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rockbox/apps/pcmbuf.c
Michael Sevakis 662f7576bf Fix a bug in pcmbuf.c when doing offset with modulus. 
Causes the track change to go in the wrong buffer (and even be missed
by playback) if the current descriptor for the write index is descriptor
0 because the offset used is "-1" upon track change.

Got nailed by implicit conversion of the % operator dividend to unsigned.

Change-Id: I32538db801ac9d790c8b1b5bd041b09ad4b64d2e
2013-06-28 02:17:58 -04:00

1333 lines
37 KiB
C
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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2005 by Miika Pekkarinen
* Copyright (C) 2011 by Michael Sevakis
*
* 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.
*
****************************************************************************/
#include <stdio.h>
#include "config.h"
#include "system.h"
#include "debug.h"
#include <kernel.h>
#include "pcm.h"
#include "pcm_mixer.h"
#include "pcmbuf.h"
#include "dsp-util.h"
#include "playback.h"
#include "codec_thread.h"
/* Define LOGF_ENABLE to enable logf output in this file */
/*#define LOGF_ENABLE*/
#include "logf.h"
#if (CONFIG_PLATFORM & PLATFORM_NATIVE)
#include "cpu.h"
#endif
#include "settings.h"
#include "audio.h"
#include "voice_thread.h"
#include "dsp_core.h"
/* This is the target fill size of chunks on the pcm buffer
Can be any number of samples but power of two sizes make for faster and
smaller math - must be < 65536 bytes */
#define PCMBUF_CHUNK_SIZE 8192u
/* Small guard buf to give decent space near end */
#define PCMBUF_GUARD_SIZE (PCMBUF_CHUNK_SIZE / 8)
/* Mnemonics for common data commit thresholds */
#define COMMIT_CHUNKS PCMBUF_CHUNK_SIZE
#define COMMIT_ALL_DATA 1u
/* Size of the crossfade buffer where codec data is written to be faded
on commit */
#define CROSSFADE_BUFSIZE PCMBUF_CHUNK_SIZE
/* Maximum contiguous space that PCM buffer will allow (to avoid excessive
draining between inserts and observe low-latency mode) */
#define PCMBUF_MAX_BUFFER (PCMBUF_CHUNK_SIZE * 4)
/* Forced buffer insert constraint can thus be from 1KB to 32KB using 8KB
chunks */
/* Return data level in 1/4-second increments */
#define DATA_LEVEL(quarter_secs) (NATIVE_FREQUENCY * (quarter_secs))
/* Number of bytes played per second:
(sample rate * 2 channels * 2 bytes/sample) */
#define BYTERATE (NATIVE_FREQUENCY * 4)
#if MEMORYSIZE > 2
/* Keep watermark high for large memory target - at least (2s) */
#define PCMBUF_WATERMARK (BYTERATE * 2)
#define MIN_BUFFER_SIZE (BYTERATE * 3)
/* 1 seconds of buffer is low data */
#define LOW_DATA DATA_LEVEL(4)
#else
#define PCMBUF_WATERMARK (BYTERATE / 4) /* 0.25 seconds */
#define MIN_BUFFER_SIZE (BYTERATE * 1)
/* under watermark is low data */
#define LOW_DATA pcmbuf_watermark
#endif
/* Describes each audio packet - keep it small since there are many of them */
struct chunkdesc
{
uint16_t size; /* Actual size (0 < size <= PCMBUF_CHUNK_SIZE) */
uint8_t is_end; /* Flag indicating end of track */
uint8_t pos_key; /* Who put the position info in (0 = undefined) */
unsigned long elapsed; /* Elapsed time to use */
off_t offset; /* Offset to use */
};
/* General PCM buffer data */
#define INVALID_BUF_INDEX ((size_t)0 - (size_t)1)
static void *pcmbuf_buffer;
static void *pcmbuf_guardbuf;
static size_t pcmbuf_size;
static struct chunkdesc *pcmbuf_descriptors;
static unsigned int pcmbuf_desc_count;
static unsigned int position_key = 1;
static size_t chunk_ridx;
static size_t chunk_widx;
static size_t pcmbuf_bytes_waiting;
static struct chunkdesc *current_desc;
/* Only written if HAVE_CROSSFADE */
static size_t pcmbuf_watermark = PCMBUF_WATERMARK;
static bool low_latency_mode = false;
static bool pcmbuf_sync_position = false;
/* Fade effect */
static unsigned int fade_vol = MIX_AMP_UNITY;
static enum
{
PCM_NOT_FADING = 0,
PCM_FADING_IN,
PCM_FADING_OUT,
} fade_state = PCM_NOT_FADING;
static bool fade_out_complete = false;
/* Voice */
static bool soft_mode = false;
