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
  22 #include <stdbool.h>
  23 #include <stdio.h>
  24 #include "config.h"
  25 #include "debug.h"
  26 #include "panic.h"
  27 #include <kernel.h>
  28 #include "pcmbuf.h"
  29 #include "pcm.h"
  30 #include "logf.h"
  31 #ifndef SIMULATOR
  32 #include "cpu.h"
  33 #endif
  34 #include "system.h"
  35 #include <string.h>
  36 #include "buffer.h"
  37 #include "settings.h"
  38 #include "audio.h"
  39 #include "voice_thread.h"
  40 #include "dsp.h"
  41 #include "thread.h"
  42
  43 /* Define PCMBUF_MUTING if the codec requires muting to prevent pops */
  44 #if !defined(HAVE_UDA1380) && !defined(HAVE_TLV320) && !defined(HAVE_AS3514) \
  45     && !defined(HAVE_WM8978)
  46 #define PCMBUF_MUTING
  47 #endif
  48
  49 /* Clip sample to signed 16 bit range */
  50 static inline int32_t clip_sample_16(int32_t sample)
  51 {
  52     if ((int16_t)sample != sample)
  53         sample = 0x7fff ^ (sample >> 31);
  54     return sample;
  55 }
  56
  57 /* Keep watermark high for iPods at least (2s) */
  58 #define PCMBUF_WATERMARK     (NATIVE_FREQUENCY * 4 * 2)
  59
  60 /* Structure we can use to queue pcm chunks in memory to be played
  61  * by the driver code. */
  62 struct pcmbufdesc
  63 {
  64     void *addr;
  65     size_t size;
  66     struct pcmbufdesc* link;
  67     /* Call this when the buffer has been played */
  68     void (*callback)(void);
  69 };
  70
  71 #define PCMBUF_DESCS(bufsize) \
  72     ((bufsize) / PCMBUF_MINAVG_CHUNK)
  73 #define PCMBUF_DESCS_SIZE(bufsize) \
  74     (PCMBUF_DESCS(bufsize)*sizeof(struct pcmbufdesc))
  75
  76 /* Size of the PCM buffer. */
  77 static size_t pcmbuf_size IDATA_ATTR = 0;
  78 static char *pcmbuf_bufend IDATA_ATTR;
  79 static char *audiobuffer IDATA_ATTR;
  80 /* Current audio buffer write index. */
  81 static size_t audiobuffer_pos IDATA_ATTR;
  82 /* Amount audiobuffer_pos will be increased.*/
  83 static size_t audiobuffer_fillpos IDATA_ATTR;
  84 static char *fadebuf IDATA_ATTR;
  85 static char *voicebuf IDATA_ATTR;
  86
  87 static void (*pcmbuf_event_handler)(void) IDATA_ATTR;
  88 static void (*position_callback)(size_t size) IDATA_ATTR;
  89
  90 /* Crossfade related state */
  91 static bool crossfade_enabled;
  92 static bool crossfade_enabled_pending;
  93 static bool crossfade_mixmode;
  94 static bool crossfade_active IDATA_ATTR;
  95 static bool crossfade_init IDATA_ATTR;
  96
  97 /* Track the current location for processing crossfade */
  98 static struct pcmbufdesc *crossfade_chunk IDATA_ATTR;
  99 static size_t crossfade_sample IDATA_ATTR;
 100
 101 /* Counters for fading in new data */
 102 static size_t crossfade_fade_in_total IDATA_ATTR;
 103 static size_t crossfade_fade_in_rem IDATA_ATTR;
 104
 105 static struct pcmbufdesc *pcmbuf_read IDATA_ATTR;
 106 static struct pcmbufdesc *pcmbuf_read_end IDATA_ATTR;
 107 static struct pcmbufdesc *pcmbuf_write IDATA_ATTR;
 108 static struct pcmbufdesc *pcmbuf_write_end IDATA_ATTR;
 109 static size_t last_chunksize IDATA_ATTR;
 110
 111 static size_t pcmbuf_unplayed_bytes IDATA_ATTR;
 112 static size_t pcmbuf_watermark IDATA_ATTR;
 113
 114 static struct pcmbufdesc *pcmbuf_mix_chunk IDATA_ATTR;
 115 static size_t pcmbuf_mix_sample IDATA_ATTR;
 116
 117 static bool low_latency_mode = false;
 118 static bool pcmbuf_flush;
 119
 120 #ifdef HAVE_PRIORITY_SCHEDULING
 121 static int codec_thread_priority = PRIORITY_PLAYBACK;
 122 #endif
 123
 124 extern struct thread_entry *codec_thread_p;
 125
 126 /* Helpful macros for use in conditionals this assumes some of the above
 127  * static variable names */
 128 #define NEED_FLUSH(position) \
 129     (audiobuffer_fillpos > PCMBUF_TARGET_CHUNK || position >= pcmbuf_size)
 130 #define LOW_DATA(quarter_secs) \
 131     (pcmbuf_unplayed_bytes < NATIVE_FREQUENCY * quarter_secs)
 132
 133 static bool prepare_insert(size_t length);
 134 static void pcmbuf_under_watermark(void);
 135 static bool pcmbuf_flush_fillpos(void);
 136
 137 #define CALL_IF_EXISTS(function, args...) if (function) function(args)
 138 /* This function has 2 major logical parts (separated by brackets both for
 139  * readability and variable scoping).  The first part performs the
 140  * operastions related to finishing off the last buffer we fed to the DMA.
