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     int32_t sample;
 691
 692     while (fade_rem)
 693     {
 694         /* fade left and right channel at once to keep buffer alignment */
 695         sample = *input_buf++;
 696         sample = ((sample * factor) >> 8) + *output_buf;
 697         *output_buf++ = clip_sample_16(sample);
 698
 699         sample = *input_buf++;
 700         sample = ((sample * factor) >> 8) + *output_buf;
 701         *output_buf++ = clip_sample_16(sample);
 702
 703         fade_rem -= 4; /* 2 samples, each 16 bit -> 4 bytes */
 704
 705         if (output_buf >= chunk_end)
 706         {
 707             crossfade_chunk = crossfade_chunk->link;
 708             if (!crossfade_chunk)
 709                 return fade_rem;
 710             output_buf = (int16_t *)crossfade_chunk->addr;
 711             chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 712         }
 713     }
 714     crossfade_sample = output_buf - (int16_t *)crossfade_chunk->addr;
 715     return 0;
 716 }
 717
 718 /* Returns the number of bytes _NOT_ mixed */
 719 static size_t crossfade_mix(const char *buf, size_t length)
 720 {
 721     const int16_t *input_buf = (const int16_t *)buf;
 722     int16_t *output_buf = (int16_t *)crossfade_chunk->addr;
 723     int16_t *chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 724     output_buf = &output_buf[crossfade_sample];
 725     int32_t sample;
 726
 727     while (length)
 728     {
 729         /* fade left and right channel at once to keep buffer alignment */
 730         sample = *input_buf++ + *output_buf;
 731         *output_buf++ = clip_sample_16(sample);
 732
 733         sample = *input_buf++ + *output_buf;
 734         *output_buf++ = clip_sample_16(sample);
 735
 736         length -= 4; /* 2 samples, each 16 bit -> 4 bytes */
 737
 738         if (output_buf >= chunk_end)
 739         {
 740             crossfade_chunk = crossfade_chunk->link;
 741             if (!crossfade_chunk)
 742                 return length;
 743
 744             output_buf = (int16_t *)crossfade_chunk->addr;
 745             chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 746         }
 747     }
 748     crossfade_sample = output_buf - (int16_t *)crossfade_chunk->addr;
 749     return 0;
 750 }
 751
 752 static void pcmbuf_flush_buffer(const char *buf, size_t length)
 753 {
 754     size_t copy_n;
 755     while (length > 0) {
 756         size_t audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 757         if (NEED_FLUSH(audiobuffer_index))
 758         {
 759             pcmbuf_flush_fillpos();
 760             audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 761         }
 762         copy_n = MIN(length, pcmbuf_size - audiobuffer_index);
 763         memcpy(&audiobuffer[audiobuffer_index], buf, copy_n);
 764         buf += copy_n;
 765         audiobuffer_fillpos += copy_n;
 766         length -= copy_n;
 767     }
 768 }
 769
 770 static void flush_crossfade(char *buf, size_t length)
 771 {
 772     if (length)
 773     {
 774         if (crossfade_fade_in_rem)
 775         {
 776             size_t samples;
 777             int16_t *input_buf;
 778
 779             /* Fade factor for this packet */
 780             int factor =
 781                 ((crossfade_fade_in_total - crossfade_fade_in_rem) << 8) /
 782                 crossfade_fade_in_total;
 783             /* Bytes to fade */
 784             size_t fade_rem = MIN(length, crossfade_fade_in_rem);
 785
 786             /* We _will_ fade this many bytes */
 787             crossfade_fade_in_rem -= fade_rem;
 788
 789             if (crossfade_chunk)
 790             {
 791                 /* Mix the data */
 792                 size_t fade_total = fade_rem;
 793                 fade_rem = crossfade_fade_mix(factor, buf, fade_rem);
 794                 length -= fade_total - fade_rem;
 795                 buf += fade_total - fade_rem;
 796                 if (!length)
 797                     return;
 798                 if (!fade_rem)
 799                     goto fade_done;
 800             }
 801
 802             samples = fade_rem / 2;
 803             input_buf = (int16_t *)buf;
 804             /* Fade remaining samples in place */
 805             while (samples)
 806             {
 807                 int32_t sample = *input_buf;
 808                 *input_buf++ = (sample * factor) >> 8;
 809                 samples--;
 810             }
 811         }
 812
 813 fade_done:
 814         if (crossfade_chunk)
