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 = PRIORITY_PLAYBACK;
 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         int priority = (PRIORITY_PLAYBACK - PRIORITY_PLAYBACK_MAX)*pcmbuf_unplayed_bytes
 260                           / (2*NATIVE_FREQUENCY) + PRIORITY_PLAYBACK_MAX;
 261
 262         if (priority != codec_thread_priority)
 263         {
 264             codec_thread_priority = priority;
 265             thread_set_priority(codec_thread_p, priority);
 266             voice_thread_set_priority(priority);
 267         }
 268     }
 269     else if (codec_thread_priority != PRIORITY_PLAYBACK)
 270     {
 271         thread_set_priority(codec_thread_p, PRIORITY_PLAYBACK);
 272         voice_thread_set_priority(PRIORITY_PLAYBACK);
 273         codec_thread_priority = PRIORITY_PLAYBACK;
 274     }
 275 }
 276 #endif /* HAVE_PRIORITY_SCHEDULING */
 277
 278 static void pcmbuf_under_watermark(void)
 279 {
 280     /* Only codec thread initiates boost - voice boosts the cpu when playing
 281        a clip */
 282 #ifndef SIMULATOR
 283     if (thread_get_current() == codec_thread_p)
 284 #endif /* SIMULATOR */
 285     {
 286 #ifdef HAVE_PRIORITY_SCHEDULING
 287         /* If buffer is critically low, override UI priority, else
 288            set back to the original priority. */
 289         boost_codec_thread(LOW_DATA(2) && pcm_is_playing());
 290 #endif
 291         /* Fill audio buffer by boosting cpu */
 292         trigger_cpu_boost();
 293     }
 294
 295     /* Disable crossfade if < .5s of audio */
 296     if (LOW_DATA(2))
 297     {
 298         crossfade_active = false;
 299     }
 300 }
 301
 302 void pcmbuf_set_event_handler(void (*event_handler)(void))
 303 {
 304     pcmbuf_event_handler = event_handler;
 305 }
 306
 307 unsigned int pcmbuf_get_latency(void)
 308 {
 309     /* Be careful how this calculation is rearranged, it's easy to overflow */
 310     size_t bytes = pcmbuf_unplayed_bytes + pcm_get_bytes_waiting();
 311     return bytes / 4 / (NATIVE_FREQUENCY/1000);
 312 }
 313
 314 void pcmbuf_set_low_latency(bool state)
 315 {
 316     low_latency_mode = state;
 317 }
 318
 319 bool pcmbuf_is_lowdata(void)
 320 {
 321     if (!pcm_is_playing() || pcm_is_paused() ||
 322             crossfade_init || crossfade_active)
 323         return false;
 324
 325     /* 1 seconds of buffer is low data */
 326     return LOW_DATA(4);
 327 }
 328
 329 /* Amount of bytes left in the buffer. */
 330 inline size_t pcmbuf_free(void)
 331 {
 332     if (pcmbuf_read != NULL)
 333     {
 334         void *read = pcmbuf_read->addr;
 335         void *write = &audiobuffer[audiobuffer_pos + audiobuffer_fillpos];
 336         if (read < write)
 337             return (size_t)(read - write) + pcmbuf_size;
 338         else
 339             return (size_t) (read - write);
 340     }
 341     return pcmbuf_size;
 342 }
 343
 344 bool pcmbuf_crossfade_init(bool manual_skip)
 345 {
 346     /* Can't do two crossfades at once and, no fade if pcm is off now */
