rockbox/apps/pcmbuf.h
Michael Sevakis 7ad2cad173 Commit work started in FS#12153 to put timing/position information in PCM
buffer chunks.

* Samples and position indication is closely associated with audio data
  instead of compensating by a latency constant. Alleviates problems with
  using the elapsed as a track indicator where it could be off by several
  steps.

* Timing is accurate throughout track even if resampling for pitch shift,
  whereas before it updated during transition latency at the normal 1:1 rate.

* Simpler PCM buffer with a constant chunk size, no linked lists.

In converting crossfade, a minor change was made to not change the WPS until
the fade-in of the incoming track, whereas before it would change upon the
start of the fade-out of the outgoing track possibly having the WPS change
with far too much lead time.

Codec changes are to set elapsed times *before* writing next PCM frame because
 time and position data last set are saved in the next committed PCM chunk. 


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30366 a1c6a512-1295-4272-9138-f99709370657
2011-08-28 07:45:35 +00:00

83 lines
2.7 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2005 by Miika Pekkarinen
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef PCMBUF_H
#define PCMBUF_H
#include <sys/types.h>
/* Commit PCM data */
void *pcmbuf_request_buffer(int *count);
void pcmbuf_write_complete(int count, unsigned long elapsed, off_t offset);
/* Init */
size_t pcmbuf_init(unsigned char *bufend);
/* Playback */
void pcmbuf_play_start(void);
void pcmbuf_play_stop(void);
void pcmbuf_pause(bool pause);
void pcmbuf_monitor_track_change(bool monitor);
void pcmbuf_sync_position_update(void);
/* Track change origin type */
enum pcm_track_change_type
{
TRACK_CHANGE_NONE = 0, /* No track change pending */
TRACK_CHANGE_MANUAL, /* Manual change (from user) */
TRACK_CHANGE_AUTO, /* Automatic change (from codec) */
TRACK_CHANGE_END_OF_DATA, /* Expect no more data (from codec) */
};
void pcmbuf_start_track_change(enum pcm_track_change_type type);
/* Crossfade */
#ifdef HAVE_CROSSFADE
bool pcmbuf_is_crossfade_active(void);
void pcmbuf_request_crossfade_enable(int setting);
bool pcmbuf_is_same_size(void);
#else
/* Dummy functions with sensible returns */
static FORCE_INLINE bool pcmbuf_is_crossfade_active(void)
{ return false; }
static FORCE_INLINE void pcmbuf_request_crossfade_enable(bool on_off)
{ return; (void)on_off; }
static FORCE_INLINE bool pcmbuf_is_same_size(void)
{ return true; }
#endif
/* Voice */
void *pcmbuf_request_voice_buffer(int *count);
void pcmbuf_write_voice_complete(int count);
/* Debug menu, other metrics */
size_t pcmbuf_free(void);
size_t pcmbuf_get_bufsize(void);
int pcmbuf_descs(void);
int pcmbuf_used_descs(void);
unsigned int pcmbuf_get_position_key(void);
/* Misc */
void pcmbuf_fade(bool fade, bool in);
bool pcmbuf_fading(void);
void pcmbuf_soft_mode(bool shhh);
bool pcmbuf_is_lowdata(void);
void pcmbuf_set_low_latency(bool state);
#endif