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  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21 #include <stdio.h>
  22 #include "config.h"
  23 #include "system.h"
  24 #include "debug.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 <string.h>
  33 #include "buffer.h"
  34 #include "settings.h"
  35 #include "audio.h"
  36 #include "voice_thread.h"
  37 #include "dsp.h"
  38 #include "thread.h"
  39
  40 /* Clip sample to signed 16 bit range */
  41 static inline int32_t clip_sample_16(int32_t sample)
  42 {
  43     if ((int16_t)sample != sample)
  44         sample = 0x7fff ^ (sample >> 31);
  45     return sample;
  46 }
  47
  48 #if MEMORYSIZE > 2
  49 /* Keep watermark high for iPods at least (2s) */
  50 #define PCMBUF_WATERMARK     (NATIVE_FREQUENCY * 4 * 2)
  51 #else
  52 #define PCMBUF_WATERMARK     (NATIVE_FREQUENCY * 1) /* 0.25 seconds */
  53 #endif
  54
  55 /* Structure we can use to queue pcm chunks in memory to be played
  56  * by the driver code. */
  57 struct pcmbufdesc
  58 {
  59     void *addr;
  60     size_t size;
  61     struct pcmbufdesc* link;
  62     /* Call this when the buffer has been played */
  63     void (*callback)(void);
  64 };
  65
  66 #define PCMBUF_DESCS(bufsize) \
  67     ((bufsize) / PCMBUF_MINAVG_CHUNK)
  68 #define PCMBUF_DESCS_SIZE(bufsize) \
  69     (PCMBUF_DESCS(bufsize)*sizeof(struct pcmbufdesc))
  70
  71 /* Size of the PCM buffer. */
  72 static size_t pcmbuf_size IDATA_ATTR = 0;
  73 static char *pcmbuf_bufend IDATA_ATTR;
  74 static char *audiobuffer IDATA_ATTR;
  75 /* Current audio buffer write index. */
  76 static size_t audiobuffer_pos IDATA_ATTR;
  77 /* Amount audiobuffer_pos will be increased.*/
  78 static size_t audiobuffer_fillpos IDATA_ATTR;
  79 static char *fadebuf IDATA_ATTR;
  80 static char *voicebuf IDATA_ATTR;
  81
  82 static void (*pcmbuf_event_handler)(void) IDATA_ATTR;
  83 static void (*position_callback)(size_t size) IDATA_ATTR;
  84
  85 /* Crossfade related state */
  86 static bool crossfade_enabled;
  87 static bool crossfade_enabled_pending;
  88 static bool crossfade_mixmode;
  89 static bool crossfade_active IDATA_ATTR;
  90 static bool crossfade_init IDATA_ATTR;
  91
  92 /* Track the current location for processing crossfade */
  93 static struct pcmbufdesc *crossfade_chunk IDATA_ATTR;
  94 #ifdef HAVE_CROSSFADE
  95 static size_t crossfade_sample IDATA_ATTR;
  96
  97 /* Counters for fading in new data */
  98 static size_t crossfade_fade_in_total IDATA_ATTR;
  99 static size_t crossfade_fade_in_rem IDATA_ATTR;
 100 #endif
 101
 102 static struct pcmbufdesc *pcmbuf_read IDATA_ATTR;
 103 static struct pcmbufdesc *pcmbuf_read_end IDATA_ATTR;
 104 static struct pcmbufdesc *pcmbuf_write IDATA_ATTR;
 105 static struct pcmbufdesc *pcmbuf_write_end IDATA_ATTR;
 106 static size_t last_chunksize IDATA_ATTR;
 107
 108 static size_t pcmbuf_unplayed_bytes IDATA_ATTR;
 109 static size_t pcmbuf_watermark IDATA_ATTR;
 110
 111 static struct pcmbufdesc *pcmbuf_mix_chunk IDATA_ATTR;
 112 static size_t pcmbuf_mix_sample IDATA_ATTR;
 113
 114 static bool low_latency_mode = false;
 115 static bool pcmbuf_flush;
 116
 117 #ifdef HAVE_PRIORITY_SCHEDULING
 118 static int codec_thread_priority = PRIORITY_PLAYBACK;
 119 #endif
 120
 121 extern unsigned int codec_thread_id;
 122
 123 /* Helpful macros for use in conditionals this assumes some of the above
 124  * static variable names */
 125 #define NEED_FLUSH(position) \
 126     (audiobuffer_fillpos > PCMBUF_TARGET_CHUNK || position >= pcmbuf_size)
 127 #define LOW_DATA(quarter_secs) \
 128     (pcmbuf_unplayed_bytes < NATIVE_FREQUENCY * quarter_secs)
 129
 130 static bool prepare_insert(size_t length);
 131 static void pcmbuf_under_watermark(bool under);
 132 static bool pcmbuf_flush_fillpos(void);
 133
 134 #define CALL_IF_EXISTS(function, args...) if (function) function(args)
 135 /* This function has 2 major logical parts (separated by brackets both for
 136  * readability and variable scoping).  The first part performs the
 137  * operastions related to finishing off the last buffer we fed to the DMA.