 347     if (crossfade_init || crossfade_active || !pcm_is_playing())
 348     {
 349         pcmbuf_play_stop();
 350         return false;
 351     }
 352
 353     trigger_cpu_boost();
 354
 355     /* Not enough data, or crossfade disabled, flush the old data instead */
 356     if (LOW_DATA(2) || !pcmbuf_is_crossfade_enabled() || low_latency_mode)
 357     {
 358         pcmbuf_flush_fillpos();
 359         pcmbuf_flush = true;
 360         return false;
 361     }
 362
 363     /* Don't enable mix mode when skipping tracks manually. */
 364     if (manual_skip)
 365         crossfade_mixmode = false;
 366     else
 367         crossfade_mixmode = global_settings.crossfade_fade_out_mixmode;
 368
 369     crossfade_init = true;
 370
 371     return true;
 372
 373 }
 374
 375 void pcmbuf_play_stop(void)
 376 {
 377     pcm_play_stop();
 378
 379     pcmbuf_unplayed_bytes = 0;
 380     pcmbuf_mix_chunk = NULL;
 381     if (pcmbuf_read) {
 382         pcmbuf_write_end->link = pcmbuf_read;
 383         pcmbuf_write_end = pcmbuf_read_end;
 384         pcmbuf_read = pcmbuf_read_end = NULL;
 385     }
 386     audiobuffer_pos = 0;
 387     audiobuffer_fillpos = 0;
 388     crossfade_init = false;
 389     crossfade_active = false;
 390     pcmbuf_flush = false;
 391
 392 #ifdef HAVE_PRIORITY_SCHEDULING
 393     /* Can unboost the codec thread here no matter who's calling */
 394     boost_codec_thread(false);
 395 #endif
 396 }
 397
 398 int pcmbuf_used_descs(void) {
 399     struct pcmbufdesc *pcmbuf_temp = pcmbuf_read;
 400     unsigned int i = 0;
 401     while (pcmbuf_temp) {
 402         pcmbuf_temp = pcmbuf_temp->link;
 403         i++;
 404     }
 405     return i;
 406 }
 407
 408 int pcmbuf_descs(void) {
 409     return PCMBUF_DESCS(pcmbuf_size);
 410 }
 411
 412 size_t get_pcmbuf_descsize(void) {
 413     return pcmbuf_descsize;
 414 }
 415
 416 static void pcmbuf_init_pcmbuffers(void) {
 417     struct pcmbufdesc *next = pcmbuf_write;
 418     next++;
 419     pcmbuf_write_end = pcmbuf_write;
 420     while ((void *)next < (void *)pcmbuf_bufend) {
 421         pcmbuf_write_end->link=next;
 422         pcmbuf_write_end=next;
 423         next++;
 424     }
 425 }
 426
 427 static size_t pcmbuf_get_next_required_pcmbuf_size(void)
 428 {
 429 #if MEM > 1
 430     size_t seconds = 1;
 431
 432     if (crossfade_enabled_pending)
 433         seconds += global_settings.crossfade_fade_out_delay
 434                    + global_settings.crossfade_fade_out_duration;
 435
 436     /* Buffer has to be at least 2s long. */
 437     seconds += 2;
 438     logf("pcmbuf len: %ld", seconds);
 439     return seconds * (NATIVE_FREQUENCY*4);
 440 #else
 441     return NATIVE_FREQUENCY*2;
 442 #endif
 443 }
 444
 445 static char *pcmbuf_calc_audiobuffer_ptr(size_t bufsize)
 446 {
 447     return pcmbuf_bufend - (bufsize + PCMBUF_MIX_CHUNK * 2 +
 448                PCMBUF_DESCS_SIZE(bufsize));
 449 }
 450
 451 bool pcmbuf_is_same_size(void)
 452 {
