apps/pcmbuf.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2005 by Miika Pekkarinen
  11  *
  12  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19
  20 #include <stdbool.h>
  21 #include <stdio.h>
  22 #include "config.h"
  23 #include "debug.h"
  24 #include "panic.h"
  25 #include <kernel.h>
  26 #include "pcmbuf.h"
  27 #include "pcm.h"
  28 #include "logf.h"
  29 #ifndef SIMULATOR
  30 #include "cpu.h"
  31 #endif
  32 #include "system.h"
  33 #include <string.h>
  34 #include "buffer.h"
  35 #include "settings.h"
  36 #include "audio.h"
  37 #include "voice_thread.h"
  38 #include "dsp.h"
  39 #include "thread.h"
  40
  41 /* Define PCMBUF_MUTING if the codec requires muting to prevent pops */
  42 #if !defined(HAVE_UDA1380) && !defined(HAVE_TLV320) && !defined(HAVE_AS3514)
  43 #define PCMBUF_MUTING
  44 #endif
  45
  46 /* Clip sample to signed 16 bit range */
  47 static inline int32_t clip_sample_16(int32_t sample)
  48 {
  49     if ((int16_t)sample != sample)
  50         sample = 0x7fff ^ (sample >> 31);
  51     return sample;
  52 }
  53
  54 /* Keep watermark high for iPods at least (2s) */
  55 #define PCMBUF_WATERMARK     (NATIVE_FREQUENCY * 4 * 2)
  56
  57 /* Structure we can use to queue pcm chunks in memory to be played
  58  * by the driver code. */
  59 struct pcmbufdesc
  60 {
  61     void *addr;
  62     size_t size;
  63     struct pcmbufdesc* link;
  64     /* Call this when the buffer has been played */
  65     void (*callback)(void);
  66 };
  67
  68 #define PCMBUF_DESCS(bufsize) \
  69     ((bufsize) / PCMBUF_MINAVG_CHUNK)
  70 #define PCMBUF_DESCS_SIZE(bufsize) \
  71     (PCMBUF_DESCS(bufsize)*sizeof(struct pcmbufdesc))
  72
  73 /* Size of the PCM buffer. */
  74 static size_t pcmbuf_size IDATA_ATTR = 0;
  75 static char *pcmbuf_bufend IDATA_ATTR;
  76 static char *audiobuffer IDATA_ATTR;
  77 /* Current audio buffer write index. */
  78 static size_t audiobuffer_pos IDATA_ATTR;
  79 /* Amount audiobuffer_pos will be increased.*/
  80 static size_t audiobuffer_fillpos IDATA_ATTR;
  81 static char *fadebuf IDATA_ATTR;
  82 static char *voicebuf IDATA_ATTR;
  83
  84 static void (*pcmbuf_event_handler)(void) IDATA_ATTR;
  85 static void (*position_callback)(size_t size) IDATA_ATTR;
  86
  87 /* Crossfade related state */
  88 static bool crossfade_enabled;
  89 static bool crossfade_enabled_pending;
  90 static bool crossfade_mixmode;
  91 static bool crossfade_active IDATA_ATTR;
  92 static bool crossfade_init IDATA_ATTR;
  93
  94 /* Track the current location for processing crossfade */
  95 static struct pcmbufdesc *crossfade_chunk IDATA_ATTR;
  96 static size_t crossfade_sample IDATA_ATTR;
  97
  98 /* Counters for fading in new data */
  99 static size_t crossfade_fade_in_total IDATA_ATTR;
 100 static size_t crossfade_fade_in_rem IDATA_ATTR;
 101
 102 static size_t pcmbuf_descsize;
 103 static struct pcmbufdesc *pcmbuf_read IDATA_ATTR;
 104 static struct pcmbufdesc *pcmbuf_read_end IDATA_ATTR;
 105 static struct pcmbufdesc *pcmbuf_write IDATA_ATTR;
 106 static struct pcmbufdesc *pcmbuf_write_end IDATA_ATTR;
 107 static size_t last_chunksize IDATA_ATTR;
 108
 109 static size_t pcmbuf_unplayed_bytes IDATA_ATTR;
 110 static size_t pcmbuf_watermark IDATA_ATTR;
 111
 112 static struct pcmbufdesc *pcmbuf_mix_chunk IDATA_ATTR;
 113 static size_t pcmbuf_mix_sample IDATA_ATTR;
 114
 115 static bool low_latency_mode = false;
 116 static bool pcmbuf_flush;
 117
 118 #ifdef HAVE_PRIORITY_SCHEDULING
 119 static int codec_thread_priority = 0;
 120 #endif
 121
 122 extern struct thread_entry *codec_thread_p;
 123
 124 /* Helpful macros for use in conditionals this assumes some of the above
 125  * static variable names */
 126 #define NEED_FLUSH(position) \
 127     (audiobuffer_fillpos > PCMBUF_TARGET_CHUNK || position >= pcmbuf_size)
 128 #define LOW_DATA(quarter_secs) \
 129     (pcmbuf_unplayed_bytes < NATIVE_FREQUENCY * quarter_secs)
 130
 131 static bool prepare_insert(size_t length);
 132 static void pcmbuf_under_watermark(void);
 133 static bool pcmbuf_flush_fillpos(void);
 134
 135 #define CALL_IF_EXISTS(function, args...) if (function) function(args)
 136 /* This function has 2 major logical parts (separated by brackets both for
 137  * readability and variable scoping).  The first part performs the
 138  * operastions related to finishing off the last buffer we fed to the DMA.
