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Playback: Fix problems with crossfade on short tracks.

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Addresses issues brought up in this thread:
http://forums.rockbox.org/index.php/topic,51605.0.html

While we're at it, improve the quality with a sample-level fader.

Change-Id: I73dde60d6858a1c9042812e26d490739e3906a1e
This commit is contained in:
Michael Sevakis 2016-12-28 00:06:39 -05:00
parent dbee727664
commit 6c837394ca
2 changed files with 363 additions and 294 deletions
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604
apps/pcmbuf.c
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@ -41,6 +41,9 @@
#include "audio.h" #include "audio.h"
#include "voice_thread.h" #include "voice_thread.h"
/* 2 channels * 2 bytes/sample, interleaved */
#define PCMBUF_SAMPLE_SIZE (2 * 2)
/* This is the target fill size of chunks on the pcm buffer /* 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 Can be any number of samples but power of two sizes make for faster and
smaller math - must be < 65536 bytes */ smaller math - must be < 65536 bytes */
@ -67,9 +70,8 @@
/* Return data level in 1/4-second increments */ /* Return data level in 1/4-second increments */
#define DATA_LEVEL(quarter_secs) (pcmbuf_sampr * (quarter_secs)) #define DATA_LEVEL(quarter_secs) (pcmbuf_sampr * (quarter_secs))
/* Number of bytes played per second: /* Number of bytes played per second */
(sample rate * 2 channels * 2 bytes/sample) */ #define BYTERATE (pcmbuf_sampr * PCMBUF_SAMPLE_SIZE)
#define BYTERATE (pcmbuf_sampr * 2 * 2)
#if MEMORYSIZE > 2 #if MEMORYSIZE > 2
/* Keep watermark high for large memory target - at least (2s) */ /* Keep watermark high for large memory target - at least (2s) */
@ -88,12 +90,15 @@
struct chunkdesc struct chunkdesc
{ {
uint16_t size; /* Actual size (0 < size <= PCMBUF_CHUNK_SIZE) */ uint16_t size; /* Actual size (0 < size <= PCMBUF_CHUNK_SIZE) */
uint8_t is_end; /* Flag indicating end of track */ uint16_t pos_key; /* Who put the position info in
uint8_t pos_key; /* Who put the position info in (0 = undefined) */ (undefined: 0, valid: 1..POSITION_KEY_MAX) */
unsigned long elapsed; /* Elapsed time to use */ unsigned long elapsed; /* Elapsed time to use */
off_t offset; /* Offset to use */ off_t offset; /* Offset to use */
}; };
#define POSITION_KEY_MAX UINT16_MAX
/* General PCM buffer data */ /* General PCM buffer data */
#define INVALID_BUF_INDEX ((size_t)0 - (size_t)1) #define INVALID_BUF_INDEX ((size_t)0 - (size_t)1)
@ -110,6 +115,7 @@ static size_t chunk_widx;
static size_t pcmbuf_bytes_waiting; static size_t pcmbuf_bytes_waiting;
static struct chunkdesc *current_desc; static struct chunkdesc *current_desc;
static size_t chunk_transidx;
static size_t pcmbuf_watermark = 0; static size_t pcmbuf_watermark = 0;
@ -131,28 +137,36 @@ static bool fade_out_complete = false;
static bool soft_mode = false; static bool soft_mode = false;
#ifdef HAVE_CROSSFADE #ifdef HAVE_CROSSFADE
/* Crossfade buffer */
static void *crossfade_buffer;
/* Crossfade related state */ /* Crossfade related state */
static int crossfade_setting; static int crossfade_setting;
static int crossfade_enable_request; static int crossfade_enable_request;
static bool crossfade_mixmode;
static bool crossfade_auto_skip;
static enum static enum
{ {
CROSSFADE_INACTIVE = 0, CROSSFADE_INACTIVE = 0, /* Crossfade is OFF */
CROSSFADE_TRACK_CHANGE_STARTED, CROSSFADE_ACTIVE, /* Crossfade is fading in */
CROSSFADE_ACTIVE, CROSSFADE_START, /* New crossfade is starting */
CROSSFADE_CONTINUE, /* Next track continues fade */
} crossfade_status = CROSSFADE_INACTIVE; } crossfade_status = CROSSFADE_INACTIVE;