 453     if (audiobuffer == NULL)
 454         return true; /* Not set up yet even once so always */
 455
 456     size_t bufsize = pcmbuf_get_next_required_pcmbuf_size();
 457     return pcmbuf_calc_audiobuffer_ptr(bufsize) == audiobuffer;
 458 }
 459
 460 /* Initialize the pcmbuffer the structure looks like this:
 461  * ...|---------PCMBUF---------|FADEBUF|VOICEBUF|DESCS|... */
 462 size_t pcmbuf_init(unsigned char *bufend)
 463 {
 464     pcmbuf_bufend = bufend;
 465     pcmbuf_size = pcmbuf_get_next_required_pcmbuf_size();
 466     audiobuffer = pcmbuf_calc_audiobuffer_ptr(pcmbuf_size);
 467     fadebuf = &audiobuffer[pcmbuf_size];
 468     voicebuf = &fadebuf[PCMBUF_MIX_CHUNK];
 469     pcmbuf_write = (struct pcmbufdesc *)&voicebuf[PCMBUF_MIX_CHUNK];
 470
 471     pcmbuf_descsize = PCMBUF_DESCS_SIZE(pcmbuf_size);
 472     pcmbuf_init_pcmbuffers();
 473
 474     position_callback = NULL;
 475     pcmbuf_event_handler = NULL;
 476
 477     pcmbuf_crossfade_enable_finished();
 478
 479     pcmbuf_play_stop();
 480
 481     return pcmbuf_bufend - audiobuffer;
 482 }
 483
 484 size_t pcmbuf_get_bufsize(void)
 485 {
 486     return pcmbuf_size;
 487 }
 488
 489 #ifdef ROCKBOX_HAS_LOGF
 490 unsigned char * pcmbuf_get_meminfo(size_t *length)
 491 {
 492     *length = pcmbuf_bufend - audiobuffer;
 493     return audiobuffer;
 494 }
 495 #endif
 496
 497 void pcmbuf_pause(bool pause)
 498 {
 499 #ifdef PCMBUF_MUTING
 500     if (pause)
 501        pcm_mute(true);
 502 #endif
 503
 504     if (pcm_is_playing())
 505         pcm_play_pause(!pause);
 506     else if (!pause)
 507         pcmbuf_play_start();
 508
 509 #ifdef PCMBUF_MUTING
 510     if (!pause)
 511         pcm_mute(false);
 512 #endif
 513     trigger_cpu_boost();
 514 }
 515
 516 /* Force playback. */
 517 void pcmbuf_play_start(void)
 518 {
 519     if (!pcm_is_playing() && pcmbuf_unplayed_bytes && pcmbuf_read != NULL)
 520     {
 521         last_chunksize = pcmbuf_read->size;
 522         pcmbuf_unplayed_bytes -= last_chunksize;
 523         pcm_play_data(pcmbuf_callback,
 524             (unsigned char *)pcmbuf_read->addr, last_chunksize);
 525     }
 526 }
 527
 528 /**
 529  * Commit samples waiting to the pcm buffer.
 530  */
 531 static bool pcmbuf_flush_fillpos(void)
 532 {
 533     if (audiobuffer_fillpos) {
 534         /* Never use the last buffer descriptor */
 535         while (pcmbuf_write == pcmbuf_write_end) {
 536             /* If this happens, something is being stupid */
 537             if (!pcm_is_playing()) {
 538                 logf("pcmbuf_flush_fillpos error");
 539                 pcmbuf_play_start();
 540             }
 541             /* Let approximately one chunk of data playback */
 542             sleep(HZ*PCMBUF_TARGET_CHUNK/(NATIVE_FREQUENCY*4));
 543         }
 544         pcmbuf_add_chunk();
 545         return true;
 546     }
 547     return false;
 548 }
 549
 550 /**
 551  * Completely process the crossfade fade out effect with current pcm buffer.