 138  * The second part performs the operations involved in sending a new buffer
 139  * to the DMA.  Finally the function checks the status of the buffer and
 140  * boosts if necessary */
 141 static void pcmbuf_callback(unsigned char** start, size_t* size) ICODE_ATTR;
 142 static void pcmbuf_callback(unsigned char** start, size_t* size)
 143 {
 144     {
 145         struct pcmbufdesc *pcmbuf_current = pcmbuf_read;
 146         /* Take the finished buffer out of circulation */
 147         pcmbuf_read = pcmbuf_current->link;
 148
 149         /* The buffer is finished, call the callback functions */
 150         CALL_IF_EXISTS(position_callback, last_chunksize);
 151         CALL_IF_EXISTS(pcmbuf_current->callback);
 152
 153         /* Put the finished buffer back into circulation */
 154         pcmbuf_write_end->link = pcmbuf_current;
 155         pcmbuf_write_end = pcmbuf_current;
 156
 157         /* If we've read over the mix chunk while it's still mixing there */
 158         if (pcmbuf_current == pcmbuf_mix_chunk)
 159             pcmbuf_mix_chunk = NULL;
 160         /* If we've read over the crossfade chunk while it's still fading */
 161         if (pcmbuf_current == crossfade_chunk)
 162             crossfade_chunk = pcmbuf_read;
 163     }
 164
 165     {
 166         /* Send the new buffer to the pcm */
 167         struct pcmbufdesc *pcmbuf_new = pcmbuf_read;
 168         size_t *realsize = size;
 169         unsigned char** realstart = start;
 170         if(pcmbuf_new)
 171         {
 172             size_t current_size = pcmbuf_new->size;
 173
 174             pcmbuf_unplayed_bytes -= current_size;
 175             last_chunksize = current_size;
 176             *realsize = current_size;
 177             *realstart = pcmbuf_new->addr;
 178         }
 179         else
 180         {
 181             /* No more buffers */
 182             last_chunksize = 0;
 183             *realsize = 0;
 184             *realstart = NULL;
 185             CALL_IF_EXISTS(pcmbuf_event_handler);
 186         }
 187     }
 188 }
 189
 190 void pcmbuf_set_position_callback(void (*callback)(size_t size))
 191 {
 192     position_callback = callback;
 193 }
 194
 195 static void pcmbuf_set_watermark_bytes(void)
 196 {
 197     pcmbuf_watermark = (crossfade_enabled && pcmbuf_size) ?
 198         /* If crossfading, try to keep the buffer full other than 1 second */
 199         (pcmbuf_size - (NATIVE_FREQUENCY * 4 * 1)) :
 200         /* Otherwise, just use the default */
 201         PCMBUF_WATERMARK;
 202 }
 203
 204 /* This is really just part of pcmbuf_flush_fillpos, but is easier to keep
 205  * in a separate function for the moment */
 206 static inline void pcmbuf_add_chunk(void)
 207 {
 208     register size_t size = audiobuffer_fillpos;
 209     /* Grab the next description to write, and change the write pointer */
 210     register struct pcmbufdesc *pcmbuf_current = pcmbuf_write;
 211     pcmbuf_write = pcmbuf_current->link;
 212     /* Fill in the values in the new buffer chunk */
 213     pcmbuf_current->addr = &audiobuffer[audiobuffer_pos];
 214     pcmbuf_current->size = size;
 215     pcmbuf_current->callback = pcmbuf_event_handler;
 216     pcmbuf_current->link = NULL;
 217     /* This is single use only */
 218     pcmbuf_event_handler = NULL;
 219     if (pcmbuf_read != NULL) {
 220         if (pcmbuf_flush)
 221         {
 222             pcmbuf_write_end->link = pcmbuf_read->link;
 223             pcmbuf_read->link = pcmbuf_current;
 224             while (pcmbuf_write_end->link)
 225             {
 226                 pcmbuf_write_end = pcmbuf_write_end->link;
 227                 pcmbuf_unplayed_bytes -= pcmbuf_write_end->size;
 228             }
 229             pcmbuf_flush = false;
 230         }
 231         /* If there is already a read buffer setup, add to it */
 232         else
 233             pcmbuf_read_end->link = pcmbuf_current;
 234     } else {
 235         /* Otherwise create the buffer */
 236         pcmbuf_read = pcmbuf_current;
 237     }
 238     /* This is now the last buffer to read */
 239     pcmbuf_read_end = pcmbuf_current;
 240
 241     /* Update bytes counters */
 242     pcmbuf_unplayed_bytes += size;
 243
 244     audiobuffer_pos += size;
 245     if (audiobuffer_pos >= pcmbuf_size)
 246         audiobuffer_pos -= pcmbuf_size;
 247
 248     audiobuffer_fillpos = 0;
 249 }
 250
 251 #ifdef HAVE_PRIORITY_SCHEDULING
 252 static void boost_codec_thread(bool boost)
 253 {
 254     /* Keep voice and codec threads at the same priority or else voice