/* Track the current location for processing crossfade */ static bool crossfade_mixmode;
static size_t crossfade_index; static bool crossfade_auto_skip;
static size_t crossfade_widx;
static size_t crossfade_bufidx;
/* Counters for fading in new data */ struct mixfader
static size_t crossfade_fade_in_total; {
static size_t crossfade_fade_in_rem; int32_t factor; /* Current volume factor to use */
int32_t endfac; /* Saturating end factor */
int32_t nsamp2; /* Twice the number of samples */
int32_t dfact2; /* Twice the range of factors */
int32_t ferr; /* Current error accumulator */
int32_t dfquo; /* Quotient of fade range / sample range */
int32_t dfrem; /* Remainder of fade range / sample range */
int32_t dfinc; /* Base increment (-1 or +1) */
bool alloc; /* Allocate blocks if needed else abort at EOB */
} crossfade_infader;
/* Defines for operations on position info when mixing/fading - /* Defines for operations on position info when mixing/fading -
passed in offset parameter */ passed in offset parameter */
@ -163,10 +177,16 @@ enum
/* Positive values cause stamping/restamping */ /* Positive values cause stamping/restamping */
}; };
#define MIXFADE_UNITY_BITS 16
#define MIXFADE_UNITY (1 << MIXFADE_UNITY_BITS)
static void crossfade_cancel(void);
static void crossfade_start(void); static void crossfade_start(void);
static void write_to_crossfade(size_t size, unsigned long elapsed, static void write_to_crossfade(size_t size, unsigned long elapsed,
off_t offset); off_t offset);
static void pcmbuf_finish_crossfade_enable(void); static void pcmbuf_finish_crossfade_enable(void);
#else
#define crossfade_cancel() do {} while(0)
#endif /* HAVE_CROSSFADE */ #endif /* HAVE_CROSSFADE */
/* Thread */ /* Thread */
@ -232,9 +252,9 @@ static struct chunkdesc * index_chunkdesc(size_t index)
return &pcmbuf_descriptors[index / PCMBUF_CHUNK_SIZE]; return &pcmbuf_descriptors[index / PCMBUF_CHUNK_SIZE];
} }
/* Return a chunk descriptor for a byte index in the buffer, offset by 'offset' /* Return the first byte of a chunk for a byte index in the buffer, offset by 'offset'
chunks */ chunks */
static struct chunkdesc * index_chunkdesc_offs(size_t index, int offset) static size_t index_chunk_offs(size_t index, int offset)
{ {
int i = index / PCMBUF_CHUNK_SIZE; int i = index / PCMBUF_CHUNK_SIZE;
@ -247,7 +267,53 @@ static struct chunkdesc * index_chunkdesc_offs(size_t index, int offset)
i += pcmbuf_desc_count; i += pcmbuf_desc_count;
} }
return &pcmbuf_descriptors[i]; return i * PCMBUF_CHUNK_SIZE;
}
/* Test if a buffer index lies within the committed data region */
static bool index_committed(size_t index)
{
if (index == INVALID_BUF_INDEX)
return false;
size_t ridx = chunk_ridx;
size_t widx = chunk_widx;
if (widx < ridx)
{
widx += pcmbuf_size;
if (index < ridx)
index += pcmbuf_size;
}
return index >= ridx && index < widx;
}
/* Snip the tail of buffer at chunk of specified index plus chunk offset */
void snip_buffer_tail(size_t index, int offset)
{
/* Call with PCM lockout */
if (index == INVALID_BUF_INDEX)
return;
index = index_chunk_offs(index, offset);
if (!index_committed(index) && index != chunk_widx)
return;
chunk_widx = index;
pcmbuf_bytes_waiting = 0;
index_chunkdesc(index)->pos_key = 0;
#ifdef HAVE_CROSSFADE
/* Kill crossfade if it would now be operating in the void */
if (crossfade_status != CROSSFADE_INACTIVE &&
!index_committed(crossfade_widx) && crossfade_widx != chunk_widx)
{
crossfade_cancel();
}
#endif /* HAVE_CROSSFADE */
} }
@ -280,7 +346,6 @@ static void commit_chunks(size_t threshold)
desc = index_chunkdesc(index); desc = index_chunkdesc(index);
/* Reset it before using it */ /* Reset it before using it */