 552  */
 553 static void crossfade_process_buffer(size_t fade_in_delay,
 554         size_t fade_out_delay, size_t fade_out_rem)
 555 {
 556     if (!crossfade_mixmode)
 557     {
 558         /* Fade out the specified amount of the already processed audio */
 559         size_t total_fade_out = fade_out_rem;
 560         size_t fade_out_sample;
 561         struct pcmbufdesc *fade_out_chunk = crossfade_chunk;
 562
 563         /* Find the right chunk to start fading out */
 564         fade_out_delay += crossfade_sample * 2;
 565         while (fade_out_delay != 0 && fade_out_delay >= fade_out_chunk->size)
 566         {
 567             fade_out_delay -= fade_out_chunk->size;
 568             fade_out_chunk = fade_out_chunk->link;
 569         }
 570         /* The start sample within the chunk */
 571         fade_out_sample = fade_out_delay / 2;
 572
 573         while (fade_out_rem > 0)
 574         {
 575             /* Each 1/10 second of audio will have the same fade applied */
 576             size_t block_rem = MIN(NATIVE_FREQUENCY * 4 / 10, fade_out_rem);
 577             int factor = (fade_out_rem << 8) / total_fade_out;
 578
 579             fade_out_rem -= block_rem;
 580
 581             /* Fade this block */
 582             while (block_rem > 0 && fade_out_chunk != NULL)
 583             {
 584                 /* Fade one sample */
 585                 int16_t *buf = (int16_t *)fade_out_chunk->addr;
 586                 int32_t sample = buf[fade_out_sample];
 587                 buf[fade_out_sample++] = (sample * factor) >> 8;
 588
 589                 block_rem -= 2;
 590                 /* Move to the next chunk as needed */
 591                 if (fade_out_sample * 2 >= fade_out_chunk->size)
 592                 {
 593                     fade_out_chunk = fade_out_chunk->link;
 594                     fade_out_sample = 0;
 595                 }
 596             }
 597         }
 598     }
 599
 600     /* Find the right chunk and sample to start fading in */
 601     fade_in_delay += crossfade_sample * 2;
 602     while (fade_in_delay != 0 && fade_in_delay >= crossfade_chunk->size)
 603     {
 604         fade_in_delay -= crossfade_chunk->size;
 605         crossfade_chunk = crossfade_chunk->link;
 606     }
 607     crossfade_sample = fade_in_delay / 2;
 608     logf("process done!");
 609 }
 610
 611 /* Initializes crossfader, calculates all necessary parameters and
 612  * performs fade-out with the pcm buffer.  */
 613 static void crossfade_start(void)
 614 {
 615     size_t crossfade_rem;
 616     size_t crossfade_need;
 617     size_t fade_out_rem;
 618     size_t fade_out_delay;
 619     size_t fade_in_delay;
 620
 621     crossfade_init = false;
 622     /* Reject crossfade if less than .5s of data */
 623     if (LOW_DATA(2)) {
 624         logf("crossfade rejected");
 625         pcmbuf_play_stop();
 626         return ;
 627     }
 628
 629     logf("crossfade_start");
 630     pcmbuf_flush_fillpos();
 631     crossfade_active = true;
 632
 633     /* Initialize the crossfade buffer size to all of the buffered data that
 634      * has not yet been sent to the DMA */
 635     crossfade_rem = pcmbuf_unplayed_bytes;
 636     crossfade_chunk = pcmbuf_read->link;
 637     crossfade_sample = 0;
 638
 639     /* Get fade out delay from settings. */
 640     fade_out_delay =
 641         NATIVE_FREQUENCY * global_settings.crossfade_fade_out_delay * 4;
 642
 643     /* Get fade out duration from settings. */
 644     fade_out_rem =
 645         NATIVE_FREQUENCY * global_settings.crossfade_fade_out_duration * 4;
 646
 647     crossfade_need = fade_out_delay + fade_out_rem;
 648     /* We want only to modify the last part of the buffer. */
 649     if (crossfade_rem > crossfade_need)