 815         {
 816             /* Mix the data */
 817             size_t mix_total = length;
 818             length = crossfade_mix(buf, length);
 819             buf += mix_total - length;
 820             if (!length)
 821                 return;
 822         }
 823
 824         /* Flush samples to the buffer */
 825         while (!prepare_insert(length))
 826             sleep(1);
 827         pcmbuf_flush_buffer(buf, length);
 828     }
 829
 830 }
 831
 832 static bool prepare_insert(size_t length)
 833 {
 834     if (low_latency_mode)
 835     {
 836         /* 1/4s latency. */
 837         if (pcmbuf_unplayed_bytes > NATIVE_FREQUENCY * 4 / 2
 838             && pcm_is_playing())
 839             return false;
 840     }
 841
 842     /* Need to save PCMBUF_MIN_CHUNK to prevent wrapping overwriting */
 843     if (pcmbuf_free() < length + PCMBUF_MIN_CHUNK)
 844         return false;
 845
 846     if (!pcm_is_playing())
 847     {
 848         trigger_cpu_boost();
 849
 850         /* Pre-buffer 1s. */
 851 #if MEM <= 1
 852         if (!LOW_DATA(1))
 853 #else
 854         if (!LOW_DATA(4))
 855 #endif
 856         {
 857             logf("pcm starting");
 858             if (!(audio_status() & AUDIO_STATUS_PAUSE))
 859                 pcmbuf_play_start();
 860         }
 861     }
 862     else if (pcmbuf_unplayed_bytes <= pcmbuf_watermark)
 863         pcmbuf_under_watermark();
 864
 865     return true;
 866 }
 867
 868 void* pcmbuf_request_buffer(int *count)
 869 {
 870     if (crossfade_init)
 871         crossfade_start();
 872
 873     if (crossfade_active) {
 874         *count = MIN(*count, PCMBUF_MIX_CHUNK/4);
 875         return fadebuf;
 876     }
 877     else
 878     {
 879         if(prepare_insert(*count << 2))
 880         {
 881             size_t audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 882             if (pcmbuf_size - audiobuffer_index >= PCMBUF_MIN_CHUNK)
 883             {
 884                 /* Usual case, there's space here */
 885                 return &audiobuffer[audiobuffer_index];
 886             }
 887             else
 888             {
 889                 /* Flush and wrap the buffer */
 890                 pcmbuf_flush_fillpos();
 891                 audiobuffer_pos = 0;
 892                 return &audiobuffer[0];
 893             }
 894         }
 895         else
 896         {
 897             return NULL;
 898         }
 899     }
 900 }
 901
 902 void * pcmbuf_request_voice_buffer(int *count)
 903 {
 904     /* A get-it-to-work-for-now hack (audio status could change by
 905        completion) */
 906     if (audio_status() & AUDIO_STATUS_PLAY)
 907     {
 908         if (pcmbuf_read == NULL)
 909         {
 910             return NULL;
 911         }
 912         else if (pcmbuf_usage() >= 10 && pcmbuf_mix_free() >= 30 &&
 913                  (pcmbuf_mix_chunk || pcmbuf_read->link))
 914         {
 915             *count = MIN(*count, PCMBUF_MIX_CHUNK/4);
 916             return voicebuf;
 917         }
 918         else
 919         {
 920             return NULL;
 921         }
 922     }
 923     else
 924     {
 925         return pcmbuf_request_buffer(count);
 926     }
 927 }
 928
 929 bool pcmbuf_is_crossfade_active(void)
 930 {
 931     return crossfade_active || crossfade_init;
 932 }
 933
 934 void pcmbuf_write_complete(int count)
 935 {
 936     size_t length = (size_t)(unsigned int)count << 2;
 937
 938     if (crossfade_active)
 939     {
 940         flush_crossfade(fadebuf, length);
 941         if (!(crossfade_fade_in_rem || crossfade_chunk))
 942             crossfade_active = false;
 943     }
 944     else
 945     {
 946         audiobuffer_fillpos += length;
 947
 948         if (NEED_FLUSH(audiobuffer_pos + audiobuffer_fillpos))
 949             pcmbuf_flush_fillpos();
 950     }
 951 }
 952
 953 #if 0
 954 bool pcmbuf_insert_buffer(char *buf, int count)
 955 {
 956     size_t length = (size_t)(unsigned int)count << 2;
 957
 958     if (crossfade_active)
 959     {
 960         flush_crossfade(buf, length);
 961         if (!(crossfade_fade_in_rem || crossfade_chunk))
 962             crossfade_active = false;
 963     }
 964     else
 965     {
 966         if (!prepare_insert(length))
 967             return false;
 968         pcmbuf_flush_buffer(buf, length);
 969     }
 970     return true;
 971 }
 972 #endif
 973
 974 /* Generates a constant square wave sound with a given frequency
 975    in Hertz for a duration in milliseconds. */