#ifdef HAVE_CROSSFADE
/* Crossfade buffer */
static void *crossfade_buffer;
/* Crossfade related state */
static int crossfade_setting;
static int crossfade_enable_request;
static bool crossfade_mixmode;
static bool crossfade_auto_skip;
static enum
{
CROSSFADE_INACTIVE = 0,
CROSSFADE_TRACK_CHANGE_STARTED,
CROSSFADE_ACTIVE,
} crossfade_status = CROSSFADE_INACTIVE;
/* Track the current location for processing crossfade */
static size_t crossfade_index;
/* Counters for fading in new data */
static size_t crossfade_fade_in_total;
static size_t crossfade_fade_in_rem;
/* Defines for operations on position info when mixing/fading -
passed in offset parameter */
enum
{
MIXFADE_KEEP_POS = -1, /* Keep position info in chunk */
MIXFADE_NULLIFY_POS = -2, /* Ignore position info in chunk */
/* Positive values cause stamping/restamping */
};
static void crossfade_start(void);
static void write_to_crossfade(size_t size, unsigned long elapsed,
off_t offset);
static void pcmbuf_finish_crossfade_enable(void);
#endif /* HAVE_CROSSFADE */
/* Thread */
#ifdef HAVE_PRIORITY_SCHEDULING
static int codec_thread_priority = PRIORITY_PLAYBACK;
#endif
/* Callbacks into playback.c */
extern void audio_pcmbuf_position_callback(unsigned long elapsed,
off_t offset, unsigned int key);
extern void audio_pcmbuf_track_change(bool pcmbuf);
extern bool audio_pcmbuf_may_play(void);
extern void audio_pcmbuf_sync_position(void);
/**************************************/
/* Return number of commited bytes in buffer (committed chunks count as
a full chunk even if only partially filled) */
static size_t pcmbuf_unplayed_bytes(void)
{
size_t ridx = chunk_ridx;
size_t widx = chunk_widx;
if (ridx > widx)
widx += pcmbuf_size;
return widx - ridx;
}
/* Returns TRUE if amount of data is under the target fill size */
static bool pcmbuf_data_critical(void)
{
return pcmbuf_unplayed_bytes() < LOW_DATA;
}
/* Return the next PCM chunk in the PCM buffer given a byte index into it */
static size_t index_next(size_t index)
{
index = ALIGN_DOWN(index + PCMBUF_CHUNK_SIZE, PCMBUF_CHUNK_SIZE);
if (index >= pcmbuf_size)
index -= pcmbuf_size;
return index;
}
/* Convert a byte offset in the PCM buffer into a pointer in the buffer */
static FORCE_INLINE void * index_buffer(size_t index)
{
return pcmbuf_buffer + index;
}
/* Convert a pointer in the buffer into an index offset */
static FORCE_INLINE size_t buffer_index(void *p)
{
return (uintptr_t)p - (uintptr_t)pcmbuf_buffer;
}
/* Return a chunk descriptor for a byte index in the buffer */
static struct chunkdesc * index_chunkdesc(size_t index)
{
return &pcmbuf_descriptors[index / PCMBUF_CHUNK_SIZE];
}
/* Return a chunk descriptor for a byte index in the buffer, offset by 'offset'
chunks */
static struct chunkdesc * index_chunkdesc_offs(size_t index, int offset)
{
int i = index / PCMBUF_CHUNK_SIZE;
if (offset != 0)
{
i = (i + offset) % (int)pcmbuf_desc_count;
/* remainder => modulus */
if (i < 0)
i += pcmbuf_desc_count;
}
return &pcmbuf_descriptors[i];
}
/** Accept new PCM data */
/* Split the uncommitted data as needed into chunks, stopping when uncommitted
data is below the threshold */
static void commit_chunks(size_t threshold)
{
size_t index = chunk_widx;
size_t end_index = index + pcmbuf_bytes_waiting;
/* Copy to the beginning of the buffer all data that must wrap */
if (end_index > pcmbuf_size)
memcpy(pcmbuf_buffer, pcmbuf_guardbuf, end_index - pcmbuf_size);
struct chunkdesc *desc = index_chunkdesc(index);
do
{
size_t size = MIN(pcmbuf_bytes_waiting, PCMBUF_CHUNK_SIZE);
pcmbuf_bytes_waiting -= size;
/* Fill in the values in the new buffer chunk */
desc->size = (uint16_t)size;
/* Advance the current write chunk and make it available to the
PCM callback */
chunk_widx = index = index_next(index);
desc = index_chunkdesc(index);
/* Reset it before using it */
desc->is_end = 0;
desc->pos_key = 0;
}
while (pcmbuf_bytes_waiting >= threshold);
}
/* If uncommitted data count is above or equal to the threshold, commit it */
static FORCE_INLINE void commit_if_needed(size_t threshold)