 255      * will starve if the codec thread's priority is boosted. */
 256     if (boost)
 257     {
 258         int priority = (PRIORITY_PLAYBACK - PRIORITY_PLAYBACK_MAX)*pcmbuf_unplayed_bytes
 259                           / (2*NATIVE_FREQUENCY) + PRIORITY_PLAYBACK_MAX;
 260
 261         if (priority != codec_thread_priority)
 262         {
 263             codec_thread_priority = priority;
 264             thread_set_priority(codec_thread_id, priority);
 265             voice_thread_set_priority(priority);
 266         }
 267     }
 268     else if (codec_thread_priority != PRIORITY_PLAYBACK)
 269     {
 270         thread_set_priority(codec_thread_id, PRIORITY_PLAYBACK);
 271         voice_thread_set_priority(PRIORITY_PLAYBACK);
 272         codec_thread_priority = PRIORITY_PLAYBACK;
 273     }
 274 }
 275 #endif /* HAVE_PRIORITY_SCHEDULING */
 276
 277 static void pcmbuf_under_watermark(bool under)
 278 {
 279     /* Only codec thread initiates boost - voice boosts the cpu when playing
 280        a clip */
 281 #ifndef SIMULATOR
 282     if (thread_get_current() == codec_thread_id)
 283 #endif /* SIMULATOR */
 284     {
 285         if (under)
 286         {
 287             /* Fill audio buffer by boosting cpu */
 288             trigger_cpu_boost();
 289 #ifdef HAVE_PRIORITY_SCHEDULING
 290             /* If buffer is critically low, override UI priority, else
 291                set back to the original priority. */
 292             boost_codec_thread(LOW_DATA(2) && pcm_is_playing());
 293 #endif
 294         }
 295         else
 296         {
 297 #ifdef HAVE_PRIORITY_SCHEDULING
 298             boost_codec_thread(false);
 299 #endif
 300         }
 301     }
 302
 303     /* Disable crossfade if < .5s of audio */
 304     if (LOW_DATA(2))
 305     {
 306         crossfade_active = false;
 307     }
 308 }
 309
 310 void pcmbuf_set_event_handler(void (*event_handler)(void))
 311 {
 312     pcmbuf_event_handler = event_handler;
 313 }
 314
 315 unsigned int pcmbuf_get_latency(void)
 316 {
 317     /* Be careful how this calculation is rearranged, it's easy to overflow */
 318     size_t bytes = pcmbuf_unplayed_bytes + pcm_get_bytes_waiting();
 319     return bytes / 4 / (NATIVE_FREQUENCY/1000);
 320 }
 321
 322 void pcmbuf_set_low_latency(bool state)
 323 {
 324     low_latency_mode = state;
 325 }
 326
 327 bool pcmbuf_is_lowdata(void)
 328 {
 329     if (!pcm_is_playing() || pcm_is_paused() ||
 330             crossfade_init || crossfade_active)
 331         return false;
 332
 333 #if MEMORYSIZE > 2
 334     /* 1 seconds of buffer is low data */
 335     return LOW_DATA(4);
 336 #else
 337     /* under watermark is low data */
 338     return (pcmbuf_unplayed_bytes < pcmbuf_watermark);
 339 #endif
 340 }
 341
 342 /* Amount of bytes left in the buffer. */
 343 inline size_t pcmbuf_free(void)
 344 {
 345     if (pcmbuf_read != NULL)
 346     {
 347         void *read = pcmbuf_read->addr;
 348         void *write = &audiobuffer[audiobuffer_pos + audiobuffer_fillpos];
 349         if (read < write)
 350             return (size_t)(read - write) + pcmbuf_size;
 351         else
 352             return (size_t) (read - write);
 353     }
 354     return pcmbuf_size;
 355 }
 356
 357 bool pcmbuf_crossfade_init(bool manual_skip)
 358 {
 359     /* Can't do two crossfades at once and, no fade if pcm is off now */
 360     if (crossfade_init || crossfade_active || !pcm_is_playing())
 361     {
 362         pcmbuf_play_stop();
 363         return false;
 364     }
 365
 366     trigger_cpu_boost();
 367
 368     /* Not enough data, or crossfade disabled, flush the old data instead */
 369     if (LOW_DATA(2) || !pcmbuf_is_crossfade_enabled() || low_latency_mode)
 370     {
 371         pcmbuf_flush_fillpos();
 372         pcmbuf_flush = true;
 373         return false;
 374     }
 375
 376     /* Don't enable mix mode when skipping tracks manually. */
 377     if (manual_skip)
 378         crossfade_mixmode = false;
 379     else
 380         crossfade_mixmode = global_settings.crossfade_fade_out_mixmode;
 381
 382     crossfade_init = true;
 383
 384     return true;
 385
 386 }
 387
 388 void pcmbuf_play_stop(void)
 389 {
 390     pcm_play_stop();
 391
 392     pcmbuf_unplayed_bytes = 0;
 393     pcmbuf_mix_chunk = NULL;
 394     if (pcmbuf_read) {
 395         pcmbuf_write_end->link = pcmbuf_read;
 396         pcmbuf_write_end = pcmbuf_read_end;
 397         pcmbuf_read = pcmbuf_read_end = NULL;
 398     }
 399     audiobuffer_pos = 0;
 400     audiobuffer_fillpos = 0;
 401     crossfade_init = false;
 402     crossfade_active = false;