 650     {
 651         size_t crossfade_extra = crossfade_rem - crossfade_need;
 652         while (crossfade_extra > crossfade_chunk->size)
 653         {
 654             crossfade_extra -= crossfade_chunk->size;
 655             crossfade_chunk = crossfade_chunk->link;
 656         }
 657         crossfade_sample = crossfade_extra / 2;
 658     }
 659     /* Truncate fade out duration if necessary. */
 660     else if (crossfade_rem < crossfade_need)
 661     {
 662         size_t crossfade_short = crossfade_need - crossfade_rem;
 663         if (fade_out_rem >= crossfade_short)
 664             fade_out_rem -= crossfade_short;
 665         else
 666         {
 667             fade_out_delay -= crossfade_short - fade_out_rem;
 668             fade_out_rem = 0;
 669         }
 670     }
 671
 672     /* Get also fade in duration and delays from settings. */
 673     crossfade_fade_in_total =
 674         NATIVE_FREQUENCY * global_settings.crossfade_fade_in_duration * 4;
 675     crossfade_fade_in_rem = crossfade_fade_in_total;
 676
 677     fade_in_delay =
 678         NATIVE_FREQUENCY * global_settings.crossfade_fade_in_delay * 4;
 679
 680     crossfade_process_buffer(fade_in_delay, fade_out_delay, fade_out_rem);
 681 }
 682
 683 /* Returns the number of bytes _NOT_ mixed */
 684 static size_t crossfade_fade_mix(int factor, const char *buf, size_t fade_rem)
 685 {
 686     const int16_t *input_buf = (const int16_t *)buf;
 687     int16_t *output_buf = (int16_t *)(crossfade_chunk->addr);
 688     int16_t *chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 689     output_buf = &output_buf[crossfade_sample];
 690
 691     while (fade_rem)
 692     {
 693         int32_t sample = *input_buf++;
 694         sample = ((sample * factor) >> 8) + *output_buf;
 695         *output_buf++ = clip_sample_16(sample);
 696         fade_rem -= 2;
 697
 698         if (output_buf >= chunk_end)
 699         {
 700             crossfade_chunk = crossfade_chunk->link;
 701             if (!crossfade_chunk)
 702                 return fade_rem;
 703             output_buf = (int16_t *)crossfade_chunk->addr;
 704             chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 705         }
 706     }
 707     crossfade_sample = output_buf - (int16_t *)crossfade_chunk->addr;
 708     return 0;
 709 }
 710
 711 /* Returns the number of bytes _NOT_ mixed */
 712 static size_t crossfade_mix(const char *buf, size_t length)
 713 {
 714     const int16_t *input_buf = (const int16_t *)buf;
 715     int16_t *output_buf = (int16_t *)crossfade_chunk->addr;
 716     int16_t *chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 717     output_buf = &output_buf[crossfade_sample];
 718
 719     while (length)
 720     {
 721         int32_t sample = *input_buf++ + *output_buf;
 722         *output_buf++ = clip_sample_16(sample);
 723         length -= 2;
 724
 725         if (output_buf >= chunk_end)
 726         {
 727             crossfade_chunk = crossfade_chunk->link;
 728             if (!crossfade_chunk)
 729                 return length;
 730
 731             output_buf = (int16_t *)crossfade_chunk->addr;
 732             chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 733         }
 734     }
 735     crossfade_sample = output_buf - (int16_t *)crossfade_chunk->addr;
 736     return 0;
 737 }
 738
 739 static void pcmbuf_flush_buffer(const char *buf, size_t length)
 740 {
 741     size_t copy_n;
 742     while (length > 0) {
 743         size_t audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 744         if (NEED_FLUSH(audiobuffer_index))
 745         {
 746             pcmbuf_flush_fillpos();
 747             audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 748         }