 141  * The second part performs the operations involved in sending a new buffer
 142  * to the DMA.  Finally the function checks the status of the buffer and
 143  * boosts if necessary */
 144 static void pcmbuf_callback(unsigned char** start, size_t* size) ICODE_ATTR;
 145 static void pcmbuf_callback(unsigned char** start, size_t* size)
 146 {
 147     {
 148         struct pcmbufdesc *pcmbuf_current = pcmbuf_read;
 149         /* Take the finished buffer out of circulation */
 150         pcmbuf_read = pcmbuf_current->link;
 151
 152         /* The buffer is finished, call the callback functions */
 153         CALL_IF_EXISTS(position_callback, last_chunksize);
 154         CALL_IF_EXISTS(pcmbuf_current->callback);
 155
 156         /* Put the finished buffer back into circulation */
 157         pcmbuf_write_end->link = pcmbuf_current;
 158         pcmbuf_write_end = pcmbuf_current;
 159
 160         /* If we've read over the mix chunk while it's still mixing there */
 161         if (pcmbuf_current == pcmbuf_mix_chunk)
 162             pcmbuf_mix_chunk = NULL;
 163         /* If we've read over the crossfade chunk while it's still fading */
 164         if (pcmbuf_current == crossfade_chunk)
 165             crossfade_chunk = pcmbuf_read;
 166     }
 167
 168     {
 169         /* Send the new buffer to the pcm */
 170         struct pcmbufdesc *pcmbuf_new = pcmbuf_read;
 171         size_t *realsize = size;
 172         unsigned char** realstart = start;
 173         if(pcmbuf_new)
 174         {
 175             size_t current_size = pcmbuf_new->size;
 176
 177             pcmbuf_unplayed_bytes -= current_size;
 178             last_chunksize = current_size;
 179             *realsize = current_size;
 180             *realstart = pcmbuf_new->addr;
 181         }
 182         else
 183         {
 184             /* No more buffers */
 185             last_chunksize = 0;
 186             *realsize = 0;
 187             *realstart = NULL;
 188             CALL_IF_EXISTS(pcmbuf_event_handler);
 189         }
 190     }
 191 }
 192
 193 void pcmbuf_set_position_callback(void (*callback)(size_t size))
 194 {
 195     position_callback = callback;
 196 }
 197
 198 static void pcmbuf_set_watermark_bytes(void)
 199 {
 200     pcmbuf_watermark = (crossfade_enabled && pcmbuf_size) ?
 201         /* If crossfading, try to keep the buffer full other than 1 second */
 202         (pcmbuf_size - (NATIVE_FREQUENCY * 4 * 1)) :
 203         /* Otherwise, just keep it above 2 second */
 204         PCMBUF_WATERMARK;
 205 }
 206
 207 /* This is really just part of pcmbuf_flush_fillpos, but is easier to keep
 208  * in a separate function for the moment */
 209 static inline void pcmbuf_add_chunk(void)
 210 {
 211     register size_t size = audiobuffer_fillpos;
 212     /* Grab the next description to write, and change the write pointer */
 213     register struct pcmbufdesc *pcmbuf_current = pcmbuf_write;
 214     pcmbuf_write = pcmbuf_current->link;
 215     /* Fill in the values in the new buffer chunk */
 216     pcmbuf_current->addr = &audiobuffer[audiobuffer_pos];
 217     pcmbuf_current->size = size;
 218     pcmbuf_current->callback = pcmbuf_event_handler;
 219     pcmbuf_current->link = NULL;
 220     /* This is single use only */
 221     pcmbuf_event_handler = NULL;
 222     if (pcmbuf_read != NULL) {
 223         if (pcmbuf_flush)
 224         {
 225             pcmbuf_write_end->link = pcmbuf_read->link;
 226             pcmbuf_read->link = pcmbuf_current;
 227             while (pcmbuf_write_end->link)
 228             {
 229                 pcmbuf_write_end = pcmbuf_write_end->link;
 230                 pcmbuf_unplayed_bytes -= pcmbuf_write_end->size;
 231             }
 232             pcmbuf_flush = false;
 233         }
 234         /* If there is already a read buffer setup, add to it */
 235         else
 236             pcmbuf_read_end->link = pcmbuf_current;
 237     } else {
 238         /* Otherwise create the buffer */
 239         pcmbuf_read = pcmbuf_current;
 240     }
 241     /* This is now the last buffer to read */
 242     pcmbuf_read_end = pcmbuf_current;
 243
 244     /* Update bytes counters */
 245     pcmbuf_unplayed_bytes += size;
 246
 247     audiobuffer_pos += size;
 248     if (audiobuffer_pos >= pcmbuf_size)
 249         audiobuffer_pos -= pcmbuf_size;
 250
 251     audiobuffer_fillpos = 0;
 252 }
 253
 254 #ifdef HAVE_PRIORITY_SCHEDULING
 255 static void boost_codec_thread(bool boost)