 976 void pcmbuf_beep(unsigned int frequency, size_t duration, int amplitude)
 977 {
 978     unsigned int count = 0;
 979     unsigned int i;
 980     unsigned int interval = NATIVE_FREQUENCY / frequency;
 981     unsigned int samples = NATIVE_FREQUENCY / 1000 * duration;
 982     int32_t sample;
 983     int16_t *bufstart;
 984     int16_t *bufptr;
 985     int16_t *pcmbuf_end = (int16_t *)fadebuf;
 986     bool mix = pcmbuf_read != NULL && pcmbuf_read->link != NULL;
 987
 988     /* Find the insertion point and set bufstart to the start of it */
 989     if (mix)
 990     {
 991         /* Get the next chunk */
 992         char *pcmbuf_mix_buf = pcmbuf_read->link->addr;
 993         /* Give 1/8s clearance. */
 994         bufstart = (int16_t *)&pcmbuf_mix_buf[NATIVE_FREQUENCY * 4 / 8];
 995     }
 996     else
 997     {
 998         /* Use audiobuffer */
 999         bufstart = (int16_t *)audiobuffer;
1000     }
1001
1002     /* Mix square wave into buffer */
1003     bufptr = bufstart;
1004     for (i = 0; i < samples; ++i)
1005     {
1006         sample = mix ? *bufptr : 0;
1007         *bufptr++ = clip_sample_16(sample + amplitude);
1008         if (bufptr > pcmbuf_end)
1009             bufptr = (int16_t *)audiobuffer;
1010         sample = mix ? *bufptr : 0;
1011         *bufptr++ = clip_sample_16(sample + amplitude);
1012         if (bufptr > pcmbuf_end)
1013             bufptr = (int16_t *)audiobuffer;
1014
1015         /* Toggle square wave edge */
1016         if (++count >= interval)
1017         {
1018             count = 0;
1019             amplitude = -amplitude;
1020         }
1021     }
1022
1023     /* Kick off playback if required */
1024     if (!pcm_is_playing())
1025     {
1026         pcm_play_data(NULL, (unsigned char *)bufstart, samples * 4);
1027     }
1028 }
1029
1030
1031 /* Returns pcm buffer usage in percents (0 to 100). */
1032 int pcmbuf_usage(void)
1033 {
1034     return pcmbuf_unplayed_bytes * 100 / pcmbuf_size;
1035 }
1036
1037 int pcmbuf_mix_free(void)
1038 {
1039     if (pcmbuf_mix_chunk)
1040     {
1041         size_t my_mix_end =
1042             (size_t)&((int16_t *)pcmbuf_mix_chunk->addr)[pcmbuf_mix_sample];
1043         size_t my_write_pos = (size_t)&audiobuffer[audiobuffer_pos];
1044         if (my_write_pos < my_mix_end)
1045             my_write_pos += pcmbuf_size;
1046         return (my_write_pos - my_mix_end) * 100 / pcmbuf_unplayed_bytes;
1047     }
1048     return 100;
1049 }
1050
1051 void pcmbuf_write_voice_complete(int count)
1052 {
1053     /* A get-it-to-work-for-now hack (audio status could have changed) */
1054     if (!(audio_status() & AUDIO_STATUS_PLAY))
1055     {
1056         pcmbuf_write_complete(count);
1057         return;
1058     }
1059
1060     int16_t *ibuf = (int16_t *)voicebuf;
1061     int16_t *obuf;
1062     size_t chunk_samples;
1063
1064     if (pcmbuf_mix_chunk == NULL && pcmbuf_read != NULL)
1065     {
1066         pcmbuf_mix_chunk = pcmbuf_read->link;
1067         /* Start 1/8s into the next chunk */
1068         pcmbuf_mix_sample = NATIVE_FREQUENCY * 4 / 16;
1069     }
1070
1071     if (!pcmbuf_mix_chunk)
1072         return;
1073
1074     obuf = (int16_t *)pcmbuf_mix_chunk->addr;
1075     chunk_samples = pcmbuf_mix_chunk->size / sizeof (int16_t);
1076
1077     count <<= 1;
1078
1079     while (count-- > 0)
1080     {
1081         int32_t sample = *ibuf++;
1082
1083         if (pcmbuf_mix_sample >= chunk_samples)
1084         {
1085             pcmbuf_mix_chunk = pcmbuf_mix_chunk->link;
1086             if (!pcmbuf_mix_chunk)
1087                 return;
1088             pcmbuf_mix_sample = 0;
1089             obuf = pcmbuf_mix_chunk->addr;
1090             chunk_samples = pcmbuf_mix_chunk->size / 2;
1091         }
1092         sample += obuf[pcmbuf_mix_sample] >> 2;
1093         obuf[pcmbuf_mix_sample++] = clip_sample_16(sample);
1094     }
1095 }
1096
1097 void pcmbuf_crossfade_enable(bool on_off)
1098 {
1099 #if MEM > 1
1100     /* Next setting to be used, not applied now */
1101     crossfade_enabled_pending = on_off;
1102 #endif
1103     (void)on_off;
1104 }
1105
1106 void pcmbuf_crossfade_enable_finished(void)
1107 {
1108     /* Copy the pending setting over now */
1109     crossfade_enabled = crossfade_enabled_pending;
1110     pcmbuf_set_watermark_bytes();
1111 }
1112
1113 bool pcmbuf_is_crossfade_enabled(void)
1114 {
1115     if (global_settings.crossfade == CROSSFADE_ENABLE_SHUFFLE)
1116         return global_settings.playlist_shuffle;
1117
1118     return crossfade_enabled;
1119 }