 749         copy_n = MIN(length, pcmbuf_size - audiobuffer_index);
 750         memcpy(&audiobuffer[audiobuffer_index], buf, copy_n);
 751         buf += copy_n;
 752         audiobuffer_fillpos += copy_n;
 753         length -= copy_n;
 754     }
 755 }
 756
 757 static void flush_crossfade(char *buf, size_t length)
 758 {
 759     if (length)
 760     {
 761         if (crossfade_fade_in_rem)
 762         {
 763             size_t samples;
 764             int16_t *input_buf;
 765
 766             /* Fade factor for this packet */
 767             int factor =
 768                 ((crossfade_fade_in_total - crossfade_fade_in_rem) << 8) /
 769                 crossfade_fade_in_total;
 770             /* Bytes to fade */
 771             size_t fade_rem = MIN(length, crossfade_fade_in_rem);
 772
 773             /* We _will_ fade this many bytes */
 774             crossfade_fade_in_rem -= fade_rem;
 775
 776             if (crossfade_chunk)
 777             {
 778                 /* Mix the data */
 779                 size_t fade_total = fade_rem;
 780                 fade_rem = crossfade_fade_mix(factor, buf, fade_rem);
 781                 length -= fade_total - fade_rem;
 782                 buf += fade_total - fade_rem;
 783                 if (!length)
 784                     return;
 785                 if (!fade_rem)
 786                     goto fade_done;
 787             }
 788
 789             samples = fade_rem / 2;
 790             input_buf = (int16_t *)buf;
 791             /* Fade remaining samples in place */
 792             while (samples)
 793             {
 794                 int32_t sample = *input_buf;
 795                 *input_buf++ = (sample * factor) >> 8;
 796                 samples--;
 797             }
 798         }
 799
 800 fade_done:
 801         if (crossfade_chunk)
 802         {
 803             /* Mix the data */
 804             size_t mix_total = length;
 805             length = crossfade_mix(buf, length);
 806             buf += mix_total - length;
 807             if (!length)
 808                 return;
 809         }
 810
 811         /* Flush samples to the buffer */
 812         while (!prepare_insert(length))
 813             sleep(1);
 814         pcmbuf_flush_buffer(buf, length);
 815     }
 816
 817 }
 818
 819 static bool prepare_insert(size_t length)
 820 {
 821     if (low_latency_mode)
 822     {
 823         /* 1/4s latency. */
 824         if (pcmbuf_unplayed_bytes > NATIVE_FREQUENCY * 4 / 2
 825             && pcm_is_playing())
 826             return false;
 827     }
 828
 829     /* Need to save PCMBUF_MIN_CHUNK to prevent wrapping overwriting */
 830     if (pcmbuf_free() < length + PCMBUF_MIN_CHUNK)
 831         return false;
 832
 833     if (!pcm_is_playing())
 834     {
 835         trigger_cpu_boost();
 836
 837         /* Pre-buffer 1s. */
 838 #if MEM <= 1
 839         if (!LOW_DATA(1))
 840 #else
 841         if (!LOW_DATA(4))
 842 #endif
 843         {
 844             logf("pcm starting");
 845             if (!(audio_status() & AUDIO_STATUS_PAUSE))
 846                 pcmbuf_play_start();
 847         }
 848     }
 849     else if (pcmbuf_unplayed_bytes <= pcmbuf_watermark)
 850         pcmbuf_under_watermark();
 851
 852     return true;
 853 }
 854
 855 void* pcmbuf_request_buffer(int *count)
 856 {
 857     if (crossfade_init)
 858         crossfade_start();
 859
 860     if (crossfade_active) {
 861         *count = MIN(*count, PCMBUF_MIX_CHUNK/4);
 862         return fadebuf;
 863     }
 864     else
 865     {
 866         if(prepare_insert(*count << 2))
 867         {
 868             size_t audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 869             if (pcmbuf_size - audiobuffer_index >= PCMBUF_MIN_CHUNK)