 256 {
 257     /* Keep voice and codec threads at the same priority or else voice
 258      * will starve if the codec thread's priority is boosted. */
 259     if (boost)
 260     {
 261         int priority = (PRIORITY_PLAYBACK - PRIORITY_PLAYBACK_MAX)*pcmbuf_unplayed_bytes
 262                           / (2*NATIVE_FREQUENCY) + PRIORITY_PLAYBACK_MAX;
 263
 264         if (priority != codec_thread_priority)
 265         {
 266             codec_thread_priority = priority;
 267             thread_set_priority(codec_thread_p, priority);
 268             voice_thread_set_priority(priority);
 269         }
 270     }
 271     else if (codec_thread_priority != PRIORITY_PLAYBACK)
 272     {
 273         thread_set_priority(codec_thread_p, PRIORITY_PLAYBACK);
 274         voice_thread_set_priority(PRIORITY_PLAYBACK);
 275         codec_thread_priority = PRIORITY_PLAYBACK;
 276     }
 277 }
 278 #endif /* HAVE_PRIORITY_SCHEDULING */
 279
 280 static void pcmbuf_under_watermark(void)
 281 {
 282     /* Only codec thread initiates boost - voice boosts the cpu when playing
 283        a clip */
 284 #ifndef SIMULATOR
 285     if (thread_get_current() == codec_thread_p)
 286 #endif /* SIMULATOR */
 287     {
 288 #ifdef HAVE_PRIORITY_SCHEDULING
 289         /* If buffer is critically low, override UI priority, else
 290            set back to the original priority. */
 291         boost_codec_thread(LOW_DATA(2) && pcm_is_playing());
 292 #endif
 293         /* Fill audio buffer by boosting cpu */
 294         trigger_cpu_boost();
 295     }
 296
 297     /* Disable crossfade if < .5s of audio */
 298     if (LOW_DATA(2))
 299     {
 300         crossfade_active = false;
 301     }
 302 }
 303
 304 void pcmbuf_set_event_handler(void (*event_handler)(void))
 305 {
 306     pcmbuf_event_handler = event_handler;
 307 }
 308
 309 unsigned int pcmbuf_get_latency(void)
 310 {
 311     /* Be careful how this calculation is rearranged, it's easy to overflow */
 312     size_t bytes = pcmbuf_unplayed_bytes + pcm_get_bytes_waiting();
 313     return bytes / 4 / (NATIVE_FREQUENCY/1000);
 314 }
 315
 316 void pcmbuf_set_low_latency(bool state)
 317 {
 318     low_latency_mode = state;
 319 }
 320
 321 bool pcmbuf_is_lowdata(void)
 322 {
 323     if (!pcm_is_playing() || pcm_is_paused() ||
 324             crossfade_init || crossfade_active)
 325         return false;
 326
 327     /* 1 seconds of buffer is low data */
 328     return LOW_DATA(4);
 329 }
 330
 331 /* Amount of bytes left in the buffer. */
 332 inline size_t pcmbuf_free(void)
 333 {
 334     if (pcmbuf_read != NULL)
 335     {
 336         void *read = pcmbuf_read->addr;
 337         void *write = &audiobuffer[audiobuffer_pos + audiobuffer_fillpos];
 338         if (read < write)
 339             return (size_t)(read - write) + pcmbuf_size;
 340         else
 341             return (size_t) (read - write);
 342     }
 343     return pcmbuf_size;
 344 }
 345
 346 bool pcmbuf_crossfade_init(bool manual_skip)
 347 {
 348     /* Can't do two crossfades at once and, no fade if pcm is off now */
 349     if (crossfade_init || crossfade_active || !pcm_is_playing())
 350     {
 351         pcmbuf_play_stop();
 352         return false;
 353     }
 354
 355     trigger_cpu_boost();
 356
 357     /* Not enough data, or crossfade disabled, flush the old data instead */
 358     if (LOW_DATA(2) || !pcmbuf_is_crossfade_enabled() || low_latency_mode)
 359     {
 360         pcmbuf_flush_fillpos();
 361         pcmbuf_flush = true;
 362         return false;
 363     }
 364
 365     /* Don't enable mix mode when skipping tracks manually. */
 366     if (manual_skip)
 367         crossfade_mixmode = false;
 368     else
 369         crossfade_mixmode = global_settings.crossfade_fade_out_mixmode;
 370
 371     crossfade_init = true;
 372
 373     return true;
 374
 375 }
 376
 377 void pcmbuf_play_stop(void)
 378 {
 379     pcm_play_stop();
 380
 381     pcmbuf_unplayed_bytes = 0;
 382     pcmbuf_mix_chunk = NULL;
 383     if (pcmbuf_read) {
 384         pcmbuf_write_end->link = pcmbuf_read;
 385         pcmbuf_write_end = pcmbuf_read_end;
 386         pcmbuf_read = pcmbuf_read_end = NULL;
 387     }
 388     audiobuffer_pos = 0;
 389     audiobuffer_fillpos = 0;
 390     crossfade_init = false;
 391     crossfade_active = false;
 392     pcmbuf_flush = false;
 393
 394 #ifdef HAVE_PRIORITY_SCHEDULING
 395     /* Can unboost the codec thread here no matter who's calling */