 403     pcmbuf_flush = false;
 404
 405 #ifdef HAVE_PRIORITY_SCHEDULING
 406     /* Can unboost the codec thread here no matter who's calling */
 407     boost_codec_thread(false);
 408 #endif
 409 }
 410
 411 int pcmbuf_used_descs(void)
 412 {
 413     struct pcmbufdesc *pcmbuf_temp = pcmbuf_read;
 414     unsigned int i = 0;
 415     while (pcmbuf_temp) {
 416         pcmbuf_temp = pcmbuf_temp->link;
 417         i++;
 418     }
 419     return i;
 420 }
 421
 422 int pcmbuf_descs(void)
 423 {
 424     return PCMBUF_DESCS(pcmbuf_size);
 425 }
 426
 427 static void pcmbuf_init_pcmbuffers(void)
 428 {
 429     struct pcmbufdesc *next = pcmbuf_write;
 430     next++;
 431     pcmbuf_write_end = pcmbuf_write;
 432     while ((void *)next < (void *)pcmbuf_bufend) {
 433         pcmbuf_write_end->link=next;
 434         pcmbuf_write_end=next;
 435         next++;
 436     }
 437 }
 438
 439 static size_t pcmbuf_get_next_required_pcmbuf_size(void)
 440 {
 441     size_t seconds = 1;
 442
 443     if (crossfade_enabled_pending)
 444         seconds += global_settings.crossfade_fade_out_delay
 445                    + global_settings.crossfade_fade_out_duration;
 446
 447 #if MEMORYSIZE > 2
 448     /* Buffer has to be at least 2s long. */
 449     seconds += 2;
 450 #endif
 451     logf("pcmbuf len: %ld", (long)seconds);
 452     return seconds * (NATIVE_FREQUENCY*4); /* 2 channels + 2 bytes/sample */
 453 }
 454
 455 static char *pcmbuf_calc_audiobuffer_ptr(size_t bufsize)
 456 {
 457     return pcmbuf_bufend - (bufsize + PCMBUF_MIX_CHUNK * 2 +
 458                PCMBUF_DESCS_SIZE(bufsize));
 459 }
 460
 461 bool pcmbuf_is_same_size(void)
 462 {
 463     if (audiobuffer == NULL)
 464         return true; /* Not set up yet even once so always */
 465
 466     size_t bufsize = pcmbuf_get_next_required_pcmbuf_size();
 467     return pcmbuf_calc_audiobuffer_ptr(bufsize) == audiobuffer;
 468 }
 469
 470 /* Initialize the pcmbuffer the structure looks like this:
 471  * ...|---------PCMBUF---------|FADEBUF|VOICEBUF|DESCS|... */
 472 size_t pcmbuf_init(unsigned char *bufend)
 473 {
 474     pcmbuf_bufend = bufend;
 475     pcmbuf_size = pcmbuf_get_next_required_pcmbuf_size();
 476     audiobuffer = pcmbuf_calc_audiobuffer_ptr(pcmbuf_size);
 477     fadebuf = &audiobuffer[pcmbuf_size];
 478     voicebuf = &fadebuf[PCMBUF_MIX_CHUNK];
 479     pcmbuf_write = (struct pcmbufdesc *)&voicebuf[PCMBUF_MIX_CHUNK];
 480
 481     pcmbuf_init_pcmbuffers();
 482
 483     position_callback = NULL;
 484     pcmbuf_event_handler = NULL;
 485
 486     pcmbuf_crossfade_enable_finished();
 487
 488     pcmbuf_play_stop();
 489
 490     return pcmbuf_bufend - audiobuffer;
 491 }
 492
 493 size_t pcmbuf_get_bufsize(void)
 494 {
 495     return pcmbuf_size;
 496 }
 497
 498 #ifdef ROCKBOX_HAS_LOGF
 499 unsigned char * pcmbuf_get_meminfo(size_t *length)
 500 {
 501     *length = pcmbuf_bufend - audiobuffer;
 502     return audiobuffer;
 503 }
 504 #endif
 505
 506 void pcmbuf_pause(bool pause)
 507 {
 508     if (pcm_is_playing())
 509         pcm_play_pause(!pause);
 510     else if (!pause)
 511         pcmbuf_play_start();
 512 }
 513
 514 /* Force playback. */
 515 void pcmbuf_play_start(void)
 516 {
 517     if (!pcm_is_playing() && pcmbuf_unplayed_bytes && pcmbuf_read != NULL)
 518     {
 519         last_chunksize = pcmbuf_read->size;
 520         pcmbuf_unplayed_bytes -= last_chunksize;
 521         pcm_play_data(pcmbuf_callback,
 522             (unsigned char *)pcmbuf_read->addr, last_chunksize);
 523     }
 524 }
 525
 526 /**
 527  * Commit samples waiting to the pcm buffer.
 528  */
 529 static bool pcmbuf_flush_fillpos(void)
 530 {
 531     if (audiobuffer_fillpos) {
 532         /* Never use the last buffer descriptor */
 533         while (pcmbuf_write == pcmbuf_write_end) {
 534             /* If this happens, something is being stupid */
 535             if (!pcm_is_playing()) {
 536                 logf("pcmbuf_flush_fillpos error");
 537                 pcmbuf_play_start();
 538             }
 539             /* Let approximately one chunk of data playback */
 540             sleep(HZ*PCMBUF_TARGET_CHUNK/(NATIVE_FREQUENCY*4));
 541         }
 542         pcmbuf_add_chunk();
 543         return true;
 544     }
 545     return false;
 546 }
 547
 548 /**
 549  * Low memory targets don't have crossfade, so don't compile crossfade
 550  * specific code in order to save some memory.                         */
 551
 552 #ifdef HAVE_CROSSFADE
 553 /**
 554  * Completely process the crossfade fade out effect with current pcm buffer.