 139  * The second part performs the operations involved in sending a new buffer
 140  * to the DMA.  Finally the function checks the status of the buffer and
 141  * boosts if necessary */
 142 static void pcmbuf_callback(unsigned char** start, size_t* size) ICODE_ATTR;
 143 static void pcmbuf_callback(unsigned char** start, size_t* size)
 144 {
 145     {
 146         struct pcmbufdesc *pcmbuf_current = pcmbuf_read;
 147         /* Take the finished buffer out of circulation */
 148         pcmbuf_read = pcmbuf_current->link;
 149
 150         /* The buffer is finished, call the callback functions */
 151         CALL_IF_EXISTS(position_callback, last_chunksize);
 152         CALL_IF_EXISTS(pcmbuf_current->callback);
 153
 154         /* Put the finished buffer back into circulation */
 155         pcmbuf_write_end->link = pcmbuf_current;
 156         pcmbuf_write_end = pcmbuf_current;
 157
 158         /* If we've read over the mix chunk while it's still mixing there */
 159         if (pcmbuf_current == pcmbuf_mix_chunk)
 160             pcmbuf_mix_chunk = NULL;
 161         /* If we've read over the crossfade chunk while it's still fading */
 162         if (pcmbuf_current == crossfade_chunk)
 163             crossfade_chunk = pcmbuf_read;
 164     }
 165
 166     {
 167         /* Send the new buffer to the pcm */
 168         struct pcmbufdesc *pcmbuf_new = pcmbuf_read;
 169         size_t *realsize = size;
 170         unsigned char** realstart = start;
 171         if(pcmbuf_new)
 172         {
 173             size_t current_size = pcmbuf_new->size;
 174
 175             pcmbuf_unplayed_bytes -= current_size;
 176             last_chunksize = current_size;
 177             *realsize = current_size;
 178             *realstart = pcmbuf_new->addr;
 179         }
 180         else
 181         {
 182             /* No more buffers */
 183             last_chunksize = 0;
 184             *realsize = 0;
 185             *realstart = NULL;
 186             CALL_IF_EXISTS(pcmbuf_event_handler);
 187         }
 188     }
 189 }
 190
 191 void pcmbuf_set_position_callback(void (*callback)(size_t size))
 192 {
 193     position_callback = callback;
 194 }
 195
 196 static void pcmbuf_set_watermark_bytes(void)
 197 {
 198     pcmbuf_watermark = (crossfade_enabled && pcmbuf_size) ?
 199         /* If crossfading, try to keep the buffer full other than 1 second */
 200         (pcmbuf_size - (NATIVE_FREQUENCY * 4 * 1)) :
 201         /* Otherwise, just keep it above 2 second */
 202         PCMBUF_WATERMARK;
 203 }
 204
 205 /* This is really just part of pcmbuf_flush_fillpos, but is easier to keep
 206  * in a separate function for the moment */
 207 static inline void pcmbuf_add_chunk(void)
 208 {
 209     register size_t size = audiobuffer_fillpos;
 210     /* Grab the next description to write, and change the write pointer */
 211     register struct pcmbufdesc *pcmbuf_current = pcmbuf_write;
 212     pcmbuf_write = pcmbuf_current->link;
 213     /* Fill in the values in the new buffer chunk */
 214     pcmbuf_current->addr = &audiobuffer[audiobuffer_pos];
 215     pcmbuf_current->size = size;
 216     pcmbuf_current->callback = pcmbuf_event_handler;
 217     pcmbuf_current->link = NULL;
 218     /* This is single use only */
 219     pcmbuf_event_handler = NULL;
 220     if (pcmbuf_read != NULL) {
 221         if (pcmbuf_flush)
 222         {
 223             pcmbuf_write_end->link = pcmbuf_read->link;
 224             pcmbuf_read->link = pcmbuf_current;
 225             while (pcmbuf_write_end->link)
 226             {
 227                 pcmbuf_write_end = pcmbuf_write_end->link;
 228                 pcmbuf_unplayed_bytes -= pcmbuf_write_end->size;
 229             }
 230             pcmbuf_flush = false;
 231         }
 232         /* If there is already a read buffer setup, add to it */
 233         else
 234             pcmbuf_read_end->link = pcmbuf_current;
 235     } else {
 236         /* Otherwise create the buffer */
 237         pcmbuf_read = pcmbuf_current;
 238     }
 239     /* This is now the last buffer to read */
 240     pcmbuf_read_end = pcmbuf_current;
 241
 242     /* Update bytes counters */