 396     boost_codec_thread(false);
 397 #endif
 398 }
 399
 400 int pcmbuf_used_descs(void) {
 401     struct pcmbufdesc *pcmbuf_temp = pcmbuf_read;
 402     unsigned int i = 0;
 403     while (pcmbuf_temp) {
 404         pcmbuf_temp = pcmbuf_temp->link;
 405         i++;
 406     }
 407     return i;
 408 }
 409
 410 int pcmbuf_descs(void) {
 411     return PCMBUF_DESCS(pcmbuf_size);
 412 }
 413
 414 static void pcmbuf_init_pcmbuffers(void) {
 415     struct pcmbufdesc *next = pcmbuf_write;
 416     next++;
 417     pcmbuf_write_end = pcmbuf_write;
 418     while ((void *)next < (void *)pcmbuf_bufend) {
 419         pcmbuf_write_end->link=next;
 420         pcmbuf_write_end=next;
 421         next++;
 422     }
 423 }
 424
 425 static size_t pcmbuf_get_next_required_pcmbuf_size(void)
 426 {
 427 #if MEM > 1
 428     size_t seconds = 1;
 429
 430     if (crossfade_enabled_pending)
 431         seconds += global_settings.crossfade_fade_out_delay
 432                    + global_settings.crossfade_fade_out_duration;
 433
 434     /* Buffer has to be at least 2s long. */
 435     seconds += 2;
 436     logf("pcmbuf len: %ld", seconds);
 437     return seconds * (NATIVE_FREQUENCY*4);
 438 #else
 439     return NATIVE_FREQUENCY*2;
 440 #endif
 441 }
 442
 443 static char *pcmbuf_calc_audiobuffer_ptr(size_t bufsize)
 444 {
 445     return pcmbuf_bufend - (bufsize + PCMBUF_MIX_CHUNK * 2 +
 446                PCMBUF_DESCS_SIZE(bufsize));
 447 }
 448
 449 bool pcmbuf_is_same_size(void)
 450 {
 451     if (audiobuffer == NULL)
 452         return true; /* Not set up yet even once so always */
 453
 454     size_t bufsize = pcmbuf_get_next_required_pcmbuf_size();
 455     return pcmbuf_calc_audiobuffer_ptr(bufsize) == audiobuffer;
 456 }
 457
 458 /* Initialize the pcmbuffer the structure looks like this:
 459  * ...|---------PCMBUF---------|FADEBUF|VOICEBUF|DESCS|... */
 460 size_t pcmbuf_init(unsigned char *bufend)
 461 {
 462     pcmbuf_bufend = bufend;
 463     pcmbuf_size = pcmbuf_get_next_required_pcmbuf_size();
 464     audiobuffer = pcmbuf_calc_audiobuffer_ptr(pcmbuf_size);
 465     fadebuf = &audiobuffer[pcmbuf_size];
 466     voicebuf = &fadebuf[PCMBUF_MIX_CHUNK];
 467     pcmbuf_write = (struct pcmbufdesc *)&voicebuf[PCMBUF_MIX_CHUNK];
 468
 469     pcmbuf_init_pcmbuffers();
 470
 471     position_callback = NULL;
 472     pcmbuf_event_handler = NULL;
 473
 474     pcmbuf_crossfade_enable_finished();
 475
 476     pcmbuf_play_stop();
 477
 478     return pcmbuf_bufend - audiobuffer;
 479 }
 480
 481 size_t pcmbuf_get_bufsize(void)
 482 {
 483     return pcmbuf_size;
 484 }
 485
 486 #ifdef ROCKBOX_HAS_LOGF
 487 unsigned char * pcmbuf_get_meminfo(size_t *length)
 488 {
 489     *length = pcmbuf_bufend - audiobuffer;
 490     return audiobuffer;
 491 }
 492 #endif
 493
 494 void pcmbuf_pause(bool pause)
 495 {
 496 #ifdef PCMBUF_MUTING
 497     if (pause)
 498        pcm_mute(true);
 499 #endif
 500
 501     if (pcm_is_playing())
 502         pcm_play_pause(!pause);
 503     else if (!pause)
 504         pcmbuf_play_start();
 505
 506 #ifdef PCMBUF_MUTING
 507     if (!pause)
 508         pcm_mute(false);
 509 #endif
 510     trigger_cpu_boost();
 511 }
 512
 513 /* Force playback. */
 514 void pcmbuf_play_start(void)
 515 {
 516     if (!pcm_is_playing() && pcmbuf_unplayed_bytes && pcmbuf_read != NULL)
 517     {
 518         last_chunksize = pcmbuf_read->size;
 519         pcmbuf_unplayed_bytes -= last_chunksize;
 520         pcm_play_data(pcmbuf_callback,
 521             (unsigned char *)pcmbuf_read->addr, last_chunksize);
 522     }
 523 }
 524
 525 /**
 526  * Commit samples waiting to the pcm buffer.
 527  */
 528 static bool pcmbuf_flush_fillpos(void)
 529 {
 530     if (audiobuffer_fillpos) {
 531         /* Never use the last buffer descriptor */
 532         while (pcmbuf_write == pcmbuf_write_end) {
 533             /* If this happens, something is being stupid */
 534             if (!pcm_is_playing()) {
 535                 logf("pcmbuf_flush_fillpos error");
 536                 pcmbuf_play_start();
 537             }
 538             /* Let approximately one chunk of data playback */
 539             sleep(HZ*PCMBUF_TARGET_CHUNK/(NATIVE_FREQUENCY*4));
 540         }
 541         pcmbuf_add_chunk();
 542         return true;
 543     }
 544     return false;
 545 }
 546
 547 /**
 548  * Completely process the crossfade fade out effect with current pcm buffer.