desc->is_end = 0;
desc->pos_key = 0; desc->pos_key = 0;
} }
while (pcmbuf_bytes_waiting >= threshold); while (pcmbuf_bytes_waiting >= threshold);
@ -363,37 +428,32 @@ static void * get_write_buffer(size_t *size)
return index_buffer(index); return index_buffer(index);
} }
/* Commit outstanding data leaving less than a chunk size remaining and /* Commit outstanding data leaving less than a chunk size remaining */
write position info to the first chunk */ static void commit_write_buffer(size_t size)
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 */ /* Add this data and commit if one or more chunks are ready */
pcmbuf_bytes_waiting += size; pcmbuf_bytes_waiting += size;
commit_if_needed(COMMIT_CHUNKS); commit_if_needed(COMMIT_CHUNKS);
} }
/* Request space in the buffer for writing output samples */ /* Request space in the buffer for writing output samples */
void * pcmbuf_request_buffer(int *count) void * pcmbuf_request_buffer(int *count)
{ {
size_t size = *count * 4; size_t size = *count * PCMBUF_SAMPLE_SIZE;
#ifdef HAVE_CROSSFADE #ifdef HAVE_CROSSFADE
/* We're going to crossfade to a new track, which is now on its way */ /* We're going to crossfade to a new track, which is now on its way */
if (crossfade_status == CROSSFADE_TRACK_CHANGE_STARTED) if (crossfade_status > CROSSFADE_ACTIVE)
crossfade_start(); crossfade_start();
/* If crossfade has begun, put the new track samples in crossfade_buffer */ /* If crossfade has begun, put the new track samples in the crossfade
buffer area */
if (crossfade_status != CROSSFADE_INACTIVE && size > CROSSFADE_BUFSIZE) if (crossfade_status != CROSSFADE_INACTIVE && size > CROSSFADE_BUFSIZE)
size = CROSSFADE_BUFSIZE; size = CROSSFADE_BUFSIZE;
else else
#endif /* HAVE_CROSSFADE */ #endif /* HAVE_CROSSFADE */
if (size > PCMBUF_MAX_BUFFER) if (size > PCMBUF_MAX_BUFFER)
size = PCMBUF_MAX_BUFFER; /* constrain */ size = PCMBUF_MAX_BUFFER; /* constrain request */
enum channel_status status = mixer_channel_status(PCM_MIXER_CHAN_PLAYBACK); enum channel_status status = mixer_channel_status(PCM_MIXER_CHAN_PLAYBACK);
size_t remaining = pcmbuf_unplayed_bytes(); size_t remaining = pcmbuf_unplayed_bytes();
@ -425,12 +485,6 @@ void * pcmbuf_request_buffer(int *count)
trigger_cpu_boost(); trigger_cpu_boost();
boost_codec_thread(realrem*10 / pcmbuf_size); 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 */ else /* !playing */
{ {
@ -447,7 +501,8 @@ void * pcmbuf_request_buffer(int *count)
#ifdef HAVE_CROSSFADE #ifdef HAVE_CROSSFADE
if (crossfade_status != CROSSFADE_INACTIVE) if (crossfade_status != CROSSFADE_INACTIVE)
{ {
buf = crossfade_buffer; /* always CROSSFADE_BUFSIZE */ crossfade_bufidx = index_chunk_offs(chunk_ridx, -1);
buf = index_buffer(crossfade_bufidx); /* always CROSSFADE_BUFSIZE */
} }
else else
#endif #endif
@ -459,14 +514,14 @@ void * pcmbuf_request_buffer(int *count)
buf = get_write_buffer(&size); buf = get_write_buffer(&size);
} }
*count = size / 4; *count = size / PCMBUF_SAMPLE_SIZE;
return buf; return buf;
} }
/* Handle new samples to the buffer */ /* Handle new samples to the buffer */
void pcmbuf_write_complete(int count, unsigned long elapsed, off_t offset) void pcmbuf_write_complete(int count, unsigned long elapsed, off_t offset)
{ {
size_t size = count * 4; size_t size = count * PCMBUF_SAMPLE_SIZE;
#ifdef HAVE_CROSSFADE #ifdef HAVE_CROSSFADE
if (crossfade_status != CROSSFADE_INACTIVE) if (crossfade_status != CROSSFADE_INACTIVE)
@ -476,7 +531,8 @@ void pcmbuf_write_complete(int count, unsigned long elapsed, off_t offset)
else else
#endif #endif
{ {
commit_write_buffer(size, elapsed, offset); stamp_chunk(index_chunkdesc(chunk_widx), elapsed, offset);