 243     pcmbuf_unplayed_bytes += size;
 244
 245     audiobuffer_pos += size;
 246     if (audiobuffer_pos >= pcmbuf_size)
 247         audiobuffer_pos -= pcmbuf_size;
 248
 249     audiobuffer_fillpos = 0;
 250 }
 251
 252 #ifdef HAVE_PRIORITY_SCHEDULING
 253 static void boost_codec_thread(bool boost)
 254 {
 255     /* Keep voice and codec threads at the same priority or else voice
 256      * will starve if the codec thread's priority is boosted. */
 257     if (boost)
 258     {
 259         if (codec_thread_priority == 0)
 260         {
 261             codec_thread_priority = thread_set_priority(
 262                 codec_thread_p, PRIORITY_REALTIME);
 263             voice_thread_set_priority(PRIORITY_REALTIME);
 264         }
 265     }
 266     else if (codec_thread_priority != 0)
 267     {
 268         thread_set_priority(codec_thread_p, codec_thread_priority);
 269         voice_thread_set_priority(codec_thread_priority);
 270         codec_thread_priority = 0;
 271     }
 272 }
 273 #endif /* HAVE_PRIORITY_SCHEDULING */
 274
 275 static void pcmbuf_under_watermark(void)
 276 {
 277     /* Only codec thread initiates boost - voice boosts the cpu when playing
 278        a clip */
 279 #ifndef SIMULATOR
 280     if (thread_get_current() == codec_thread_p)
 281 #endif /* SIMULATOR */
 282     {
 283 #ifdef HAVE_PRIORITY_SCHEDULING
 284         /* If buffer is critically low, override UI priority, else
 285            set back to the original priority. */
 286         boost_codec_thread(LOW_DATA(2) && pcm_is_playing());
 287 #endif
 288         /* Fill audio buffer by boosting cpu */
 289         trigger_cpu_boost();
 290     }
 291
 292     /* Disable crossfade if < .5s of audio */
 293     if (LOW_DATA(2))
 294     {
 295         crossfade_active = false;
 296     }
 297 }
 298
 299 void pcmbuf_set_event_handler(void (*event_handler)(void))
 300 {
 301     pcmbuf_event_handler = event_handler;
 302 }
 303
 304 unsigned int pcmbuf_get_latency(void)
 305 {
 306     /* Be careful how this calculation is rearranged, it's easy to overflow */
 307     size_t bytes = pcmbuf_unplayed_bytes + pcm_get_bytes_waiting();
 308     return bytes / 4 / (NATIVE_FREQUENCY/1000);
 309 }
 310
 311 void pcmbuf_set_low_latency(bool state)
 312 {
 313     low_latency_mode = state;
 314 }
 315
 316 bool pcmbuf_is_lowdata(void)
 317 {
 318     if (!pcm_is_playing() || pcm_is_paused() ||
 319             crossfade_init || crossfade_active)
 320         return false;
 321
 322     /* 1 seconds of buffer is low data */
 323     return LOW_DATA(4);
 324 }
 325
 326 /* Amount of bytes left in the buffer. */
 327 inline size_t pcmbuf_free(void)
 328 {
 329     if (pcmbuf_read != NULL)
 330     {
 331         void *read = pcmbuf_read->addr;
 332         void *write = &audiobuffer[audiobuffer_pos + audiobuffer_fillpos];
 333         if (read < write)
 334             return (size_t)(read - write) + pcmbuf_size;
 335         else
 336             return (size_t) (read - write);
 337     }
 338     return pcmbuf_size;
 339 }
 340
 341 bool pcmbuf_crossfade_init(bool manual_skip)
 342 {
 343     /* Can't do two crossfades at once and, no fade if pcm is off now */
 344     if (crossfade_init || crossfade_active || !pcm_is_playing())
 345     {
 346         pcmbuf_play_stop();
 347         return false;
 348     }
 349
 350     trigger_cpu_boost();
 351
 352     /* Not enough data, or crossfade disabled, flush the old data instead */
 353     if (LOW_DATA(2) || !pcmbuf_is_crossfade_enabled() || low_latency_mode)
 354     {
 355         pcmbuf_flush_fillpos();
 356         pcmbuf_flush = true;
 357         return false;
 358     }
 359
 360     /* Don't enable mix mode when skipping tracks manually. */
 361     if (manual_skip)
 362         crossfade_mixmode = false;
 363     else
 364         crossfade_mixmode = global_settings.crossfade_fade_out_mixmode;
 365
 366     crossfade_init = true;
 367
 368     return true;
 369
 370 }
 371
 372 void pcmbuf_play_stop(void)
 373 {
 374     pcm_play_stop();
 375
 376     pcmbuf_unplayed_bytes = 0;
 377     pcmbuf_mix_chunk = NULL;
 378     if (pcmbuf_read) {
 379         pcmbuf_write_end->link = pcmbuf_read;