 549  */
 550 static void crossfade_process_buffer(size_t fade_in_delay,
 551         size_t fade_out_delay, size_t fade_out_rem)
 552 {
 553     if (!crossfade_mixmode)
 554     {
 555         /* Fade out the specified amount of the already processed audio */
 556         size_t total_fade_out = fade_out_rem;
 557         size_t fade_out_sample;
 558         struct pcmbufdesc *fade_out_chunk = crossfade_chunk;
 559
 560         /* Find the right chunk to start fading out */
 561         fade_out_delay += crossfade_sample * 2;
 562         while (fade_out_delay != 0 && fade_out_delay >= fade_out_chunk->size)
 563         {
 564             fade_out_delay -= fade_out_chunk->size;
 565             fade_out_chunk = fade_out_chunk->link;
 566         }
 567         /* The start sample within the chunk */
 568         fade_out_sample = fade_out_delay / 2;
 569
 570         while (fade_out_rem > 0)
 571         {
 572             /* Each 1/10 second of audio will have the same fade applied */
 573             size_t block_rem = MIN(NATIVE_FREQUENCY * 4 / 10, fade_out_rem);
 574             int factor = (fade_out_rem << 8) / total_fade_out;
 575
 576             fade_out_rem -= block_rem;
 577
 578             /* Fade this block */
 579             while (block_rem > 0 && fade_out_chunk != NULL)
 580             {
 581                 /* Fade one sample */
 582                 int16_t *buf = (int16_t *)fade_out_chunk->addr;
 583                 int32_t sample = buf[fade_out_sample];
 584                 buf[fade_out_sample++] = (sample * factor) >> 8;
 585
 586                 block_rem -= 2;
 587                 /* Move to the next chunk as needed */
 588                 if (fade_out_sample * 2 >= fade_out_chunk->size)
 589                 {
 590                     fade_out_chunk = fade_out_chunk->link;
 591                     fade_out_sample = 0;
 592                 }
 593             }
 594         }
 595     }
 596
 597     /* Find the right chunk and sample to start fading in */
 598     fade_in_delay += crossfade_sample * 2;
 599     while (fade_in_delay != 0 && fade_in_delay >= crossfade_chunk->size)
 600     {
 601         fade_in_delay -= crossfade_chunk->size;
 602         crossfade_chunk = crossfade_chunk->link;
 603     }
 604     crossfade_sample = fade_in_delay / 2;
 605     logf("process done!");
 606 }
 607
 608 /* Initializes crossfader, calculates all necessary parameters and
 609  * performs fade-out with the pcm buffer.  */
 610 static void crossfade_start(void)
 611 {
 612     size_t crossfade_rem;
 613     size_t crossfade_need;
 614     size_t fade_out_rem;
 615     size_t fade_out_delay;
 616     size_t fade_in_delay;
 617
 618     crossfade_init = false;
 619     /* Reject crossfade if less than .5s of data */
 620     if (LOW_DATA(2)) {
 621         logf("crossfade rejected");
 622         pcmbuf_play_stop();
 623         return ;
 624     }
 625
 626     logf("crossfade_start");
 627     pcmbuf_flush_fillpos();
 628     crossfade_active = true;
 629
 630     /* Initialize the crossfade buffer size to all of the buffered data that
 631      * has not yet been sent to the DMA */
 632     crossfade_rem = pcmbuf_unplayed_bytes;
 633     crossfade_chunk = pcmbuf_read->link;
 634     crossfade_sample = 0;
 635
 636     /* Get fade out delay from settings. */
 637     fade_out_delay =
 638         NATIVE_FREQUENCY * global_settings.crossfade_fade_out_delay * 4;
 639
 640     /* Get fade out duration from settings. */
 641     fade_out_rem =
 642         NATIVE_FREQUENCY * global_settings.crossfade_fade_out_duration * 4;
 643
 644     crossfade_need = fade_out_delay + fade_out_rem;
 645     /* We want only to modify the last part of the buffer. */
 646     if (crossfade_rem > crossfade_need)
 647     {
 648         size_t crossfade_extra = crossfade_rem - crossfade_need;
 649         while (crossfade_extra > crossfade_chunk->size)
 650         {
 651             crossfade_extra -= crossfade_chunk->size;
 652             crossfade_chunk = crossfade_chunk->link;
 653         }
 654         crossfade_sample = crossfade_extra / 2;
 655     }
 656     /* Truncate fade out duration if necessary. */
 657     else if (crossfade_rem < crossfade_need)
 658     {
 659         size_t crossfade_short = crossfade_need - crossfade_rem;
 660         if (fade_out_rem >= crossfade_short)
 661             fade_out_rem -= crossfade_short;
 662         else
 663         {
 664             fade_out_delay -= crossfade_short - fade_out_rem;
 665             fade_out_rem = 0;
 666         }
 667     }
 668
 669     /* Get also fade in duration and delays from settings. */
 670     crossfade_fade_in_total =
 671         NATIVE_FREQUENCY * global_settings.crossfade_fade_in_duration * 4;