{
if (pcmbuf_bytes_waiting >= threshold)
commit_chunks(threshold);
}
/* Place positioning information in the chunk */
static void stamp_chunk(struct chunkdesc *desc, unsigned long elapsed,
off_t offset)
{
/* One-time stamping of a given chunk by the same track - new track may
overwrite */
unsigned int key = position_key;
if (desc->pos_key != key)
{
desc->pos_key = key;
desc->elapsed = elapsed;
desc->offset = offset;
}
}
/* Set priority of the codec thread */
#ifdef HAVE_PRIORITY_SCHEDULING
/*
* expects pcm_fill_state in tenth-% units (e.g. full pcm buffer is 10) */
static void boost_codec_thread(int pcm_fill_state)
{
static const int8_t prios[11] =
{
PRIORITY_PLAYBACK_MAX, /* 0 - 10% */
PRIORITY_PLAYBACK_MAX+1, /* 10 - 20% */
PRIORITY_PLAYBACK_MAX+3, /* 20 - 30% */
PRIORITY_PLAYBACK_MAX+5, /* 30 - 40% */
PRIORITY_PLAYBACK_MAX+7, /* 40 - 50% */
PRIORITY_PLAYBACK_MAX+8, /* 50 - 60% */
PRIORITY_PLAYBACK_MAX+9, /* 60 - 70% */
/* raising priority above 70% shouldn't be needed */
PRIORITY_PLAYBACK, /* 70 - 80% */
PRIORITY_PLAYBACK, /* 80 - 90% */
PRIORITY_PLAYBACK, /* 90 -100% */
PRIORITY_PLAYBACK, /* 100% */
};
int new_prio = prios[pcm_fill_state];
/* Keep voice and codec threads at the same priority or else voice
* will starve if the codec thread's priority is boosted. */
if (new_prio != codec_thread_priority)
{
codec_thread_set_priority(new_prio);
voice_thread_set_priority(new_prio);
codec_thread_priority = new_prio;
}
}
#else
#define boost_codec_thread(pcm_fill_state) do{}while(0)
#endif /* HAVE_PRIORITY_SCHEDULING */
/* Get the next available buffer and size - assumes adequate space exists */
static void * get_write_buffer(size_t *size)
{
/* Obtain current chunk fill address */
size_t index = chunk_widx + pcmbuf_bytes_waiting;
size_t index_end = pcmbuf_size + PCMBUF_GUARD_SIZE;
/* Get count to the end of the buffer where a wrap will happen +
the guard */
size_t endsize = index_end - index;
/* Return available unwrapped space */
*size = MIN(*size, endsize);
return index_buffer(index);
}
/* Commit outstanding data leaving less than a chunk size remaining and
write position info to the first chunk */
static void commit_write_buffer(size_t size, unsigned long elapsed, off_t offset)
{
struct chunkdesc *desc = index_chunkdesc(chunk_widx);
stamp_chunk(desc, elapsed, offset);
/* Add this data and commit if one or more chunks are ready */
pcmbuf_bytes_waiting += size;
commit_if_needed(COMMIT_CHUNKS);
}
/* Request space in the buffer for writing output samples */
void * pcmbuf_request_buffer(int *count)
{
size_t size = *count * 4;
#ifdef HAVE_CROSSFADE
/* We're going to crossfade to a new track, which is now on its way */
if (crossfade_status == CROSSFADE_TRACK_CHANGE_STARTED)
crossfade_start();
/* If crossfade has begun, put the new track samples in crossfade_buffer */
if (crossfade_status != CROSSFADE_INACTIVE && size > CROSSFADE_BUFSIZE)
size = CROSSFADE_BUFSIZE;
else
#endif /* HAVE_CROSSFADE */
if (size > PCMBUF_MAX_BUFFER)
size = PCMBUF_MAX_BUFFER; /* constrain */
enum channel_status status = mixer_channel_status(PCM_MIXER_CHAN_PLAYBACK);
size_t remaining = pcmbuf_unplayed_bytes();
/* Need to have length bytes to prevent wrapping overwriting - leave one
descriptor free to guard so that 0 != full in ring buffer */
size_t freespace = pcmbuf_free();
if (pcmbuf_sync_position)
audio_pcmbuf_sync_position();
if (freespace < size + PCMBUF_CHUNK_SIZE)
return NULL;
/* Maintain the buffer level above the watermark */
if (status != CHANNEL_STOPPED)
{
if (low_latency_mode)
{
/* 1/4s latency. */
if (remaining > DATA_LEVEL(1))
return NULL;
}
/* Boost CPU if necessary */
size_t realrem = pcmbuf_size - freespace;
if (realrem < pcmbuf_watermark)
trigger_cpu_boost();
boost_codec_thread(realrem*10 / pcmbuf_size);
#ifdef HAVE_CROSSFADE
/* Disable crossfade if < .5s of audio */
if (remaining < DATA_LEVEL(2))
crossfade_status = CROSSFADE_INACTIVE;
#endif
}
else /* !playing */
{
/* Boost CPU for pre-buffer */
trigger_cpu_boost();