 380         pcmbuf_write_end = pcmbuf_read_end;
 381         pcmbuf_read = pcmbuf_read_end = NULL;
 382     }
 383     audiobuffer_pos = 0;
 384     audiobuffer_fillpos = 0;
 385     crossfade_init = false;
 386     crossfade_active = false;
 387     pcmbuf_flush = false;
 388
 389 #ifdef HAVE_PRIORITY_SCHEDULING
 390     /* Can unboost the codec thread here no matter who's calling */
 391     boost_codec_thread(false);
 392 #endif
 393 }
 394
 395 int pcmbuf_used_descs(void) {
 396     struct pcmbufdesc *pcmbuf_temp = pcmbuf_read;
 397     unsigned int i = 0;
 398     while (pcmbuf_temp) {
 399         pcmbuf_temp = pcmbuf_temp->link;
 400         i++;
 401     }
 402     return i;
 403 }
 404
 405 int pcmbuf_descs(void) {
 406     return PCMBUF_DESCS(pcmbuf_size);
 407 }
 408
 409 size_t get_pcmbuf_descsize(void) {
 410     return pcmbuf_descsize;
 411 }
 412
 413 static void pcmbuf_init_pcmbuffers(void) {
 414     struct pcmbufdesc *next = pcmbuf_write;
 415     next++;
 416     pcmbuf_write_end = pcmbuf_write;
 417     while ((void *)next < (void *)pcmbuf_bufend) {
 418         pcmbuf_write_end->link=next;
 419         pcmbuf_write_end=next;
 420         next++;
 421     }
 422 }
 423
 424 static size_t pcmbuf_get_next_required_pcmbuf_size(void)
 425 {
 426 #if MEM > 1
 427     size_t seconds = 1;
 428
 429     if (crossfade_enabled_pending)
 430         seconds += global_settings.crossfade_fade_out_delay
 431                    + global_settings.crossfade_fade_out_duration;
 432
 433     /* Buffer has to be at least 2s long. */
 434     seconds += 2;
 435     logf("pcmbuf len: %ld", seconds);
 436     return seconds * (NATIVE_FREQUENCY*4);
 437 #else
 438     return NATIVE_FREQUENCY*2;
 439 #endif
 440 }
 441
 442 static char *pcmbuf_calc_audiobuffer_ptr(size_t bufsize)
 443 {
 444     return pcmbuf_bufend - (bufsize + PCMBUF_MIX_CHUNK * 2 +
 445                PCMBUF_DESCS_SIZE(bufsize));
 446 }
 447
 448 bool pcmbuf_is_same_size(void)
 449 {
 450     if (audiobuffer == NULL)
 451         return true; /* Not set up yet even once so always */
 452
 453     size_t bufsize = pcmbuf_get_next_required_pcmbuf_size();
 454     return pcmbuf_calc_audiobuffer_ptr(bufsize) == audiobuffer;
 455 }
 456
 457 /* Initialize the pcmbuffer the structure looks like this:
 458  * ...|---------PCMBUF---------|FADEBUF|VOICEBUF|DESCS|... */
 459 size_t pcmbuf_init(unsigned char *bufend)
 460 {
 461     pcmbuf_bufend = bufend;
 462     pcmbuf_size = pcmbuf_get_next_required_pcmbuf_size();
 463     audiobuffer = pcmbuf_calc_audiobuffer_ptr(pcmbuf_size);
 464     fadebuf = &audiobuffer[pcmbuf_size];
 465     voicebuf = &fadebuf[PCMBUF_MIX_CHUNK];
 466     pcmbuf_write = (struct pcmbufdesc *)&voicebuf[PCMBUF_MIX_CHUNK];
 467
 468     pcmbuf_descsize = PCMBUF_DESCS_SIZE(pcmbuf_size);
 469     pcmbuf_init_pcmbuffers();
 470
 471     position_callback = NULL;
 472     pcmbuf_event_handler = NULL;
 473
 474     pcmbuf_crossfade_enable_finished();
 475
 476     pcmbuf_play_stop();
 477
 478     return pcmbuf_bufend - audiobuffer;
 479 }
 480
 481 size_t pcmbuf_get_bufsize(void)
 482 {
 483     return pcmbuf_size;
 484 }
 485
 486 #ifdef ROCKBOX_HAS_LOGF
 487 unsigned char * pcmbuf_get_meminfo(size_t *length)
 488 {
 489     *length = pcmbuf_bufend - audiobuffer;
 490     return audiobuffer;
 491 }
 492 #endif
 493
 494 void pcmbuf_pause(bool pause)
 495 {
 496 #ifdef PCMBUF_MUTING
 497     if (pause)
 498        pcm_mute(true);
 499 #endif
 500
 501     if (pcm_is_playing())
 502         pcm_play_pause(!pause);
 503     else if (!pause)
 504         pcmbuf_play_start();
 505
 506 #ifdef PCMBUF_MUTING
 507     if (!pause)
 508         pcm_mute(false);
 509 #endif
 510     trigger_cpu_boost();
 511 }
 512
 513 /* Force playback. */
 514 void pcmbuf_play_start(void)
 515 {
 516     if (!pcm_is_playing() && pcmbuf_unplayed_bytes && pcmbuf_read != NULL)
 517     {
 518         last_chunksize = pcmbuf_read->size;
 519         pcmbuf_unplayed_bytes -= last_chunksize;
 520         pcm_play_data(pcmbuf_callback,
 521             (unsigned char *)pcmbuf_read->addr, last_chunksize);
 522     }
 523 }
 524
 525 /**
 526  * Commit samples waiting to the pcm buffer.