 672     crossfade_fade_in_rem = crossfade_fade_in_total;
 673
 674     fade_in_delay =
 675         NATIVE_FREQUENCY * global_settings.crossfade_fade_in_delay * 4;
 676
 677     crossfade_process_buffer(fade_in_delay, fade_out_delay, fade_out_rem);
 678 }
 679
 680 /* Returns the number of bytes _NOT_ mixed */
 681 static size_t crossfade_fade_mix(int factor, const char *buf, size_t fade_rem)
 682 {
 683     const int16_t *input_buf = (const int16_t *)buf;
 684     int16_t *output_buf = (int16_t *)(crossfade_chunk->addr);
 685     int16_t *chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 686     output_buf = &output_buf[crossfade_sample];
 687     int32_t sample;
 688
 689     while (fade_rem)
 690     {
 691         /* fade left and right channel at once to keep buffer alignment */
 692         sample = *input_buf++;
 693         sample = ((sample * factor) >> 8) + *output_buf;
 694         *output_buf++ = clip_sample_16(sample);
 695
 696         sample = *input_buf++;
 697         sample = ((sample * factor) >> 8) + *output_buf;
 698         *output_buf++ = clip_sample_16(sample);
 699
 700         fade_rem -= 4; /* 2 samples, each 16 bit -> 4 bytes */
 701
 702         if (output_buf >= chunk_end)
 703         {
 704             crossfade_chunk = crossfade_chunk->link;
 705             if (!crossfade_chunk)
 706                 return fade_rem;
 707             output_buf = (int16_t *)crossfade_chunk->addr;
 708             chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 709         }
 710     }
 711     crossfade_sample = output_buf - (int16_t *)crossfade_chunk->addr;
 712     return 0;
 713 }
 714
 715 /* Returns the number of bytes _NOT_ mixed */
 716 static size_t crossfade_mix(const char *buf, size_t length)
 717 {
 718     const int16_t *input_buf = (const int16_t *)buf;
 719     int16_t *output_buf = (int16_t *)crossfade_chunk->addr;
 720     int16_t *chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 721     output_buf = &output_buf[crossfade_sample];
 722     int32_t sample;
 723
 724     while (length)
 725     {
 726         /* fade left and right channel at once to keep buffer alignment */
 727         sample = *input_buf++ + *output_buf;
 728         *output_buf++ = clip_sample_16(sample);
 729
 730         sample = *input_buf++ + *output_buf;
 731         *output_buf++ = clip_sample_16(sample);
 732
 733         length -= 4; /* 2 samples, each 16 bit -> 4 bytes */
 734
 735         if (output_buf >= chunk_end)
 736         {
 737             crossfade_chunk = crossfade_chunk->link;
 738             if (!crossfade_chunk)
 739                 return length;
 740
 741             output_buf = (int16_t *)crossfade_chunk->addr;
 742             chunk_end = SKIPBYTES(output_buf, crossfade_chunk->size);
 743         }
 744     }
 745     crossfade_sample = output_buf - (int16_t *)crossfade_chunk->addr;
 746     return 0;
 747 }
 748
 749 static void pcmbuf_flush_buffer(const char *buf, size_t length)
 750 {
 751     size_t copy_n;
 752     while (length > 0) {
 753         size_t audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 754         if (NEED_FLUSH(audiobuffer_index))
 755         {
 756             pcmbuf_flush_fillpos();
 757             audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 758         }
 759         copy_n = MIN(length, pcmbuf_size - audiobuffer_index);
 760         memcpy(&audiobuffer[audiobuffer_index], buf, copy_n);
 761         buf += copy_n;
 762         audiobuffer_fillpos += copy_n;
 763         length -= copy_n;
 764     }
 765 }
 766
 767 static void flush_crossfade(char *buf, size_t length)
 768 {
 769     if (length)
 770     {
 771         if (crossfade_fade_in_rem)
 772         {
 773             size_t samples;
 774             int16_t *input_buf;
 775
 776             /* Fade factor for this packet */
 777             int factor =
 778                 ((crossfade_fade_in_total - crossfade_fade_in_rem) << 8) /
 779                 crossfade_fade_in_total;
 780             /* Bytes to fade */
 781             size_t fade_rem = MIN(length, crossfade_fade_in_rem);
 782
 783             /* We _will_ fade this many bytes */
 784             crossfade_fade_in_rem -= fade_rem;
 785
 786             if (crossfade_chunk)
 787             {
 788                 /* Mix the data */
 789                 size_t fade_total = fade_rem;
 790                 fade_rem = crossfade_fade_mix(factor, buf, fade_rem);
 791                 length -= fade_total - fade_rem;
 792                 buf += fade_total - fade_rem;
 793                 if (!length)
 794                     return;
 795                 if (!fade_rem)
 796                     goto fade_done;
 797             }
 798
