_strerror(rval));
271 return;
272 }
273
274 if ( (cstatus.status == SND_PCM_STATUS_UNDERRUN) ||
275 (cstatus.status == SND_PCM_STATUS_READY) )
276 {
277 #ifdef DEBUG_AUDIO
278 fprintf(stderr, "buffer underrun\n");
279 #endif
280 if ( (rval = snd_pcm_plugin_prepare (audio_handle,SND_PCM_CHANNEL_PLAYBACK)) < 0 )
281 {
282 #ifdef DEBUG_AUDIO
283 fprintf(stderr, "NTO_PlayAudio: prepare failed %s\n",snd_strerror(rval));
284 #endif
285 SDL_SetError("snd_pcm_plugin_prepare failed: %s\n",snd_strerror(rval) );
286 return;
287 }
288
289 }
290 continue;
291 }
292 else
293 {
294 #ifdef DEBUG_AUDIO
295 fprintf(stderr, "NTO_PlayAudio: snd_pcm_plugin_write failed unknown errno %d %s\n",errno, snd_strerror(rval));
296 #endif
297 return;
298
299 }
300
301 }
302 else
303 {
304 towrite -= written; //we wrote all remaining data
305 }
306 } while ( (towrite > 0) && (this->enabled) );
307
308 /* If we couldn't write, assume fatal error for now */
309 if ( towrite != 0 ) {
310 this->enabled = 0;
311 }
312 return;
313 }
314
315 static Uint8 *NTO_GetAudioBuf(_THIS)
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316 {
317 #ifdef DEBUG_AUDIO
318 fprintf(stderr, "NTO_GetAudioBuf: pcm_buf %X\n",(Uint8 *)pcm_buf);
319 #endif
320 return(pcm_buf);
321 }
322
323 static void NTO_CloseAudio(_THIS)
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324 {
325 int rval;
326
327 #ifdef DEBUG_AUDIO
328 fprintf(stderr, "NTO_CloseAudio\n");
329 #endif
330
331 this->enabled = 0;
332
333 if ( audio_handle != NULL ) {
334 if ((rval = snd_pcm_plugin_flush(audio_handle,SND_PCM_CHANNEL_PLAYBACK)) < 0)
335 {
336 SDL_SetError("snd_pcm_plugin_flush failed: %s\n",snd_strerror(rval));
337 return;
338 }
339 if ((rval = snd_pcm_close(audio_handle)) < 0)
340 {
341 SDL_SetError("snd_pcm_close failed: %s\n",snd_strerror(rval));
342 return;
343 }
344 audio_handle = NULL;
345 }
346 }
347
348 static int NTO_OpenAudio(_THIS, SDL_AudioSpec *spec)
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349 {
350 int rval;
351 int format;
352 Uint16 test_format;
353 int twidth;
354 int found;
355
356 #ifdef DEBUG_AUDIO
357 fprintf(stderr, "NTO_OpenAudio\n");
358 #endif
359
360 audio_handle = NULL;
361 this->enabled = 0;
362
363 if ( pcm_buf != NULL ) {
364 free((Uint8 *)pcm_buf);
365 pcm_buf = NULL;
366 }
367
368 /* initialize channel transfer parameters to default */
369 init_pcm_cparams(&cparams);
370
371 /* Open the audio device */
372
373 rval = snd_pcm_open_preferred(&audio_handle, &card_no, &device_no, OPEN_FLAGS);
374 if ( rval < 0 ) {
375 SDL_SetError("snd_pcm_open failed: %s\n", snd_strerror(rval));
376 return(-1);
377 }
378
379 /* set to nonblocking mode */
380 if ((rval = snd_pcm_nonblock_mode(audio_handle, 1))<0) //I assume 1 means on
381 {
382 SDL_SetError("snd_pcm_nonblock_mode failed: %s\n", snd_strerror(rval));
383 return(-1);
384 }
385
386 /* enable count status parameter */
387 if ((rval = snd_plugin_set_disable(audio_handle, PLUGIN_DISABLE_MMAP))<0)
388 {
389 SDL_SetError("snd_plugin_set_disable failed: %s\n", snd_strerror(rval));
390 return(-1);
391 }
392
393
394 /* Try for a closest match on audio format */
395 format = 0;
396 found = 0; // can't use format as SND_PCM_SFMT_U8 = 0 in nto
397 for ( test_format = SDL_FirstAudioFormat(spec->format); !found ; )
398
399 {
400 #ifdef DEBUG_AUDIO
401 fprintf(stderr, "Trying format 0x%4.4x spec->samples %d\n", test_format,spec->samples);
402 #endif
403 /* if match found set format to equivalent ALSA format */
404 switch ( test_format ) {
405 case AUDIO_U8:
406 format = SND_PCM_SFMT_U8;
407 cparams.buf.block.frag_size = spec->samples * spec->channels;
408 found = 1;
409 break;
410 case AUDIO_S8:
411 format = SND_PCM_SFMT_S8;
412 cparams.buf.block.frag_size = spec->samples * spec->channels;
413 found = 1;
414 break;
415 case AUDIO_S16LSB:
416 format = SND_PCM_SFMT_S16_LE;