 527  */
 528 static bool pcmbuf_flush_fillpos(void)
 529 {
 530     if (audiobuffer_fillpos) {
 531         /* Never use the last buffer descriptor */
 532         while (pcmbuf_write == pcmbuf_write_end) {
 533             /* If this happens, something is being stupid */
 534             if (!pcm_is_playing()) {
 535                 logf("pcmbuf_flush_fillpos error");
 536                 pcmbuf_play_start();
 537             }
 538             /* Let approximately one chunk of data playback */
 539             sleep(HZ*PCMBUF_TARGET_CHUNK/(NATIVE_FREQUENCY*4));
 540         }
 541         pcmbuf_add_chunk();
 542         return true;
 543     }
 544     return false;
 545 }
 546
 547 /**
 548  * Completely process the crossfade fade out effect with current pcm buffer.
 549  */
 550 static void crossfade_process_buffer(size_t fade_in_delay,
 551         size_t fade_out_delay, size_t fade_out_rem)
 552 {
 553     if (!crossfade_mixmode)
 554     {
 555         /* Fade out the specified amount of the already processed audio */
 556         size_t total_fade_out = fade_out_rem;
 557         size_t fade_out_sample;
 558         struct pcmbufdesc *fade_out_chunk = crossfade_chunk;
 559
 560         /* Find the right chunk to start fading out */
 561         fade_out_delay += crossfade_sample * 2;
 562         while (fade_out_delay != 0 && fade_out_delay >= fade_out_chunk->size)
 563         {
 564             fade_out_delay -= fade_out_chunk->size;
 565             fade_out_chunk = fade_out_chunk->link;
 566         }
 567         /* The start sample within the chunk */
 568         fade_out_sample = fade_out_delay / 2;
 569
 570         while (fade_out_rem > 0)
 571         {
 572             /* Each 1/10 second of audio will have the same fade applied */
 573             size_t block_rem = MIN(NATIVE_FREQUENCY * 4 / 10, fade_out_rem);
 574             int factor = (fade_out_rem << 8) / total_fade_out;
 575
 576             fade_out_rem -= block_rem;
 577
 578             /* Fade this block */
 579             while (block_rem > 0 && fade_out_chunk != NULL)
 580             {
 581                 /* Fade one sample */
 582                 int16_t *buf = (int16_t *)fade_out_chunk->addr;
 583                 int32_t sample = buf[fade_out_sample];
 584                 buf[fade_out_sample++] = (sample * factor) >> 8;
 585
 586                 block_rem -= 2;
 587                 /* Move to the next chunk as needed */
 588                 if (fade_out_sample * 2 >= fade_out_chunk->size)
 589                 {
 590                     fade_out_chunk = fade_out_chunk->link;
 591                     fade_out_sample = 0;
 592                 }
 593             }
 594         }
 595     }
 596
 597     /* Find the right chunk and sample to start fading in */
 598     fade_in_delay += crossfade_sample * 2;
 599     while (fade_in_delay != 0 && fade_in_delay >= crossfade_chunk->size)
 600     {
 601         fade_in_delay -= crossfade_chunk->size;
 602         crossfade_chunk = crossfade_chunk->link;
 603     }
 604     crossfade_sample = fade_in_delay / 2;
 605     logf("process done!");
 606 }
 607
 608 /* Initializes crossfader, calculates all necessary parameters and
 609  * performs fade-out with the pcm buffer.  */
 610 static void crossfade_start(void)
 611 {
 612     size_t crossfade_rem;
 613     size_t crossfade_need;
 614     size_t fade_out_rem;
 615     size_t fade_out_delay;
 616     size_t fade_in_delay;
 617
 618     crossfade_init = false;
 619     /* Reject crossfade if less than .5s of data */
 620     if (LOW_DATA(2)) {
 621         logf("crossfade rejected");
 622         pcmbuf_play_stop();
 623         return ;
 624     }
 625
 626     logf("crossfade_start");
 627     pcmbuf_flush_fillpos();
 628     crossfade_active = true;
 629
 630     /* Initialize the crossfade buffer size to all of the buffered data that
 631      * has not yet been sent to the DMA */
 632     crossfade_rem = pcmbuf_unplayed_bytes;
 633     crossfade_chunk = pcmbuf_read->link;
 634     crossfade_sample = 0;
 635
 636     /* Get fade out delay from settings. */
 637     fade_out_delay =
 638         NATIVE_FREQUENCY * global_settings.crossfade_fade_out_delay * 4;
 639
 640     /* Get fade out duration from settings. */
 641     fade_out_rem =
 642         NATIVE_FREQUENCY * global_settings.crossfade_fade_out_duration * 4;
 643
 644     crossfade_need = fade_out_delay + fade_out_rem;
 645     /* We want only to modify the last part of the buffer. */
 646     if (crossfade_rem > crossfade_need)
 647     {
 648         size_t crossfade_extra = crossfade_rem - crossfade_need;
 649         while (crossfade_extra > crossfade_chunk->size)
 650         {
 651             crossfade_extra -= crossfade_chunk->size;
 652             crossfade_chunk = crossfade_chunk->link;
 653         }
 654         crossfade_sample = crossfade_extra / 2;