 799             samples = fade_rem / 2;
 800             input_buf = (int16_t *)buf;
 801             /* Fade remaining samples in place */
 802             while (samples)
 803             {
 804                 int32_t sample = *input_buf;
 805                 *input_buf++ = (sample * factor) >> 8;
 806                 samples--;
 807             }
 808         }
 809
 810 fade_done:
 811         if (crossfade_chunk)
 812         {
 813             /* Mix the data */
 814             size_t mix_total = length;
 815             length = crossfade_mix(buf, length);
 816             buf += mix_total - length;
 817             if (!length)
 818                 return;
 819         }
 820
 821         /* Flush samples to the buffer */
 822         while (!prepare_insert(length))
 823             sleep(1);
 824         pcmbuf_flush_buffer(buf, length);
 825     }
 826
 827 }
 828
 829 static bool prepare_insert(size_t length)
 830 {
 831     if (low_latency_mode)
 832     {
 833         /* 1/4s latency. */
 834         if (pcmbuf_unplayed_bytes > NATIVE_FREQUENCY * 4 / 2
 835             && pcm_is_playing())
 836             return false;
 837     }
 838
 839     /* Need to save PCMBUF_MIN_CHUNK to prevent wrapping overwriting */
 840     if (pcmbuf_free() < length + PCMBUF_MIN_CHUNK)
 841         return false;
 842
 843     if (!pcm_is_playing())
 844     {
 845         trigger_cpu_boost();
 846
 847         /* Pre-buffer 1s. */
 848 #if MEM <= 1
 849         if (!LOW_DATA(1))
 850 #else
 851         if (!LOW_DATA(4))
 852 #endif
 853         {
 854             logf("pcm starting");
 855             if (!(audio_status() & AUDIO_STATUS_PAUSE))
 856                 pcmbuf_play_start();
 857         }
 858     }
 859     else if (pcmbuf_unplayed_bytes <= pcmbuf_watermark)
 860         pcmbuf_under_watermark();
 861
 862     return true;
 863 }
 864
 865 void* pcmbuf_request_buffer(int *count)
 866 {
 867     if (crossfade_init)
 868         crossfade_start();
 869
 870     if (crossfade_active) {
 871         *count = MIN(*count, PCMBUF_MIX_CHUNK/4);
 872         return fadebuf;
 873     }
 874     else
 875     {
 876         if(prepare_insert(*count << 2))
 877         {
 878             size_t audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
 879             if (pcmbuf_size - audiobuffer_index >= PCMBUF_MIN_CHUNK)
 880             {
 881                 /* Usual case, there's space here */
 882                 return &audiobuffer[audiobuffer_index];
 883             }
 884             else
 885             {
 886                 /* Flush and wrap the buffer */
 887                 pcmbuf_flush_fillpos();
 888                 audiobuffer_pos = 0;
 889                 return &audiobuffer[0];
 890             }
 891         }
 892         else
 893         {
 894             return NULL;
 895         }
 896     }
 897 }
 898
 899 void * pcmbuf_request_voice_buffer(int *count)
 900 {
 901     /* A get-it-to-work-for-now hack (audio status could change by
 902        completion) */
 903     if (audio_status() & AUDIO_STATUS_PLAY)
 904     {
 905         if (pcmbuf_read == NULL)
 906         {
 907             return NULL;
 908         }
 909         else if (pcmbuf_usage() >= 10 && pcmbuf_mix_free() >= 30 &&
 910                  (pcmbuf_mix_chunk || pcmbuf_read->link))
 911         {
 912             *count = MIN(*count, PCMBUF_MIX_CHUNK/4);
 913             return voicebuf;
 914         }
 915         else
 916         {
 917             return NULL;
 918         }
 919     }
 920     else
 921     {
 922         return pcmbuf_request_buffer(count);
 923     }
 924 }
 925
 926 bool pcmbuf_is_crossfade_active(void)
 927 {
 928     return crossfade_active || crossfade_init;
 929 }
 930
 931 void pcmbuf_write_complete(int count)
 932 {
 933     size_t length = (size_t)(unsigned int)count << 2;
 934
 935     if (crossfade_active)
 936     {
 937         flush_crossfade(fadebuf, length);
 938         if (!(crossfade_fade_in_rem || crossfade_chunk))
 939             crossfade_active = false;
 940     }
 941     else
 942     {
 943         audiobuffer_fillpos += length;
 944
 945         if (NEED_FLUSH(audiobuffer_pos + audiobuffer_fillpos))
 946             pcmbuf_flush_fillpos();
 947     }
 948 }
 949
 950 #if 0
 951 bool pcmbuf_insert_buffer(char *buf, int count)
 952 {
 953     size_t length = (size_t)(unsigned int)count << 2;
 954
 955     if (crossfade_active)
 956     {
 957         flush_crossfade(buf, length);
 958         if (!(crossfade_fade_in_rem || crossfade_chunk))
 959             crossfade_active = false;
 960     }
 961     else
 962     {
 963         if (!prepare_insert(length))
 964             return false;
 965         pcmbuf_flush_buffer(buf, length);