commit_write_buffer(size);
} }
/* Revert to position updates by PCM */ /* Revert to position updates by PCM */
@ -510,13 +566,15 @@ static void init_buffer_state(void)
pcmbuf_bytes_waiting = 0; pcmbuf_bytes_waiting = 0;
/* Reset first descriptor */ /* Reset first descriptor */
struct chunkdesc *desc = pcmbuf_descriptors; if (pcmbuf_descriptors)
desc->is_end = 0; pcmbuf_descriptors->pos_key = 0;
desc->pos_key = 0;
/* Clear change notification */
chunk_transidx = INVALID_BUF_INDEX;
} }
/* Initialize the PCM buffer. The structure looks like this: /* Initialize the PCM buffer. The structure looks like this:
* ...[|FADEBUF]|---------PCMBUF---------|GUARDBUF|DESCS| */ * ...|---------PCMBUF---------|GUARDBUF|DESCS| */
size_t pcmbuf_init(void *bufend) size_t pcmbuf_init(void *bufend)
{ {
void *bufstart; void *bufstart;
@ -536,13 +594,6 @@ size_t pcmbuf_init(void *bufend)
bufstart = pcmbuf_buffer; bufstart = pcmbuf_buffer;
#ifdef HAVE_CROSSFADE #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(); pcmbuf_finish_crossfade_enable();
#else #else
pcmbuf_watermark = PCMBUF_WATERMARK; pcmbuf_watermark = PCMBUF_WATERMARK;
@ -560,33 +611,43 @@ size_t pcmbuf_init(void *bufend)
/* Place a track change notification in a specific descriptor or post it /* Place a track change notification in a specific descriptor or post it
immediately if the buffer is empty or the index is invalid */ immediately if the buffer is empty or the index is invalid */
static void pcmbuf_monitor_track_change_ex(size_t index, int offset) static void pcmbuf_monitor_track_change_ex(size_t index)
{ {
/* Call with PCM lockout */
if (chunk_ridx != chunk_widx && index != INVALID_BUF_INDEX) if (chunk_ridx != chunk_widx && index != INVALID_BUF_INDEX)
{ {
/* If monitoring, set flag in specified chunk */ /* If monitoring, set flag for one previous to specified chunk */
index_chunkdesc_offs(index, offset)->is_end = 1; index = index_chunk_offs(index, -1);
}
else /* Ensure PCM playback hasn't already played this out */
if (index_committed(index))
{ {
/* Post now if no outstanding buffers exist */ chunk_transidx = index;
audio_pcmbuf_track_change(false); return;
} }
}
/* Post now if buffer is no longer coming up */
chunk_transidx = INVALID_BUF_INDEX;
audio_pcmbuf_track_change(false);
} }
/* Clear end of track and optionally the positioning info for all data */ /* Clear end of track and optionally the positioning info for all data */
static void pcmbuf_cancel_track_change(bool position) static void pcmbuf_cancel_track_change(bool position)
{ {
/* Call with PCM lockout */
snip_buffer_tail(chunk_transidx, 1);
chunk_transidx = INVALID_BUF_INDEX;
if (!position)
return;
size_t index = chunk_ridx; size_t index = chunk_ridx;
while (1) while (1)
{ {
struct chunkdesc *desc = index_chunkdesc(index); index_chunkdesc(index)->pos_key = 0;
desc->is_end = 0;
if (position)
desc->pos_key = 0;
if (index == chunk_widx) if (index == chunk_widx)
break; break;
@ -602,7 +663,7 @@ void pcmbuf_monitor_track_change(bool monitor)
pcm_play_lock(); pcm_play_lock();
if (monitor) if (monitor)
pcmbuf_monitor_track_change_ex(chunk_widx, -1); pcmbuf_monitor_track_change_ex(chunk_widx);
else else
pcmbuf_cancel_track_change(false); pcmbuf_cancel_track_change(false);
@ -627,19 +688,22 @@ void pcmbuf_start_track_change(enum pcm_track_change_type type)
2) Buffers stamped with the outgoing track's positions are restamped 2) Buffers stamped with the outgoing track's positions are restamped
to the incoming track's positions when crossfading to the incoming track's positions when crossfading
*/ */
if (++position_key > UINT8_MAX) if (++position_key > POSITION_KEY_MAX)