 870             {
 871                 /* Usual case, there's space here */
 872                 return &audiobuffer[audiobuffer_index];
 873             }
 874             else
 875             {
 876                 /* Flush and wrap the buffer */
 877                 pcmbuf_flush_fillpos();
 878                 audiobuffer_pos = 0;
 879                 return &audiobuffer[0];
 880             }
 881         }
 882         else
 883         {
 884             return NULL;
 885         }
 886     }
 887 }
 888
 889 void * pcmbuf_request_voice_buffer(int *count)
 890 {
 891     /* A get-it-to-work-for-now hack (audio status could change by
 892        completion) */
 893     if (audio_status() & AUDIO_STATUS_PLAY)
 894     {
 895         if (pcmbuf_read == NULL)
 896         {
 897             return NULL;
 898         }
 899         else if (pcmbuf_usage() >= 10 && pcmbuf_mix_free() >= 30 &&
 900                  (pcmbuf_mix_chunk || pcmbuf_read->link))
 901         {
 902             *count = MIN(*count, PCMBUF_MIX_CHUNK/4);
 903             return voicebuf;
 904         }
 905         else
 906         {
 907             return NULL;
 908         }
 909     }
 910     else
 911     {
 912         return pcmbuf_request_buffer(count);
 913     }
 914 }
 915
 916 bool pcmbuf_is_crossfade_active(void)
 917 {
 918     return crossfade_active || crossfade_init;
 919 }
 920
 921 void pcmbuf_write_complete(int count)
 922 {
 923     size_t length = (size_t)(unsigned int)count << 2;
 924
 925     if (crossfade_active)
 926     {
 927         flush_crossfade(fadebuf, length);
 928         if (!(crossfade_fade_in_rem || crossfade_chunk))
 929             crossfade_active = false;
 930     }
 931     else
 932     {
 933         audiobuffer_fillpos += length;
 934
 935         if (NEED_FLUSH(audiobuffer_pos + audiobuffer_fillpos))
 936             pcmbuf_flush_fillpos();
 937     }
 938 }
 939
 940 #if 0
 941 bool pcmbuf_insert_buffer(char *buf, int count)
 942 {
 943     size_t length = (size_t)(unsigned int)count << 2;
 944
 945     if (crossfade_active)
 946     {
 947         flush_crossfade(buf, length);
 948         if (!(crossfade_fade_in_rem || crossfade_chunk))
 949             crossfade_active = false;
 950     }
 951     else
 952     {
 953         if (!prepare_insert(length))
 954             return false;
 955         pcmbuf_flush_buffer(buf, length);
 956     }
 957     return true;
 958 }
 959 #endif
 960
 961 /* Generates a constant square wave sound with a given frequency
 962    in Hertz for a duration in milliseconds. */
 963 void pcmbuf_beep(unsigned int frequency, size_t duration, int amplitude)
 964 {
 965     unsigned int count = 0, i = 0;
 966     unsigned int interval = NATIVE_FREQUENCY / frequency;
 967     int32_t sample;
 968     int16_t *buf;
 969     int16_t *pcmbuf_end = (int16_t *)fadebuf;
 970     size_t samples = NATIVE_FREQUENCY / 1000 * duration;
 971
 972     if (pcm_is_playing() && pcmbuf_read != NULL)
 973     {
 974         if (pcmbuf_read->link)
 975         {
 976             /* Get the next chunk */
 977             char *pcmbuf_mix_buf = pcmbuf_read->link->addr;
 978             /* Give at least 1/8s clearance. */
 979             buf = (int16_t *)&pcmbuf_mix_buf[NATIVE_FREQUENCY * 4 / 8];
 980         }
 981         else
 982         {
 983             logf("No place to beep");
 984             return;
 985         }
 986
 987         while (i++ < samples)
 988         {
 989             sample = *buf;
 990             *buf++ = clip_sample_16(sample + amplitude);
 991             if (buf > pcmbuf_end)
 992                 buf = (int16_t *)audiobuffer;
 993             sample = *buf;
 994             *buf++ = clip_sample_16(sample + amplitude);