 966     }
 967     return true;
 968 }
 969 #endif
 970
 971 /* Generates a constant square wave sound with a given frequency
 972    in Hertz for a duration in milliseconds. */
 973 void pcmbuf_beep(unsigned int frequency, size_t duration, int amplitude)
 974 {
 975     unsigned int count = 0;
 976     unsigned int i;
 977     unsigned int interval = NATIVE_FREQUENCY / frequency;
 978     unsigned int samples = NATIVE_FREQUENCY / 1000 * duration;
 979     int32_t sample;
 980     int16_t *bufstart;
 981     int16_t *bufptr;
 982     int16_t *pcmbuf_end = (int16_t *)fadebuf;
 983     bool mix = pcmbuf_read != NULL && pcmbuf_read->link != NULL;
 984
 985     /* Find the insertion point and set bufstart to the start of it */
 986     if (mix)
 987     {
 988         /* Get the next chunk */
 989         char *pcmbuf_mix_buf = pcmbuf_read->link->addr;
 990         /* Give 1/8s clearance. */
 991         bufstart = (int16_t *)&pcmbuf_mix_buf[NATIVE_FREQUENCY * 4 / 8];
 992     }
 993     else
 994     {
 995         /* Use audiobuffer */
 996         bufstart = (int16_t *)audiobuffer;
 997     }
 998
 999     /* Mix square wave into buffer */
1000     bufptr = bufstart;
1001     for (i = 0; i < samples; ++i)
1002     {
1003         sample = mix ? *bufptr : 0;
1004         *bufptr++ = clip_sample_16(sample + amplitude);
1005         if (bufptr > pcmbuf_end)
1006             bufptr = (int16_t *)audiobuffer;
1007         sample = mix ? *bufptr : 0;
1008         *bufptr++ = clip_sample_16(sample + amplitude);
1009         if (bufptr > pcmbuf_end)
1010             bufptr = (int16_t *)audiobuffer;
1011
1012         /* Toggle square wave edge */
1013         if (++count >= interval)
1014         {
1015             count = 0;
1016             amplitude = -amplitude;
1017         }
1018     }
1019
1020     /* Kick off playback if required */
1021     if (!pcm_is_playing())
1022     {
1023         pcm_play_data(NULL, (unsigned char *)bufstart, samples * 4);
1024     }
1025 }
1026
1027
1028 /* Returns pcm buffer usage in percents (0 to 100). */
1029 int pcmbuf_usage(void)
1030 {
1031     return pcmbuf_unplayed_bytes * 100 / pcmbuf_size;
1032 }
1033
1034 int pcmbuf_mix_free(void)
1035 {
1036     if (pcmbuf_mix_chunk)
1037     {
1038         size_t my_mix_end =
1039             (size_t)&((int16_t *)pcmbuf_mix_chunk->addr)[pcmbuf_mix_sample];
1040         size_t my_write_pos = (size_t)&audiobuffer[audiobuffer_pos];
1041         if (my_write_pos < my_mix_end)
1042             my_write_pos += pcmbuf_size;
1043         return (my_write_pos - my_mix_end) * 100 / pcmbuf_unplayed_bytes;
1044     }
1045     return 100;
1046 }
1047
1048 void pcmbuf_write_voice_complete(int count)
1049 {
1050     /* A get-it-to-work-for-now hack (audio status could have changed) */
1051     if (!(audio_status() & AUDIO_STATUS_PLAY))
1052     {
1053         pcmbuf_write_complete(count);
1054         return;
1055     }
1056
1057     int16_t *ibuf = (int16_t *)voicebuf;
1058     int16_t *obuf;
1059     size_t chunk_samples;
1060
1061     if (pcmbuf_mix_chunk == NULL && pcmbuf_read != NULL)
1062     {
1063         pcmbuf_mix_chunk = pcmbuf_read->link;
1064         /* Start 1/8s into the next chunk */
1065         pcmbuf_mix_sample = NATIVE_FREQUENCY * 4 / 16;
1066     }
1067
1068     if (!pcmbuf_mix_chunk)
1069         return;
1070
1071     obuf = (int16_t *)pcmbuf_mix_chunk->addr;
1072     chunk_samples = pcmbuf_mix_chunk->size / sizeof (int16_t);
1073
1074     count <<= 1;
1075
1076     while (count-- > 0)
1077     {
1078         int32_t sample = *ibuf++;
1079
1080         if (pcmbuf_mix_sample >= chunk_samples)
1081         {
1082             pcmbuf_mix_chunk = pcmbuf_mix_chunk->link;
1083             if (!pcmbuf_mix_chunk)
1084                 return;
1085             pcmbuf_mix_sample = 0;
1086             obuf = pcmbuf_mix_chunk->addr;
1087             chunk_samples = pcmbuf_mix_chunk->size / 2;
1088         }
1089         sample += obuf[pcmbuf_mix_sample] >> 2;
1090         obuf[pcmbuf_mix_sample++] = clip_sample_16(sample);
1091     }
1092 }
1093
1094 void pcmbuf_crossfade_enable(bool on_off)
1095 {
1096 #if MEM > 1
1097     /* Next setting to be used, not applied now */
1098     crossfade_enabled_pending = on_off;
1099 #endif
1100     (void)on_off;
1101 }
1102
1103 void pcmbuf_crossfade_enable_finished(void)
1104 {
1105     /* Copy the pending setting over now */
1106     crossfade_enabled = crossfade_enabled_pending;
1107     pcmbuf_set_watermark_bytes();
1108 }
1109
1110 bool pcmbuf_is_crossfade_enabled(void)
1111 {
1112     if (global_settings.crossfade == CROSSFADE_ENABLE_SHUFFLE)
1113         return global_settings.playlist_shuffle;
1114
1115     return crossfade_enabled;
1116 }