 655     }
 656     /* Truncate fade out duration if necessary. */
 657     else if (crossfade_rem < crossfade_need)
 658     {
 659         size_t crossfade_short = crossfade_need - crossfade_rem;
 660         if (fade_out_rem >= crossfade_short)
 661             fade_out_rem -= crossfade_short;
 662         else
 663         {
 664             fade_out_delay -= crossfade_short - fade_out_rem;
 665             fade_out_rem = 0;
 666         }
 667     }
 668
 669     /* Get also fade in duration and delays from settings. */
 670     crossfade_fade_in_total =
 671         NATIVE_FREQUENCY * global_settings.crossfade_fade_in_duration * 4;
 672     crossfade_fade_in_rem = crossfade_fade_in_total;
 673
 674     fade_in_delay =
 675         NATIVE_FREQUENCY * global_settings.crossfade_fade_in_delay * 4;
 676
 677     crossfade_process_buffer(fade_in_delay, fade_out_delay, fade_out_rem);
 678 }
 679
 680 /* Returns the number of bytes _NOT_ mixed */
 681 static size_t crossfade_fade_mix(int factor, const char *buf, size_t fade_rem)
 682 {
 683     const int16_t *input_buf = (const int16_t *)buf;
 684     int16_t *output_buf = (int16_t *)(crossfade_chunk->addr);
 685     int16_t *chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 686     output_buf = &output_buf[crossfade_sample];
 687
 688     while (fade_rem)
 689     {
 690         int32_t sample = *input_buf++;
 691         sample = ((sample * factor) >> 8) + *output_buf;
 692         *output_buf++ = clip_sample_16(sample);
 693         fade_rem -= 2;
 694
 695         if (output_buf >= chunk_end)
 696         {
 697             crossfade_chunk = crossfade_chunk->link;
 698             if (!crossfade_chunk)
 699                 return fade_rem;
 700             output_buf = (int16_t *)crossfade_chunk->addr;
 701             chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 702         }
 703     }
 704     crossfade_sample = output_buf - (int16_t *)crossfade_chunk->addr;
 705     return 0;
 706 }
 707
 708 /* Returns the number of bytes _NOT_ mixed */
 709 static size_t crossfade_mix(const char *buf, size_t length)
 710 {
 711     const int16_t *input_buf = (const int16_t *)buf;
 712     int16_t *output_buf = (int16_t *)crossfade_chunk->addr;
 713     int16_t *chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 714     output_buf = &output_buf[crossfade_sample];
 715
 716     while (length)
 717     {
 718         int32_t sample = *input_buf++ + *output_buf;
 719         *output_buf++ = clip_sample_16(sample);
 720         length -= 2;
 721
 722         if (output_buf >= chunk_end)
 723         {
 724             crossfade_chunk = crossfade_chunk->link;
 725             if (!crossfade_chunk)
 726                 return length;
 727
 728             output_buf = (int16_t *)crossfade_chunk->addr;
 729             chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 730         }
 731     }
 732     crossfade_sample = output_buf - (int16_t *)crossfade_chunk->addr;
 733     return 0;
 734 }
 735
 736 static void pcmbuf_flush_buffer(const char *buf, size_t length)
 737 {
 738     size_t copy_n;
 739     while (length > 0) {
 740         size_t audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 741         if (NEED_FLUSH(audiobuffer_index))
 742         {
 743             pcmbuf_flush_fillpos();
 744             audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 745         }
 746         copy_n = MIN(length, pcmbuf_size - audiobuffer_index);
 747         memcpy(&audiobuffer[audiobuffer_index], buf, copy_n);
 748         buf += copy_n;
 749         audiobuffer_fillpos += copy_n;
 750         length -= copy_n;
 751     }
 752 }
 753
 754 static void flush_crossfade(char *buf, size_t length)
 755 {
 756     if (length)
 757     {
 758         if (crossfade_fade_in_rem)
 759         {
 760             size_t samples;
 761             int16_t *input_buf;
 762
 763             /* Fade factor for this packet */
 764             int factor =
 765                 ((crossfade_fade_in_total - crossfade_fade_in_rem) << 8) /
 766                 crossfade_fade_in_total;
 767             /* Bytes to fade */
 768             size_t fade_rem = MIN(length, crossfade_fade_in_rem);
 769
 770             /* We _will_ fade this many bytes */
 771             crossfade_fade_in_rem -= fade_rem;
 772
 773             if (crossfade_chunk)
 774             {
 775                 /* Mix the data */
 776                 size_t fade_total = fade_rem;
 777                 fade_rem = crossfade_fade_mix(factor, buf, fade_rem);
 778                 length -= fade_total - fade_rem;
 779                 buf += fade_total - fade_rem;
 780                 if (!length)
 781                     return;
 782                 if (!fade_rem)
 783                     goto fade_done;
 784             }
 785
 786             samples = fade_rem / 2;
 787             input_buf = (int16_t *)buf;