 995
 996             /* Toggle square wav side */
 997             if (++count >= interval)
 998             {
 999                 count = 0;
1000                 amplitude = -amplitude;
1001             }
1002             if (buf > pcmbuf_end)
1003                 buf = (int16_t *)audiobuffer;
1004         }
1005     }
1006     else
1007     {
1008         buf = (int16_t *)audiobuffer;
1009         while (i++ < samples)
1010         {
1011             *buf++ = amplitude;
1012             if (buf > pcmbuf_end)
1013                 buf = (int16_t *)audiobuffer;
1014             *buf++ = amplitude;
1015
1016             /* Toggle square wav side */
1017             if (++count >= interval)
1018             {
1019                 count = 0;
1020                 amplitude = -amplitude;
1021             }
1022             if (buf > pcmbuf_end)
1023                 buf = (int16_t *)audiobuffer;
1024         }
1025         pcm_play_data(NULL, (unsigned char *)audiobuffer, samples * 4);
1026     }
1027 }
1028
1029 /* Returns pcm buffer usage in percents (0 to 100). */
1030 int pcmbuf_usage(void)
1031 {
1032     return pcmbuf_unplayed_bytes * 100 / pcmbuf_size;
1033 }
1034
1035 int pcmbuf_mix_free(void)
1036 {
1037     if (pcmbuf_mix_chunk)
1038     {
1039         size_t my_mix_end =
1040             (size_t)&((int16_t *)pcmbuf_mix_chunk->addr)[pcmbuf_mix_sample];
1041         size_t my_write_pos = (size_t)&audiobuffer[audiobuffer_pos];
1042         if (my_write_pos < my_mix_end)
1043             my_write_pos += pcmbuf_size;
1044         return (my_write_pos - my_mix_end) * 100 / pcmbuf_unplayed_bytes;
1045     }
1046     return 100;
1047 }
1048
1049 void pcmbuf_write_voice_complete(int count)
1050 {
1051     /* A get-it-to-work-for-now hack (audio status could have changed) */
1052     if (!(audio_status() & AUDIO_STATUS_PLAY))
1053     {
1054         pcmbuf_write_complete(count);
1055         return;
1056     }
1057
1058     int16_t *ibuf = (int16_t *)voicebuf;
1059     int16_t *obuf;
1060     size_t chunk_samples;
1061
1062     if (pcmbuf_mix_chunk == NULL && pcmbuf_read != NULL)
1063     {
1064         pcmbuf_mix_chunk = pcmbuf_read->link;
1065         /* Start 1/8s into the next chunk */
1066         pcmbuf_mix_sample = NATIVE_FREQUENCY * 4 / 16;
1067     }
1068
1069     if (!pcmbuf_mix_chunk)
1070         return;
1071
1072     obuf = (int16_t *)pcmbuf_mix_chunk->addr;
1073     chunk_samples = pcmbuf_mix_chunk->size / sizeof (int16_t);
1074
1075     count <<= 1;
1076
1077     while (count-- > 0)
1078     {
1079         int32_t sample = *ibuf++;
1080
1081         if (pcmbuf_mix_sample >= chunk_samples)
1082         {
1083             pcmbuf_mix_chunk = pcmbuf_mix_chunk->link;
1084             if (!pcmbuf_mix_chunk)
1085                 return;
1086             pcmbuf_mix_sample = 0;
1087             obuf = pcmbuf_mix_chunk->addr;
1088             chunk_samples = pcmbuf_mix_chunk->size / 2;
1089         }
1090         sample += obuf[pcmbuf_mix_sample] >> 2;
1091         obuf[pcmbuf_mix_sample++] = clip_sample_16(sample);
1092     }
1093 }
1094
1095 void pcmbuf_crossfade_enable(bool on_off)
1096 {
1097 #if MEM > 1
1098     /* Next setting to be used, not applied now */
1099     crossfade_enabled_pending = on_off;
1100 #endif
1101     (void)on_off;
1102 }
1103
1104 void pcmbuf_crossfade_enable_finished(void)
1105 {
1106     /* Copy the pending setting over now */
1107     crossfade_enabled = crossfade_enabled_pending;
1108     pcmbuf_set_watermark_bytes();
1109 }
1110
1111 bool pcmbuf_is_crossfade_enabled(void)
1112 {
1113     if (global_settings.crossfade == CROSSFADE_ENABLE_SHUFFLE)
1114         return global_settings.playlist_shuffle;
1115
1116     return crossfade_enabled;
1117 }