417 cparams.buf.block.frag_size = spec->samples*2 * spec->channels;
418 found = 1;
419 break;
420 case AUDIO_S16MSB:
421 format = SND_PCM_SFMT_S16_BE;
422 cparams.buf.block.frag_size = spec->samples*2 * spec->channels;
423 found = 1;
424 break;
425 case AUDIO_U16LSB:
426 format = SND_PCM_SFMT_U16_LE;
427 cparams.buf.block.frag_size = spec->samples*2 * spec->channels;
428 found = 1;
429 break;
430 case AUDIO_U16MSB:
431 format = SND_PCM_SFMT_U16_BE;
432 cparams.buf.block.frag_size = spec->samples*2 * spec->channels;
433 found = 1;
434 break;
435 default:
436 break;
437 }
438 if ( ! found ) {
439 test_format = SDL_NextAudioFormat();
440 }
441 }
442
443 /* assumes test_format not 0 on success */
444 if ( test_format == 0 ) {
445 SDL_SetError("Couldn't find any hardware audio formats");
446 return(-1);
447 }
448
449 spec->format = test_format;
450
451 /* Set the audio format */
452 cparams.format.format = format;
453
454 /* Set mono or stereo audio (currently only two channels supported) */
455 cparams.format.voices = spec->channels;
456
457 #ifdef DEBUG_AUDIO
458 fprintf(stderr,"intializing channels %d\n", cparams.format.voices);
459 #endif
460
461
462 /* Set rate */
463 cparams.format.rate = spec->freq ;
464
465 /* Setup the transfer parameters according to cparams */
466 rval = snd_pcm_plugin_params(audio_handle, &cparams);
467 if (rval < 0) {
468 SDL_SetError("snd_pcm_channel_params failed: %s\n", snd_strerror (rval));
469 return(-1);
470 }
471
472 /* Make sure channel is setup right one last time */
473 memset( &csetup, 0, sizeof( csetup ) );
474 csetup.channel = SND_PCM_CHANNEL_PLAYBACK;
475 if ( snd_pcm_plugin_setup( audio_handle, &csetup ) < 0 )
476 {
477 SDL_SetError("Unable to setup playback channel\n" );
478 return(-1);
479 }
480 else
481 {
482 #ifdef DEBUG_AUDIO
483 fprintf(stderr,"requested format: %d\n",cparams.format.format);
484 fprintf(stderr,"requested frag size: %d\n",cparams.buf.block.frag_size);
485 fprintf(stderr,"requested max frags: %d\n\n",cparams.buf.block.frags_max);
486
487 fprintf(stderr,"real format: %d\n", csetup.format.format );
488 fprintf(stderr,"real frag size : %d\n", csetup.buf.block.frag_size );
489 fprintf(stderr,"real max frags : %d\n", csetup.buf.block.frags_max );
490 #endif // DEBUG_AUDIO
491 }
492
493
494 /* Allocate memory to the audio buffer and initialize with silence
495 (Note that buffer size must be a multiple of fragment size, so find closest multiple)
496 */
497
498 twidth = snd_pcm_format_width(format);
499 if (twidth < 0) {
500 printf("snd_pcm_format_width failed\n");
501 twidth = 0;
502 }
503
504 #ifdef DEBUG_AUDIO
505 fprintf(stderr,"format is %d bits wide\n",twidth);
506 #endif
507
508 pcm_len = spec->size ;
509
510
511 #ifdef DEBUG_AUDIO
512 fprintf(stderr,"pcm_len set to %d\n", pcm_len);
513 #endif
514
515 if (pcm_len == 0)
516 {
517 pcm_len = csetup.buf.block.frag_size;
518 }
519
520 pcm_buf = (Uint8*)malloc(pcm_len);
521 if (pcm_buf == NULL) {
522 SDL_SetError("pcm_buf malloc failed\n");
523 return(-1);
524 }
525 memset(pcm_buf,spec->silence,pcm_len);
526
527 #ifdef DEBUG_AUDIO
528 fprintf(stderr,"pcm_buf malloced and silenced.\n");
529 #endif
530
531 /* get the file descriptor */
532 if( (audio_fd = snd_pcm_file_descriptor(audio_handle, SND_PCM_CHANNEL_PLAYBACK)) < 0)
533 {
534 fprintf(stderr, "snd_pcm_file_descriptor failed with error code: %d\n", audio_fd);
535 }
536
537 /* Trigger audio playback */
538 rval = snd_pcm_plugin_prepare( audio_handle, SND_PCM_CHANNEL_PLAYBACK);
539 if (rval < 0) {
540 SDL_SetError("snd_pcm_plugin_prepare failed: %s\n", snd_strerror (rval));
541 return(-1);
542 }
543
544 this->enabled = 1;
545
546 /* Get the parent process id (we're the parent of the audio thread) */
547 parent = getpid();
548
549 /* We're ready to rock and roll. :-) */
550 return(0);
551 }
552
553
554