/* If pre-buffered to the watermark, start playback */
if (!pcmbuf_data_critical() && audio_pcmbuf_may_play())
pcmbuf_play_start();
}
void *buf;
#ifdef HAVE_CROSSFADE
if (crossfade_status != CROSSFADE_INACTIVE)
{
buf = crossfade_buffer; /* always CROSSFADE_BUFSIZE */
}
else
#endif
{
/* Give the maximum amount available if there's more */
if (size + PCMBUF_CHUNK_SIZE < freespace)
size = freespace - PCMBUF_CHUNK_SIZE;
buf = get_write_buffer(&size);
}
*count = size / 4;
return buf;
}
/* Handle new samples to the buffer */
void pcmbuf_write_complete(int count, unsigned long elapsed, off_t offset)
{
size_t size = count * 4;
#ifdef HAVE_CROSSFADE
if (crossfade_status != CROSSFADE_INACTIVE)
{
write_to_crossfade(size, elapsed, offset);
}
else
#endif
{
commit_write_buffer(size, elapsed, offset);
}
/* Revert to position updates by PCM */
pcmbuf_sync_position = false;
}
/** Init */
static unsigned int get_next_required_pcmbuf_chunks(void)
{
size_t size = MIN_BUFFER_SIZE;
#ifdef HAVE_CROSSFADE
if (crossfade_enable_request != CROSSFADE_ENABLE_OFF)
{
size_t seconds = global_settings.crossfade_fade_out_delay +
global_settings.crossfade_fade_out_duration;
size += seconds * BYTERATE;
}
#endif
logf("pcmbuf len: %lu", (unsigned long)(size / BYTERATE));
return size / PCMBUF_CHUNK_SIZE;
}
/* Initialize the ringbuffer state */
static void init_buffer_state(void)
{
/* Reset counters */
chunk_ridx = chunk_widx = 0;
pcmbuf_bytes_waiting = 0;
/* Reset first descriptor */
struct chunkdesc *desc = pcmbuf_descriptors;
desc->is_end = 0;
desc->pos_key = 0;
}
/* Initialize the PCM buffer. The structure looks like this:
* ...[|FADEBUF]|---------PCMBUF---------|GUARDBUF|DESCS| */
size_t pcmbuf_init(void *bufend)
{
void *bufstart;
/* Set up the buffers */
pcmbuf_desc_count = get_next_required_pcmbuf_chunks();
pcmbuf_size = pcmbuf_desc_count * PCMBUF_CHUNK_SIZE;
pcmbuf_descriptors = (struct chunkdesc *)bufend - pcmbuf_desc_count;
pcmbuf_buffer = (void *)pcmbuf_descriptors -
pcmbuf_size - PCMBUF_GUARD_SIZE;
/* Mem-align buffer chunks for more efficient handling in lower layers */
pcmbuf_buffer = ALIGN_DOWN(pcmbuf_buffer, (uintptr_t)MEM_ALIGN_SIZE);
pcmbuf_guardbuf = pcmbuf_buffer + pcmbuf_size;
bufstart = pcmbuf_buffer;
#ifdef HAVE_CROSSFADE
/* Allocate FADEBUF if it will be needed */
if (crossfade_enable_request != CROSSFADE_ENABLE_OFF)
{
bufstart -= CROSSFADE_BUFSIZE;
crossfade_buffer = bufstart;
}
pcmbuf_finish_crossfade_enable();
#endif /* HAVE_CROSSFADE */
init_buffer_state();
pcmbuf_soft_mode(false);
return bufend - bufstart;
}
/** Track change */
/* Place a track change notification in a specific descriptor or post it
immediately if the buffer is empty or the index is invalid */
static void pcmbuf_monitor_track_change_ex(size_t index, int offset)
{
if (chunk_ridx != chunk_widx && index != INVALID_BUF_INDEX)
{
/* If monitoring, set flag in specified chunk */
index_chunkdesc_offs(index, offset)->is_end = 1;
}
else
{
/* Post now if no outstanding buffers exist */
audio_pcmbuf_track_change(false);
}
}
/* Clear end of track and optionally the positioning info for all data */
static void pcmbuf_cancel_track_change(bool position)
{
size_t index = chunk_ridx;
while (1)
{
struct chunkdesc *desc = index_chunkdesc(index);
desc->is_end = 0;
if (position)
desc->pos_key = 0;
if (index == chunk_widx)
break;
index = index_next(index);
}
}
/* Place a track change notification at the end of the buffer or post it
immediately if the buffer is empty */
void pcmbuf_monitor_track_change(bool monitor)
{
pcm_play_lock();
if (monitor)
pcmbuf_monitor_track_change_ex(chunk_widx, -1);
else
pcmbuf_cancel_track_change(false);
pcm_play_unlock();
}
void pcmbuf_start_track_change(enum pcm_track_change_type type)
{
#ifdef HAVE_CROSSFADE
bool crossfade = false;
#endif
bool auto_skip = type != TRACK_CHANGE_MANUAL;
/* Commit all outstanding data before starting next track - tracks don't
comingle inside a single buffer chunk */
commit_if_needed(COMMIT_ALL_DATA);
/* Update position key so that:
1) Positions are keyed to the track to which they belong for sync
purposes
2) Buffers stamped with the outgoing track's positions are restamped
to the incoming track's positions when crossfading
*/
if (++position_key > UINT8_MAX)
position_key = 1;
if (type == TRACK_CHANGE_END_OF_DATA)
{
/* If end of all data, force playback */
if (audio_pcmbuf_may_play())
pcmbuf_play_start();
}
#ifdef HAVE_CROSSFADE
/* Determine whether this track change needs to crossfaded and how */
else if (crossfade_setting != CROSSFADE_ENABLE_OFF &&
!pcmbuf_is_crossfade_active() &&
pcmbuf_unplayed_bytes() >= DATA_LEVEL(2) &&
!low_latency_mode)
{
switch (crossfade_setting)
{
case CROSSFADE_ENABLE_AUTOSKIP:
crossfade = auto_skip;
break;
case CROSSFADE_ENABLE_MANSKIP:
crossfade = !auto_skip;
break;
case CROSSFADE_ENABLE_SHUFFLE:
crossfade = global_settings.playlist_shuffle;
break;
case CROSSFADE_ENABLE_SHUFFLE_OR_MANSKIP:
crossfade = global_settings.playlist_shuffle || !auto_skip;
break;
case CROSSFADE_ENABLE_ALWAYS:
crossfade = true;
break;
}
}
/* else crossfade is off, crossfade is already active, not enough data,
* pcm is off now (implying low data), not crossfading or low latency mode
*/
if (crossfade)
{
logf("crossfade track change");
/* Don't enable mix mode when skipping tracks manually */
crossfade_mixmode = auto_skip &&
global_settings.crossfade_fade_out_mixmode;
crossfade_auto_skip = auto_skip;
crossfade_status = CROSSFADE_TRACK_CHANGE_STARTED;
trigger_cpu_boost();
/* Cancel any pending automatic gapless transition and if a manual
skip, stop position updates */
pcm_play_lock();
pcmbuf_cancel_track_change(!auto_skip);
pcm_play_unlock();
}
else
#endif /* HAVE_CROSSFADE */
if (auto_skip)
{
/* The codec is moving on to the next track, but the current track will
* continue to play, so mark the last write chunk as the last one in
* the track */
logf("gapless track change");
#ifdef HAVE_CROSSFADE
if (crossfade_status != CROSSFADE_INACTIVE)
{
/* Crossfade is still active but crossfade is not happening - for
* now, chicken-out and clear out the buffer (just like before) to
* avoid fade pile-up on short tracks fading-in over long ones */
pcmbuf_play_stop();
}
#endif
pcmbuf_monitor_track_change(true);
}
else
{
/* Discard old data; caller needs no transition notification */
logf("manual track change");
pcmbuf_play_stop();
}
}
/** Playback */
/* PCM driver callback */
static void pcmbuf_pcm_callback(const void **start, size_t *size)
{
/*- Process the chunk that just finished -*/
size_t index = chunk_ridx;
struct chunkdesc *desc = current_desc;
if (desc)
{
/* If last chunk in the track, notify of track change */
if (desc->is_end != 0)
audio_pcmbuf_track_change(true);
/* Free it for reuse */
chunk_ridx = index = index_next(index);
}
/*- Process the new one -*/
if (index != chunk_widx && !fade_out_complete)
{
current_desc = desc = index_chunkdesc(index);
*start = index_buffer(index);
*size = desc->size;
if (desc->pos_key != 0)
{
/* Positioning chunk - notify playback */
audio_pcmbuf_position_callback(desc->elapsed, desc->offset,
desc->pos_key);
}
}
}
/* Force playback */
void pcmbuf_play_start(void)
{
logf("pcmbuf_play_start");
if (mixer_channel_status(PCM_MIXER_CHAN_PLAYBACK) == CHANNEL_STOPPED &&
chunk_widx != chunk_ridx)
{
current_desc = NULL;
mixer_channel_play_data(PCM_MIXER_CHAN_PLAYBACK, pcmbuf_pcm_callback,
NULL, 0);
}
}
/* Stop channel, empty and reset buffer */
void pcmbuf_play_stop(void)
{
logf("pcmbuf_play_stop");
/* Reset channel */
mixer_channel_stop(PCM_MIXER_CHAN_PLAYBACK);
/* Reset buffer */
init_buffer_state();
/* Revert to position updates by PCM */
pcmbuf_sync_position = false;
#ifdef HAVE_CROSSFADE
crossfade_status = CROSSFADE_INACTIVE;
#endif
/* Can unboost the codec thread here no matter who's calling,
* pretend full pcm buffer to unboost */
boost_codec_thread(10);
}
void pcmbuf_pause(bool pause)
{
logf("pcmbuf_pause: %s", pause?"pause":"play");
if (mixer_channel_status(PCM_MIXER_CHAN_PLAYBACK) != CHANNEL_STOPPED)