 555  */
 556 static void crossfade_process_buffer(size_t fade_in_delay,
 557         size_t fade_out_delay, size_t fade_out_rem)
 558 {
 559     if (!crossfade_mixmode)
 560     {
 561         /* Fade out the specified amount of the already processed audio */
 562         size_t total_fade_out = fade_out_rem;
 563         size_t fade_out_sample;
 564         struct pcmbufdesc *fade_out_chunk = crossfade_chunk;
 565
 566         /* Find the right chunk to start fading out */
 567         fade_out_delay += crossfade_sample * 2;
 568         while (fade_out_delay != 0 && fade_out_delay >= fade_out_chunk->size)
 569         {
 570             fade_out_delay -= fade_out_chunk->size;
 571             fade_out_chunk = fade_out_chunk->link;
 572         }
 573         /* The start sample within the chunk */
 574         fade_out_sample = fade_out_delay / 2;
 575
 576         while (fade_out_rem > 0)
 577         {
 578             /* Each 1/10 second of audio will have the same fade applied */
 579             size_t block_rem = MIN(NATIVE_FREQUENCY * 4 / 10, fade_out_rem);
 580             int factor = (fade_out_rem << 8) / total_fade_out;
 581
 582             fade_out_rem -= block_rem;
 583
 584             /* Fade this block */
 585             while (block_rem > 0 && fade_out_chunk != NULL)
 586             {
 587                 /* Fade one sample */
 588                 int16_t *buf = (int16_t *)fade_out_chunk->addr;
 589                 int32_t sample = buf[fade_out_sample];
 590                 buf[fade_out_sample++] = (sample * factor) >> 8;
 591
 592                 block_rem -= 2;
 593                 /* Move to the next chunk as needed */
 594                 if (fade_out_sample * 2 >= fade_out_chunk->size)
 595                 {
 596                     fade_out_chunk = fade_out_chunk->link;
 597                     fade_out_sample = 0;
 598                 }
 599             }
 600         }
 601     }
 602
 603     /* Find the right chunk and sample to start fading in */
 604     fade_in_delay += crossfade_sample * 2;
 605     while (fade_in_delay != 0 && fade_in_delay >= crossfade_chunk->size)
 606     {
 607         fade_in_delay -= crossfade_chunk->size;
 608         crossfade_chunk = crossfade_chunk->link;
 609     }
 610     crossfade_sample = fade_in_delay / 2;
 611     logf("process done!");
 612 }
 613
 614 /* Initializes crossfader, calculates all necessary parameters and
 615  * performs fade-out with the pcm buffer.  */
 616 static void crossfade_start(void)
 617 {
 618     size_t crossfade_rem;
 619     size_t crossfade_need;
 620     size_t fade_out_rem;
 621     size_t fade_out_delay;
 622     size_t fade_in_delay;
 623
 624     crossfade_init = false;
 625     /* Reject crossfade if less than .5s of data */
 626     if (LOW_DATA(2)) {
 627         logf("crossfade rejected");
 628         pcmbuf_play_stop();
 629         return ;
 630     }
 631
 632     logf("crossfade_start");
 633     pcmbuf_flush_fillpos();
 634     crossfade_active = true;
 635
 636     /* Initialize the crossfade buffer size to all of the buffered data that
 637      * has not yet been sent to the DMA */
 638     crossfade_rem = pcmbuf_unplayed_bytes;
 639     crossfade_chunk = pcmbuf_read->link;
 640     crossfade_sample = 0;
 641
 642     /* Get fade out delay from settings. */
 643     fade_out_delay =
 644         NATIVE_FREQUENCY * global_settings.crossfade_fade_out_delay * 4;
 645
 646     /* Get fade out duration from settings. */
 647     fade_out_rem =
 648         NATIVE_FREQUENCY * global_settings.crossfade_fade_out_duration * 4;
 649
 650     crossfade_need = fade_out_delay + fade_out_rem;
 651     /* We want only to modify the last part of the buffer. */
 652     if (crossfade_rem > crossfade_need)
 653     {
 654         size_t crossfade_extra = crossfade_rem - crossfade_need;
 655         while (crossfade_extra > crossfade_chunk->size)
 656         {
 657             crossfade_extra -= crossfade_chunk->size;
 658             crossfade_chunk = crossfade_chunk->link;
 659         }
 660         crossfade_sample = crossfade_extra / 2;
 661     }
 662     /* Truncate fade out duration if necessary. */
 663     else if (crossfade_rem < crossfade_need)
 664     {
 665         size_t crossfade_short = crossfade_need - crossfade_rem;
 666         if (fade_out_rem >= crossfade_short)
 667             fade_out_rem -= crossfade_short;
 668         else
 669         {
 670             fade_out_delay -= crossfade_short - fade_out_rem;
 671             fade_out_rem = 0;
 672         }
 673     }
 674
 675     /* Get also fade in duration and delays from settings. */
 676     crossfade_fade_in_total =
 677         NATIVE_FREQUENCY * global_settings.crossfade_fade_in_duration * 4;
 678     crossfade_fade_in_rem = crossfade_fade_in_total;
 679
 680     fade_in_delay =
 681         NATIVE_FREQUENCY * global_settings.crossfade_fade_in_delay * 4;
 682
 683     crossfade_process_buffer(fade_in_delay, fade_out_delay, fade_out_rem);
 684 }
 685
 686 /* Returns the number of bytes _NOT_ mixed */
 687 static size_t crossfade_fade_mix(int factor, const char *buf, size_t fade_rem)
 688 {
 689     const int16_t *input_buf = (const int16_t *)buf;
 690     int16_t *output_buf = (int16_t *)(crossfade_chunk->addr);
 691     int16_t *chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 692     output_buf = &output_buf[crossfade_sample];