position_key = 1; position_key = 1;
if (type == TRACK_CHANGE_END_OF_DATA) if (type == TRACK_CHANGE_END_OF_DATA)
{ {
crossfade_cancel();
/* If end of all data, force playback */ /* If end of all data, force playback */
if (audio_pcmbuf_may_play()) if (audio_pcmbuf_may_play())
pcmbuf_play_start(); pcmbuf_play_start();
} }
#ifdef HAVE_CROSSFADE #ifdef HAVE_CROSSFADE
/* Determine whether this track change needs to crossfaded and how */ /* Determine whether this track change needs to crossfaded and how */
else if (crossfade_setting != CROSSFADE_ENABLE_OFF && else if (crossfade_setting != CROSSFADE_ENABLE_OFF)
!pcmbuf_is_crossfade_active() && {
if (crossfade_status == CROSSFADE_INACTIVE &&
pcmbuf_unplayed_bytes() >= DATA_LEVEL(2) && pcmbuf_unplayed_bytes() >= DATA_LEVEL(2) &&
!low_latency_mode) !low_latency_mode)
{ {
@ -662,9 +726,7 @@ void pcmbuf_start_track_change(enum pcm_track_change_type type)
break; 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) if (crossfade)
{ {
@ -676,15 +738,11 @@ void pcmbuf_start_track_change(enum pcm_track_change_type type)
crossfade_auto_skip = auto_skip; crossfade_auto_skip = auto_skip;
crossfade_status = CROSSFADE_TRACK_CHANGE_STARTED; crossfade_status = CROSSFADE_START;
pcmbuf_monitor_track_change(auto_skip);
trigger_cpu_boost(); 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 else
#endif /* HAVE_CROSSFADE */ #endif /* HAVE_CROSSFADE */
@ -694,15 +752,12 @@ void pcmbuf_start_track_change(enum pcm_track_change_type type)
* continue to play, so mark the last write chunk as the last one in * continue to play, so mark the last write chunk as the last one in
* the track */ * the track */
logf("gapless track change"); logf("gapless track change");
#ifdef HAVE_CROSSFADE #ifdef HAVE_CROSSFADE
if (crossfade_status != CROSSFADE_INACTIVE) if (crossfade_status == CROSSFADE_ACTIVE)
{ crossfade_status = CROSSFADE_CONTINUE;
/* 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 #endif
pcmbuf_monitor_track_change(true); pcmbuf_monitor_track_change(true);
} }
else else
@ -726,8 +781,11 @@ static void pcmbuf_pcm_callback(const void **start, size_t *size)
if (desc) if (desc)
{ {
/* If last chunk in the track, notify of track change */ /* If last chunk in the track, notify of track change */
if (desc->is_end != 0) if (index == chunk_transidx)
{
chunk_transidx = INVALID_BUF_INDEX;
audio_pcmbuf_track_change(true); audio_pcmbuf_track_change(true);
}
/* Free it for reuse */ /* Free it for reuse */
chunk_ridx = index = index_next(index); chunk_ridx = index = index_next(index);
@ -778,9 +836,8 @@ void pcmbuf_play_stop(void)
/* Revert to position updates by PCM */ /* Revert to position updates by PCM */
pcmbuf_sync_position = false; pcmbuf_sync_position = false;
#ifdef HAVE_CROSSFADE /* Fader OFF */
crossfade_status = CROSSFADE_INACTIVE; crossfade_cancel();
#endif
/* Can unboost the codec thread here no matter who's calling, /* Can unboost the codec thread here no matter who's calling,
* pretend full pcm buffer to unboost */ * pretend full pcm buffer to unboost */
@ -801,12 +858,72 @@ void pcmbuf_pause(bool pause)
/** Crossfade */ /** Crossfade */
#ifdef HAVE_CROSSFADE #ifdef HAVE_CROSSFADE
/* Initialize a fader */
static void mixfader_init(struct mixfader *faderp, int32_t start_factor,
int32_t end_factor, size_t size, bool alloc)
{
/* Linear fade */
faderp->endfac = end_factor;
faderp->nsamp2 = size / PCMBUF_SAMPLE_SIZE * 2;
faderp->alloc = alloc;
if (faderp->nsamp2 == 0)
{
/* No data; set up as if fader finished the fade */
faderp->factor = end_factor;
return;
}
int32_t dfact2 = 2*abs(end_factor - start_factor);
faderp->factor = start_factor;
faderp->ferr = dfact2 / 2;