mixer_channel_play_pause(PCM_MIXER_CHAN_PLAYBACK, !pause);
else if (!pause)
pcmbuf_play_start();
}
/** Crossfade */
#ifdef HAVE_CROSSFADE
/* Find the buffer index that's 'size' bytes away from 'index' */
static size_t crossfade_find_index(size_t index, size_t size)
{
if (index != INVALID_BUF_INDEX)
{
size_t i = ALIGN_DOWN(index, PCMBUF_CHUNK_SIZE);
size += index - i;
while (i != chunk_widx)
{
size_t desc_size = index_chunkdesc(i)->size;
if (size < desc_size)
return i + size;
size -= desc_size;
i = index_next(i);
}
}
return INVALID_BUF_INDEX;
}
/* Align the needed buffer area up to the end of existing data */
static size_t crossfade_find_buftail(size_t buffer_rem, size_t buffer_need)
{
crossfade_index = chunk_ridx;
if (buffer_rem > buffer_need)
{
size_t distance;
if (crossfade_auto_skip)
{
/* Automatic track changes only modify the last part of the buffer,
* so find the right chunk and sample to start the crossfade */
distance = buffer_rem - buffer_need;
buffer_rem = buffer_need;
}
else
{
/* Manual skips occur immediately, but give 1/5s to process */
distance = BYTERATE / 5;
buffer_rem -= BYTERATE / 5;
}
crossfade_index = crossfade_find_index(crossfade_index, distance);
}
return buffer_rem;
}
/* Returns the number of bytes _NOT_ mixed/faded */
static size_t crossfade_mix_fade(int factor, size_t size, void *buf,
size_t *out_index, unsigned long elapsed,
off_t offset)
{
if (size == 0)
return 0;
size_t index = *out_index;
if (index == INVALID_BUF_INDEX)
return size;
const int16_t *input_buf = buf;
int16_t *output_buf = index_buffer(index);
while (size)
{
struct chunkdesc *desc = index_chunkdesc(index);
switch (offset)
{
case MIXFADE_NULLIFY_POS:
/* Stop position updates for the chunk */
desc->pos_key = 0;
break;
case MIXFADE_KEEP_POS:
/* Keep position info as it is */
break;
default:
/* Replace position info */
stamp_chunk(desc, elapsed, offset);
}
size_t rem = desc->size - (index % PCMBUF_CHUNK_SIZE);
int16_t *chunk_end = SKIPBYTES(output_buf, rem);
if (size < rem)
rem = size;
size -= rem;
do
{
/* fade left and right channel at once to keep buffer alignment */
int32_t left = output_buf[0];
int32_t right = output_buf[1];
if (input_buf)
{
/* fade the input buffer and mix into the chunk */
left += *input_buf++ * factor >> 8;
right += *input_buf++ * factor >> 8;
left = clip_sample_16(left);
right = clip_sample_16(right);
}
else
{
/* fade the chunk only */
left = left * factor >> 8;
right = right * factor >> 8;
}
*output_buf++ = left;
*output_buf++ = right;
rem -= 4;
}
while (rem);
/* move to next chunk as needed */
if (output_buf >= chunk_end)
{
index = index_next(index);
if (index == chunk_widx)
{
/* End of existing data */
*out_index = INVALID_BUF_INDEX;
return size;
}
output_buf = index_buffer(index);
}
}
*out_index = buffer_index(output_buf);
return 0;
}
/* Initializes crossfader, calculates all necessary parameters and performs
* fade-out with the PCM buffer. */
static void crossfade_start(void)
{
logf("crossfade_start");
pcm_play_lock();
/* Initialize the crossfade buffer size to all of the buffered data that
* has not yet been sent to the DMA */
size_t unplayed = pcmbuf_unplayed_bytes();
/* Reject crossfade if less than .5s of data */
if (unplayed < DATA_LEVEL(2))
{
logf("crossfade rejected");
crossfade_status = CROSSFADE_INACTIVE;
if (crossfade_auto_skip)
pcmbuf_monitor_track_change(true);
pcm_play_unlock();
return;
}
/* Fading will happen */
crossfade_status = CROSSFADE_ACTIVE;
/* Get fade info from settings. */
size_t fade_out_delay = global_settings.crossfade_fade_out_delay * BYTERATE;
size_t fade_out_rem = global_settings.crossfade_fade_out_duration * BYTERATE;
size_t fade_in_delay = global_settings.crossfade_fade_in_delay * BYTERATE;
size_t fade_in_duration = global_settings.crossfade_fade_in_duration * BYTERATE;
if (!crossfade_auto_skip)
{
/* Forego fade-in delay on manual skip - do the best to preserve auto skip
relationship */
if (fade_out_delay > fade_in_delay)
fade_out_delay -= fade_in_delay;
else
fade_out_delay = 0;
fade_in_delay = 0;