 788             /* Fade remaining samples in place */
 789             while (samples)
 790             {
 791                 int32_t sample = *input_buf;
 792                 *input_buf++ = (sample * factor) >> 8;
 793                 samples--;
 794             }
 795         }
 796
 797 fade_done:
 798         if (crossfade_chunk)
 799         {
 800             /* Mix the data */
 801             size_t mix_total = length;
 802             length = crossfade_mix(buf, length);
 803             buf += mix_total - length;
 804             if (!length)
 805                 return;
 806         }
 807
 808         /* Flush samples to the buffer */
 809         while (!prepare_insert(length))
 810             sleep(1);
 811         pcmbuf_flush_buffer(buf, length);
 812     }
 813
 814 }
 815
 816 static bool prepare_insert(size_t length)
 817 {
 818     if (low_latency_mode)
 819     {
 820         /* 1/4s latency. */
 821         if (pcmbuf_unplayed_bytes > NATIVE_FREQUENCY * 4 / 4
 822             && pcm_is_playing())
 823             return false;
 824     }
 825
 826     /* Need to save PCMBUF_MIN_CHUNK to prevent wrapping overwriting */
 827     if (pcmbuf_free() < length + PCMBUF_MIN_CHUNK)
 828         return false;
 829
 830     if (!pcm_is_playing())
 831     {
 832         trigger_cpu_boost();
 833
 834         /* Pre-buffer 1s. */
 835 #if MEM <= 1
 836         if (!LOW_DATA(1))
 837 #else
 838         if (!LOW_DATA(4))
 839 #endif
 840         {
 841             logf("pcm starting");
 842             if (!(audio_status() & AUDIO_STATUS_PAUSE))
 843                 pcmbuf_play_start();
 844         }
 845     }
 846     else if (pcmbuf_unplayed_bytes <= pcmbuf_watermark)
 847         pcmbuf_under_watermark();
 848
 849     return true;
 850 }
 851
 852 void* pcmbuf_request_buffer(int *count)
 853 {
 854     if (crossfade_init)
 855         crossfade_start();
 856
 857     if (crossfade_active) {
 858         *count = MIN(*count, PCMBUF_MIX_CHUNK/4);
 859         return fadebuf;
 860     }
 861     else
 862     {
 863         if(prepare_insert(*count << 2))
 864         {
 865             size_t audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 866             if (pcmbuf_size - audiobuffer_index >= PCMBUF_MIN_CHUNK)
 867             {
 868                 /* Usual case, there's space here */
 869                 return &audiobuffer[audiobuffer_index];
 870             }
 871             else
 872             {
 873                 /* Flush and wrap the buffer */
 874                 pcmbuf_flush_fillpos();
 875                 audiobuffer_pos = 0;
 876                 return &audiobuffer[0];
 877             }
 878         }
 879         else
 880         {
 881             return NULL;
 882         }
 883     }
 884 }
 885
 886 void * pcmbuf_request_voice_buffer(int *count)
 887 {
 888     /* A get-it-to-work-for-now hack (audio status could change by
 889        completion) */
 890     if (audio_status() & AUDIO_STATUS_PLAY)
 891     {
 892         if (pcmbuf_read == NULL)
 893         {
 894             return NULL;
 895         }
 896         else if (pcmbuf_usage() >= 10 && pcmbuf_mix_free() >= 30 &&
 897                  (pcmbuf_mix_chunk || pcmbuf_read->link))
 898         {
 899             *count = MIN(*count, PCMBUF_MIX_CHUNK/4);
 900             return voicebuf;
 901         }
 902         else
 903         {
 904             return NULL;
 905         }
 906     }
 907     else
 908     {
 909         return pcmbuf_request_buffer(count);
 910     }
 911 }
 912
 913 bool pcmbuf_is_crossfade_active(void)
 914 {
 915     return crossfade_active || crossfade_init;
 916 }
 917
 918 void pcmbuf_write_complete(int count)
 919 {
 920     size_t length = (size_t)(unsigned int)count << 2;
 921
 922     if (crossfade_active)
 923     {
 924         flush_crossfade(fadebuf, length);
 925         if (!(crossfade_fade_in_rem || crossfade_chunk))
 926             crossfade_active = false;
 927     }
 928     else
 929     {
 930         audiobuffer_fillpos += length;
 931
 932         if (NEED_FLUSH(audiobuffer_pos + audiobuffer_fillpos))
 933             pcmbuf_flush_fillpos();
 934     }
 935 }
 936
 937 #if 0
 938 bool pcmbuf_insert_buffer(char *buf, int count)
 939 {
 940     size_t length = (size_t)(unsigned int)count << 2;
 941
 942     if (crossfade_active)
 943     {
 944         flush_crossfade(buf, length);
 945         if (!(crossfade_fade_in_rem || crossfade_chunk))
 946             crossfade_active = false;
 947     }
 948     else
 949     {
 950         if (!prepare_insert(length))
 951             return false;
 952         pcmbuf_flush_buffer(buf, length);
 953     }
 954     return true;
 955 }
 956 #endif
 957
 958 /* Generates a constant square wave sound with a given frequency
 959    in Hertz for a duration in milliseconds. */