 693     int32_t sample;
 694
 695     while (fade_rem)
 696     {
 697         /* fade left and right channel at once to keep buffer alignment */
 698         sample = *input_buf++;
 699         sample = ((sample * factor) >> 8) + *output_buf;
 700         *output_buf++ = clip_sample_16(sample);
 701
 702         sample = *input_buf++;
 703         sample = ((sample * factor) >> 8) + *output_buf;
 704         *output_buf++ = clip_sample_16(sample);
 705
 706         fade_rem -= 4; /* 2 samples, each 16 bit -> 4 bytes */
 707
 708         if (output_buf >= chunk_end)
 709         {
 710             crossfade_chunk = crossfade_chunk->link;
 711             if (!crossfade_chunk)
 712                 return fade_rem;
 713             output_buf = (int16_t *)crossfade_chunk->addr;
 714             chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 715         }
 716     }
 717     crossfade_sample = output_buf - (int16_t *)crossfade_chunk->addr;
 718     return 0;
 719 }
 720
 721 /* Returns the number of bytes _NOT_ mixed */
 722 static size_t crossfade_mix(const char *buf, size_t length)
 723 {
 724     const int16_t *input_buf = (const int16_t *)buf;
 725     int16_t *output_buf = (int16_t *)crossfade_chunk->addr;
 726     int16_t *chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 727     output_buf = &output_buf[crossfade_sample];
 728     int32_t sample;
 729
 730     while (length)
 731     {
 732         /* fade left and right channel at once to keep buffer alignment */
 733         sample = *input_buf++ + *output_buf;
 734         *output_buf++ = clip_sample_16(sample);
 735
 736         sample = *input_buf++ + *output_buf;
 737         *output_buf++ = clip_sample_16(sample);
 738
 739         length -= 4; /* 2 samples, each 16 bit -> 4 bytes */
 740
 741         if (output_buf >= chunk_end)
 742         {
 743             crossfade_chunk = crossfade_chunk->link;
 744             if (!crossfade_chunk)
 745                 return length;
 746
 747             output_buf = (int16_t *)crossfade_chunk->addr;
 748             chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 749         }
 750     }
 751     crossfade_sample = output_buf - (int16_t *)crossfade_chunk->addr;
 752     return 0;
 753 }
 754
 755 static void pcmbuf_flush_buffer(const char *buf, size_t length)
 756 {
 757     size_t copy_n;
 758     while (length > 0) {
 759         size_t audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 760         if (NEED_FLUSH(audiobuffer_index))
 761         {
 762             pcmbuf_flush_fillpos();
 763             audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 764         }
 765         copy_n = MIN(length, pcmbuf_size - audiobuffer_index);
 766         memcpy(&audiobuffer[audiobuffer_index], buf, copy_n);
 767         buf += copy_n;
 768         audiobuffer_fillpos += copy_n;
 769         length -= copy_n;
 770     }
 771 }
 772
 773 static void flush_crossfade(char *buf, size_t length)
 774 {
 775     if (length)
 776     {
 777         if (crossfade_fade_in_rem)
 778         {
 779             size_t samples;
 780             int16_t *input_buf;
 781
 782             /* Fade factor for this packet */
 783             int factor =
 784                 ((crossfade_fade_in_total - crossfade_fade_in_rem) << 8) /
 785                 crossfade_fade_in_total;
 786             /* Bytes to fade */
 787             size_t fade_rem = MIN(length, crossfade_fade_in_rem);
 788
 789             /* We _will_ fade this many bytes */
 790             crossfade_fade_in_rem -= fade_rem;
 791
 792             if (crossfade_chunk)
 793             {
 794                 /* Mix the data */
 795                 size_t fade_total = fade_rem;
 796                 fade_rem = crossfade_fade_mix(factor, buf, fade_rem);
 797                 length -= fade_total - fade_rem;
 798                 buf += fade_total - fade_rem;
 799                 if (!length)
 800                     return;
 801                 if (!fade_rem)
 802                     goto fade_done;
 803             }
 804
 805             samples = fade_rem / 2;
 806             input_buf = (int16_t *)buf;
 807             /* Fade remaining samples in place */
 808             while (samples)
 809             {
 810                 int32_t sample = *input_buf;
 811                 *input_buf++ = (sample * factor) >> 8;
 812                 samples--;
 813             }
 814         }
 815
 816 fade_done:
 817         if (crossfade_chunk)
 818         {
 819             /* Mix the data */
 820             size_t mix_total = length;
 821             length = crossfade_mix(buf, length);
 822             buf += mix_total - length;
 823             if (!length)
 824                 return;
 825         }
 826
 827         /* Flush samples to the buffer */
 828         while (!prepare_insert(length))
 829             sleep(1);
 830         pcmbuf_flush_buffer(buf, length);
 831     }
 832
 833 }
 834 #endif
 835
 836 static bool prepare_insert(size_t length)
 837 {
 838     if (low_latency_mode)
 839     {
 840         /* 1/4s latency. */
 841         if (!LOW_DATA(1) && pcm_is_playing())
 842             return false;
 843     }
 844
 845     /* Need to save PCMBUF_MIN_CHUNK to prevent wrapping overwriting */