}
size_t fade_out_need = fade_out_delay + fade_out_rem;
if (!crossfade_mixmode)
{
size_t buffer_rem = crossfade_find_buftail(unplayed, fade_out_need);
pcm_play_unlock();
if (buffer_rem < fade_out_need)
{
/* Existing buffers are short */
size_t fade_out_short = fade_out_need - buffer_rem;
if (fade_out_rem >= fade_out_short)
{
/* Truncate fade-out duration */
fade_out_rem -= fade_out_short;
}
else
{
/* Truncate fade-out and fade-out delay */
fade_out_delay = fade_out_rem;
fade_out_rem = 0;
}
}
/* Completely process the crossfade fade-out effect with current PCM buffer */
/* Fade out the specified amount of the already processed audio */
size_t fade_out_total = fade_out_rem;
/* Find the right chunk and sample to start fading out */
size_t fade_out_index = crossfade_find_index(crossfade_index, fade_out_delay);
while (fade_out_rem > 0)
{
/* Each 1/20 second of audio will have the same fade applied */
size_t block_rem = MIN(BYTERATE / 20, fade_out_rem);
int factor = (fade_out_rem << 8) / fade_out_total;
fade_out_rem -= block_rem;
crossfade_mix_fade(factor, block_rem, NULL, &fade_out_index,
0, MIXFADE_KEEP_POS);
}
/* zero out the rest of the buffer */
crossfade_mix_fade(0, pcmbuf_size, NULL, &fade_out_index,
0, MIXFADE_NULLIFY_POS);
pcm_play_lock();
}
/* Initialize fade-in counters */
crossfade_fade_in_total = fade_in_duration;
crossfade_fade_in_rem = fade_in_duration;
/* Find the right chunk and sample to start fading in - redo from read
chunk in case original position were/was overrun in callback - the
track change event _must not_ ever fail to happen */
unplayed = pcmbuf_unplayed_bytes() + fade_in_delay;
crossfade_find_buftail(unplayed, fade_out_need);
if (crossfade_auto_skip)
pcmbuf_monitor_track_change_ex(crossfade_index, 0);
pcm_play_unlock();
logf("crossfade_start done!");
}
/* Perform fade-in of new track */
static void write_to_crossfade(size_t size, unsigned long elapsed, off_t offset)
{
void *buf = crossfade_buffer;
if (crossfade_fade_in_rem)
{
/* Fade factor for this packet */
int factor =
((crossfade_fade_in_total - crossfade_fade_in_rem) << 8) /
crossfade_fade_in_total;
/* Bytes to fade */
size_t fade_rem = MIN(size, crossfade_fade_in_rem);
/* We _will_ fade this many bytes */
crossfade_fade_in_rem -= fade_rem;
if (crossfade_index != INVALID_BUF_INDEX)
{
/* Mix the data */
size_t fade_total = fade_rem;
fade_rem = crossfade_mix_fade(factor, fade_rem, buf, &crossfade_index,
elapsed, offset);
fade_total -= fade_rem;
size -= fade_total;
buf += fade_total;
if (!size)
return;
}
/* Fade remaining samples in place */
int samples = fade_rem / 4;
int16_t *input_buf = buf;
while (samples--)
{
int32_t left = input_buf[0];
int32_t right = input_buf[1];
*input_buf++ = left * factor >> 8;
*input_buf++ = right * factor >> 8;
}
}
if (crossfade_index != INVALID_BUF_INDEX)
{
/* Mix the data */
size_t mix_total = size;
/* A factor of 256 means mix only, no fading */
size = crossfade_mix_fade(256, size, buf, &crossfade_index,
elapsed, offset);
buf += mix_total - size;
if (!size)
return;
}
/* Data might remain in the fade buffer yet the fade-in has run its
course - finish it off as normal chunks */
while (size > 0)
{
size_t copy_n = size;
void *outbuf = get_write_buffer(&copy_n);
memcpy(outbuf, buf, copy_n);
commit_write_buffer(copy_n, elapsed, offset);
buf += copy_n;
size -= copy_n;
}
/* if no more fading-in to do, stop the crossfade */
#if 0
/* This way (the previous way) can cause a sudden volume jump if mixable
data is used up before the fade-in completes and that just sounds wrong
-- jethead71 */
if (!crossfade_fade_in_rem || crossfade_index == INVALID_BUF_INDEX)
#endif
/* Let fade-in complete even if not fully overlapping the existing data */
if (!crossfade_fade_in_rem)
crossfade_status = CROSSFADE_INACTIVE;
}
static void pcmbuf_finish_crossfade_enable(void)
{
/* Copy the pending setting over now */
crossfade_setting = crossfade_enable_request;
pcmbuf_watermark = (crossfade_setting != CROSSFADE_ENABLE_OFF && pcmbuf_size) ?