 960 void pcmbuf_beep(unsigned int frequency, size_t duration, int amplitude)
 961 {
 962     unsigned int count = 0, i = 0;
 963     unsigned int interval = NATIVE_FREQUENCY / frequency;
 964     int32_t sample;
 965     int16_t *buf;
 966     int16_t *pcmbuf_end = (int16_t *)fadebuf;
 967     size_t samples = NATIVE_FREQUENCY / 1000 * duration;
 968
 969     if (pcm_is_playing() && pcmbuf_read != NULL)
 970     {
 971         if (pcmbuf_read->link)
 972         {
 973             /* Get the next chunk */
 974             char *pcmbuf_mix_buf = pcmbuf_read->link->addr;
 975             /* Give at least 1/8s clearance. */
 976             buf = (int16_t *)&pcmbuf_mix_buf[NATIVE_FREQUENCY * 4 / 8];
 977         }
 978         else
 979         {
 980             logf("No place to beep");
 981             return;
 982         }
 983
 984         while (i++ < samples)
 985         {
 986             sample = *buf;
 987             *buf++ = clip_sample_16(sample + amplitude);
 988             if (buf > pcmbuf_end)
 989                 buf = (int16_t *)audiobuffer;
 990             sample = *buf;
 991             *buf++ = clip_sample_16(sample + amplitude);
 992
 993             /* Toggle square wav side */
 994             if (++count >= interval)
 995             {
 996                 count = 0;
 997                 amplitude = -amplitude;
 998             }
 999             if (buf > pcmbuf_end)
1000                 buf = (int16_t *)audiobuffer;
1001         }
1002     }
1003     else
1004     {
1005         buf = (int16_t *)audiobuffer;
1006         while (i++ < samples)
1007         {
1008             *buf++ = amplitude;
1009             if (buf > pcmbuf_end)
1010                 buf = (int16_t *)audiobuffer;
1011             *buf++ = amplitude;
1012
1013             /* Toggle square wav side */
1014             if (++count >= interval)
1015             {
1016                 count = 0;
1017                 amplitude = -amplitude;
1018             }
1019             if (buf > pcmbuf_end)
1020                 buf = (int16_t *)audiobuffer;
1021         }
1022         pcm_play_data(NULL, (unsigned char *)audiobuffer, samples * 4);
1023     }
1024 }
1025
1026 /* Returns pcm buffer usage in percents (0 to 100). */
1027 int pcmbuf_usage(void)
1028 {
1029     return pcmbuf_unplayed_bytes * 100 / pcmbuf_size;
1030 }
1031
1032 int pcmbuf_mix_free(void)
1033 {
1034     if (pcmbuf_mix_chunk)
1035     {
1036         size_t my_mix_end =
1037             (size_t)&((int16_t *)pcmbuf_mix_chunk->addr)[pcmbuf_mix_sample];
1038         size_t my_write_pos = (size_t)&audiobuffer[audiobuffer_pos];
1039         if (my_write_pos < my_mix_end)
1040             my_write_pos += pcmbuf_size;
1041         return (my_write_pos - my_mix_end) * 100 / pcmbuf_unplayed_bytes;
1042     }
1043     return 100;
1044 }
1045
1046 void pcmbuf_write_voice_complete(int count)
1047 {
1048     /* A get-it-to-work-for-now hack (audio status could have changed) */
1049     if (!(audio_status() & AUDIO_STATUS_PLAY))
1050     {
1051         pcmbuf_write_complete(count);
1052         return;
1053     }
1054
1055     int16_t *ibuf = (int16_t *)voicebuf;
1056     int16_t *obuf;
1057     size_t chunk_samples;
1058
1059     if (pcmbuf_mix_chunk == NULL && pcmbuf_read != NULL)
1060     {
1061         pcmbuf_mix_chunk = pcmbuf_read->link;
1062         /* Start 1/8s into the next chunk */
1063         pcmbuf_mix_sample = NATIVE_FREQUENCY * 4 / 16;
1064     }
1065
1066     if (!pcmbuf_mix_chunk)
1067         return;
1068
1069     obuf = (int16_t *)pcmbuf_mix_chunk->addr;
1070     chunk_samples = pcmbuf_mix_chunk->size / sizeof (int16_t);
1071
1072     count <<= 1;
1073
1074     while (count-- > 0)
1075     {
1076         int32_t sample = *ibuf++;
1077
1078         if (pcmbuf_mix_sample >= chunk_samples)
1079         {
1080             pcmbuf_mix_chunk = pcmbuf_mix_chunk->link;
1081             if (!pcmbuf_mix_chunk)
1082                 return;
1083             pcmbuf_mix_sample = 0;
1084             obuf = pcmbuf_mix_chunk->addr;
1085             chunk_samples = pcmbuf_mix_chunk->size / 2;
1086         }
1087         sample += obuf[pcmbuf_mix_sample] >> 2;
1088         obuf[pcmbuf_mix_sample++] = clip_sample_16(sample);
1089     }
1090 }
1091
1092 void pcmbuf_crossfade_enable(bool on_off)
1093 {
1094 #if MEM > 1
1095     /* Next setting to be used, not applied now */
1096     crossfade_enabled_pending = on_off;
1097 #endif
1098     (void)on_off;
1099 }
1100
1101 void pcmbuf_crossfade_enable_finished(void)
1102 {
1103     /* Copy the pending setting over now */
1104     crossfade_enabled = crossfade_enabled_pending;
1105     pcmbuf_set_watermark_bytes();
1106 }
1107
1108 bool pcmbuf_is_crossfade_enabled(void)
1109 {
1110     if (global_settings.crossfade == CROSSFADE_ENABLE_SHUFFLE)
1111         return global_settings.playlist_shuffle;
1112
1113     return crossfade_enabled;
1114 }