 846     if (pcmbuf_free() < length + PCMBUF_MIN_CHUNK)
 847         return false;
 848
 849     if (!pcm_is_playing())
 850     {
 851         trigger_cpu_boost();
 852
 853         /* Pre-buffer up to watermark */
 854 #if MEMORYSIZE > 2
 855         if (!LOW_DATA(4))
 856 #else
 857         if (pcmbuf_unplayed_bytes > pcmbuf_watermark)
 858 #endif
 859         {
 860             logf("pcm starting");
 861             if (!(audio_status() & AUDIO_STATUS_PAUSE))
 862                 pcmbuf_play_start();
 863         }
 864     }
 865     else
 866         pcmbuf_under_watermark(pcmbuf_unplayed_bytes <= pcmbuf_watermark);
 867
 868     return true;
 869 }
 870
 871 void* pcmbuf_request_buffer(int *count)
 872 {
 873 #ifdef HAVE_CROSSFADE
 874     if (crossfade_init)
 875         crossfade_start();
 876 #endif
 877
 878     if (crossfade_active) {
 879         *count = MIN(*count, PCMBUF_MIX_CHUNK/4);
 880         return fadebuf;
 881     }
 882     else
 883     {
 884         if(prepare_insert(*count << 2))
 885         {
 886             size_t audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 887             if (pcmbuf_size - audiobuffer_index >= PCMBUF_MIN_CHUNK)
 888             {
 889                 /* Usual case, there's space here */
 890                 return &audiobuffer[audiobuffer_index];
 891             }
 892             else
 893             {
 894                 /* Flush and wrap the buffer */
 895                 pcmbuf_flush_fillpos();
 896                 audiobuffer_pos = 0;
 897                 return &audiobuffer[0];
 898             }
 899         }
 900         else
 901         {
 902             return NULL;
 903         }
 904     }
 905 }
 906
 907 void * pcmbuf_request_voice_buffer(int *count)
 908 {
 909     /* A get-it-to-work-for-now hack (audio status could change by
 910        completion) */
 911     if (audio_status() & AUDIO_STATUS_PLAY)
 912     {
 913         if (pcmbuf_read == NULL)
 914         {
 915             return NULL;
 916         }
 917         else if (pcmbuf_usage() >= 10 && pcmbuf_mix_free() >= 30 &&
 918                  (pcmbuf_mix_chunk || pcmbuf_read->link))
 919         {
 920             *count = MIN(*count, PCMBUF_MIX_CHUNK/4);
 921             return voicebuf;
 922         }
 923         else
 924         {
 925             return NULL;
 926         }
 927     }
 928     else
 929     {
 930         return pcmbuf_request_buffer(count);
 931     }
 932 }
 933
 934 bool pcmbuf_is_crossfade_active(void)
 935 {
 936     return crossfade_active || crossfade_init;
 937 }
 938
 939 void pcmbuf_write_complete(int count)
 940 {
 941     size_t length = (size_t)(unsigned int)count << 2;
 942 #ifdef HAVE_CROSSFADE
 943     if (crossfade_active)
 944     {
 945         flush_crossfade(fadebuf, length);
 946         if (!(crossfade_fade_in_rem || crossfade_chunk))
 947             crossfade_active = false;
 948     }
 949     else
 950 #endif
 951     {
 952         audiobuffer_fillpos += length;
 953
 954         if (NEED_FLUSH(audiobuffer_pos + audiobuffer_fillpos))
 955             pcmbuf_flush_fillpos();
 956     }
 957 }
 958
 959 #if 0
 960 bool pcmbuf_insert_buffer(char *buf, int count)
 961 {
 962     size_t length = (size_t)(unsigned int)count << 2;
 963
 964     if (crossfade_active)
 965     {
 966         flush_crossfade(buf, length);
 967         if (!(crossfade_fade_in_rem || crossfade_chunk))
 968             crossfade_active = false;
 969     }
 970     else
 971     {
 972         if (!prepare_insert(length))
 973             return false;
 974         pcmbuf_flush_buffer(buf, length);
 975     }
 976     return true;
 977 }
 978 #endif
 979
 980 #ifndef HAVE_HARDWARE_BEEP
 981 #define MINIBUF_SAMPLES (NATIVE_FREQUENCY / 1000 * KEYCLICK_DURATION)
 982 #define MINIBUF_SIZE (MINIBUF_SAMPLES*4)
 983
 984 /* Generates a constant square wave sound with a given frequency
 985    in Hertz for a duration in milliseconds. */
 986 void pcmbuf_beep(unsigned int frequency, size_t duration, int amplitude)
 987 {
 988     unsigned int step = 0xffffffffu / NATIVE_FREQUENCY * frequency;
 989     int32_t phase = 0;
 990     int16_t *bufptr, *bufstart, *bufend;
 991     int32_t sample;
 992     int nsamples = NATIVE_FREQUENCY / 1000 * duration;
 993     bool mix = pcmbuf_read != NULL && pcmbuf_read->link != NULL;
 994     int i;
 995
 996     bufend = SKIPBYTES((int16_t *)audiobuffer, pcmbuf_size);
 997
 998     /* Find the insertion point and set bufstart to the start of it */
 999     if (mix)
1000     {
1001         /* Get the currently playing chunk at the current position. */
1002         bufstart = (int16_t *)pcm_play_dma_get_peak_buffer(&i);
1003
1004         /* If above isn't implemented or pcm is stopped, no beepeth. */
1005         if (!bufstart || !pcm_is_playing())
1006             return;
1007
1008         /* Give 5ms clearance. */
1009         bufstart += NATIVE_FREQUENCY * 4 / 200;
1010
1011 #ifdef HAVE_PCM_DMA_ADDRESS
1012         /* Returned peak addresses are DMA addresses */
1013         bufend = pcm_dma_addr(bufend);
1014 #endif
1015
1016         /* Wrapped above? */
1017         if (bufstart >= bufend)
1018             bufstart -= pcmbuf_size;
1019
1020         /* NOTE: On some targets using hardware DMA, cache range flushing may
1021          * be required or the writes may not be picked up by the controller.