/* If crossfading, try to keep the buffer full other than 1 second */
(pcmbuf_size - BYTERATE) :
/* Otherwise, just use the default */
PCMBUF_WATERMARK;
}
bool pcmbuf_is_crossfade_active(void)
{
return crossfade_status != CROSSFADE_INACTIVE;
}
void pcmbuf_request_crossfade_enable(int setting)
{
/* Next setting to be used, not applied now */
crossfade_enable_request = setting;
}
bool pcmbuf_is_same_size(void)
{
/* if pcmbuf_buffer is NULL, then not set up yet even once so always */
bool same_size = pcmbuf_buffer ?
(get_next_required_pcmbuf_chunks() == pcmbuf_desc_count) : true;
/* no buffer change needed, so finish crossfade setup now */
if (same_size)
pcmbuf_finish_crossfade_enable();
return same_size;
}
#endif /* HAVE_CROSSFADE */
/** Debug menu, other metrics */
/* Amount of bytes left in the buffer, accounting for uncommitted bytes */
size_t pcmbuf_free(void)
{
return pcmbuf_size - pcmbuf_unplayed_bytes() - pcmbuf_bytes_waiting;
}
/* Data bytes allocated for buffer */
size_t pcmbuf_get_bufsize(void)
{
return pcmbuf_size;
}
/* Number of committed descriptors */
int pcmbuf_used_descs(void)
{
return pcmbuf_unplayed_bytes() / PCMBUF_CHUNK_SIZE;
}
/* Total number of descriptors allocated */
int pcmbuf_descs(void)
{
return pcmbuf_desc_count;
}
/** Fading and channel volume control */
/* Sync the channel amplitude to all states */
static void pcmbuf_update_volume(void)
{
unsigned int vol = fade_vol;
if (soft_mode)
vol >>= 2;
mixer_channel_set_amplitude(PCM_MIXER_CHAN_PLAYBACK, vol);
}
/* Tick that does the fade for the playback channel */
static void pcmbuf_fade_tick(void)
{
/* ~1/3 second for full range fade */
const unsigned int fade_step = MIX_AMP_UNITY / (HZ / 3);
if (fade_state == PCM_FADING_IN)
fade_vol += MIN(fade_step, MIX_AMP_UNITY - fade_vol);
else if (fade_state == PCM_FADING_OUT)
fade_vol -= MIN(fade_step, fade_vol - MIX_AMP_MUTE);
pcmbuf_update_volume();
if (fade_vol == MIX_AMP_MUTE || fade_vol == MIX_AMP_UNITY)
{
/* Fade is complete */
tick_remove_task(pcmbuf_fade_tick);
if (fade_state == PCM_FADING_OUT)
{
/* Tell PCM to stop at its earliest convenience */
fade_out_complete = true;
}
fade_state = PCM_NOT_FADING;
}
}
/* Fade channel in or out in the background */
void pcmbuf_fade(bool fade, bool in)
{
/* Must pause any active fade */
pcm_play_lock();
if (fade_state != PCM_NOT_FADING)
tick_remove_task(pcmbuf_fade_tick);
fade_out_complete = false;
pcm_play_unlock();
if (!fade)
{
/* Simply set the level */
fade_state = PCM_NOT_FADING;
fade_vol = in ? MIX_AMP_UNITY : MIX_AMP_MUTE;
pcmbuf_update_volume();
}
else
{
/* Set direction and resume fade from current point */
fade_state = in ? PCM_FADING_IN : PCM_FADING_OUT;
tick_add_task(pcmbuf_fade_tick);
}
}
/* Return 'true' if fade is in progress */
bool pcmbuf_fading(void)
{
return fade_state != PCM_NOT_FADING;
}
/* Quiet-down the channel if 'shhh' is true or else play at normal level */
void pcmbuf_soft_mode(bool shhh)
{
/* Have to block the tick or improper order could leave volume in soft
mode if fading reads the old value first but updates after us. */
int res = fade_state != PCM_NOT_FADING ?
tick_remove_task(pcmbuf_fade_tick) : -1;
soft_mode = shhh;
pcmbuf_update_volume();
if (res == 0)
tick_add_task(pcmbuf_fade_tick);
}
/** Time and position */
/* Return the current position key value */
unsigned int pcmbuf_get_position_key(void)
{
return position_key;
}
/* Set position updates to be synchronous and immediate in addition to during
PCM frames - cancelled upon first codec insert or upon stopping */
void pcmbuf_sync_position_update(void)
{
pcmbuf_sync_position = true;
}
/** Misc */
bool pcmbuf_is_lowdata(void)
{
enum channel_status status = mixer_channel_status(PCM_MIXER_CHAN_PLAYBACK);
if (status != CHANNEL_PLAYING || pcmbuf_is_crossfade_active())
return false;
return pcmbuf_data_critical();
}
void pcmbuf_set_low_latency(bool state)
{
low_latency_mode = state;
}
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