1022          * An incremental flush should be done periodically during the mixdown. */
1023     }
1024     else if (nsamples <= MINIBUF_SAMPLES)
1025     {
1026         static int16_t minibuf[MINIBUF_SAMPLES*2] __attribute__((aligned(4)));
1027         /* Use mini buffer */
1028         bufstart = minibuf;
1029         bufend = SKIPBYTES(bufstart, MINIBUF_SIZE);
1030     }
1031     else if (audio_buffer_state() != AUDIOBUF_STATE_TRASHED)
1032     {
1033         /* Use audiobuffer */
1034         bufstart = (int16_t *)audiobuffer;
1035     }
1036     else
1037     {
1038         /* No place */
1039         return;
1040     }
1041
1042     bufptr = bufstart;
1043
1044     /* Mix square wave into buffer */
1045     for (i = 0; i < nsamples; ++i)
1046     {
1047         int32_t amp = (phase >> 31) ^ (int32_t)amplitude;
1048         sample = mix ? *bufptr : 0;
1049         *bufptr++ = clip_sample_16(sample + amp);
1050         if (bufptr >= bufend)
1051             bufptr = (int16_t *)audiobuffer;
1052         sample = mix ? *bufptr : 0;
1053         *bufptr++ = clip_sample_16(sample + amp);
1054         if (bufptr >= bufend)
1055             bufptr = (int16_t *)audiobuffer;
1056
1057         phase += step;
1058     }
1059
1060     pcm_play_lock();
1061 #ifdef HAVE_RECORDING
1062     pcm_rec_lock();
1063 #endif
1064
1065     /* Kick off playback if required and it won't interfere */
1066     if (!pcm_is_playing()
1067 #ifdef HAVE_RECORDING
1068         && !pcm_is_recording()
1069 #endif
1070         )
1071     {
1072         pcm_play_data(NULL, (unsigned char *)bufstart, nsamples * 4);
1073     }
1074
1075     pcm_play_unlock();
1076 #ifdef HAVE_RECORDING
1077     pcm_rec_unlock();
1078 #endif
1079 }
1080 #endif /* HAVE_HARDWARE_BEEP */
1081
1082 /* Returns pcm buffer usage in percents (0 to 100). */
1083 int pcmbuf_usage(void)
1084 {
1085     return pcmbuf_unplayed_bytes * 100 / pcmbuf_size;
1086 }
1087
1088 int pcmbuf_mix_free(void)
1089 {
1090     if (pcmbuf_mix_chunk)
1091     {
1092         size_t my_mix_end =
1093             (size_t)&((int16_t *)pcmbuf_mix_chunk->addr)[pcmbuf_mix_sample];
1094         size_t my_write_pos = (size_t)&audiobuffer[audiobuffer_pos];
1095         if (my_write_pos < my_mix_end)
1096             my_write_pos += pcmbuf_size;
1097         return (my_write_pos - my_mix_end) * 100 / pcmbuf_unplayed_bytes;
1098     }
1099     return 100;
1100 }
1101
1102 void pcmbuf_write_voice_complete(int count)
1103 {
1104     /* A get-it-to-work-for-now hack (audio status could have changed) */
1105     if (!(audio_status() & AUDIO_STATUS_PLAY))
1106     {
1107         pcmbuf_write_complete(count);
1108         return;
1109     }
1110
1111     int16_t *ibuf = (int16_t *)voicebuf;
1112     int16_t *obuf;
1113     size_t chunk_samples;
1114
1115     if (pcmbuf_mix_chunk == NULL && pcmbuf_read != NULL)
1116     {
1117         pcmbuf_mix_chunk = pcmbuf_read->link;
1118         /* Start 1/8s into the next chunk */
1119         pcmbuf_mix_sample = NATIVE_FREQUENCY * 4 / 16;
1120     }
1121
1122     if (!pcmbuf_mix_chunk)
1123         return;
1124
1125     obuf = (int16_t *)pcmbuf_mix_chunk->addr;
1126     chunk_samples = pcmbuf_mix_chunk->size / sizeof (int16_t);
1127
1128     count <<= 1;
1129
1130     while (count-- > 0)
1131     {
1132         int32_t sample = *ibuf++;
1133
1134         if (pcmbuf_mix_sample >= chunk_samples)
1135         {
1136             pcmbuf_mix_chunk = pcmbuf_mix_chunk->link;
1137             if (!pcmbuf_mix_chunk)
1138                 return;
1139             pcmbuf_mix_sample = 0;
1140             obuf = pcmbuf_mix_chunk->addr;
1141             chunk_samples = pcmbuf_mix_chunk->size / 2;
1142         }
1143         sample += obuf[pcmbuf_mix_sample] >> 2;
1144         obuf[pcmbuf_mix_sample++] = clip_sample_16(sample);
1145     }
1146 }
1147
1148 void pcmbuf_crossfade_enable(bool on_off)
1149 {
1150     /* Next setting to be used, not applied now */
1151     crossfade_enabled_pending = on_off;
1152 }
1153
1154 void pcmbuf_crossfade_enable_finished(void)
1155 {
1156     /* Copy the pending setting over now */
1157     crossfade_enabled = crossfade_enabled_pending;
1158     pcmbuf_set_watermark_bytes();
1159 }
1160
1161 bool pcmbuf_is_crossfade_enabled(void)
1162 {
1163     if (global_settings.crossfade == CROSSFADE_ENABLE_SHUFFLE)
1164         return global_settings.playlist_shuffle;
1165
1166     return crossfade_enabled;
1167 }
1168
1169 /** PLAY LAST REMAINING SAMPLES AT END OF PLAYBACK
1170  *  Commit any remaining samples in the PCM buffer for playback. */
1171 void pcmbuf_play_remainder(void)
1172 {
1173     if (audiobuffer_fillpos)
1174         pcmbuf_flush_fillpos();
1175 }