faderp->dfquo = dfact2 / faderp->nsamp2;
faderp->dfrem = dfact2 - faderp->dfquo*faderp->nsamp2;
faderp->dfinc = end_factor < start_factor ? -1 : +1;
faderp->dfquo *= faderp->dfinc;
}
/* Query if the fader has finished its envelope */
static inline bool mixfader_finished(const struct mixfader *faderp)
{
return faderp->factor == faderp->endfac;
}
/* Step fader by one sample */
static inline void mixfader_step(struct mixfader *faderp)
{
if (mixfader_finished(faderp))
return;
faderp->factor += faderp->dfquo;
faderp->ferr += faderp->dfrem;
if (faderp->ferr >= faderp->nsamp2)
{
faderp->factor += faderp->dfinc;
faderp->ferr -= faderp->nsamp2;
}
}
static FORCE_INLINE int32_t mixfade_sample(const struct mixfader *faderp, int32_t s)
{
return (faderp->factor * s + MIXFADE_UNITY/2) >> MIXFADE_UNITY_BITS;
}
/* Cancel crossfade operation */
static void crossfade_cancel(void)
{
crossfade_status = CROSSFADE_INACTIVE;
crossfade_widx = INVALID_BUF_INDEX;
}
/* Find the buffer index that's 'size' bytes away from 'index' */ /* Find the buffer index that's 'size' bytes away from 'index' */
static size_t crossfade_find_index(size_t index, size_t size) static size_t crossfade_find_index(size_t index, size_t size)
{ {
if (index != INVALID_BUF_INDEX) if (index != INVALID_BUF_INDEX)
{ {
size_t i = ALIGN_DOWN(index, PCMBUF_CHUNK_SIZE); size_t i = index_chunk_offs(index, 0);
size += index - i; size += index - i;
while (i != chunk_widx) while (i != chunk_widx)
@ -814,26 +931,30 @@ static size_t crossfade_find_index(size_t index, size_t size)
size_t desc_size = index_chunkdesc(i)->size; size_t desc_size = index_chunkdesc(i)->size;
if (size < desc_size) if (size < desc_size)
return i + size; {
index = i + size;
break;
}
size -= desc_size; size -= desc_size;
i = index_next(i); i = index_next(i);
} }
} }
return INVALID_BUF_INDEX; return index;
} }
/* Align the needed buffer area up to the end of existing data */ /* 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) static size_t crossfade_find_buftail(bool auto_skip, size_t buffer_rem,
size_t buffer_need, size_t *buffer_rem_outp)
{ {
crossfade_index = chunk_ridx; size_t index = chunk_ridx;
if (buffer_rem > buffer_need) if (buffer_rem > buffer_need)
{ {
size_t distance; size_t distance;
if (crossfade_auto_skip) if (auto_skip)
{ {
/* Automatic track changes only modify the last part of the buffer, /* Automatic track changes only modify the last part of the buffer,
* so find the right chunk and sample to start the crossfade */ * so find the right chunk and sample to start the crossfade */
@ -843,35 +964,41 @@ static size_t crossfade_find_buftail(size_t buffer_rem, size_t buffer_need)
else else
{ {
/* Manual skips occur immediately, but give 1/5s to process */ /* Manual skips occur immediately, but give 1/5s to process */
distance = BYTERATE / 5; distance = MIN(BYTERATE / 5, buffer_rem);
buffer_rem -= BYTERATE / 5; buffer_rem -= distance;
} }
crossfade_index = crossfade_find_index(crossfade_index, distance); index = crossfade_find_index(index, distance);
} }
return buffer_rem; if (buffer_rem_outp)
*buffer_rem_outp = buffer_rem;
return index;
} }
/* Returns the number of bytes _NOT_ mixed/faded */ /* Run a fader on some buffers */
static size_t crossfade_mix_fade(int factor, size_t size, void *buf, static void crossfade_mix_fade(struct mixfader *faderp, size_t size,
size_t *out_index, unsigned long elapsed, void *input_buf, size_t *out_index,
off_t offset) unsigned long elapsed, off_t offset)
{ {
if (size == 0) if (size == 0)
return 0; return;
size_t index = *out_index; size_t index = *out_index;
if (index == INVALID_BUF_INDEX) if (index == INVALID_BUF_INDEX)
return size; return;
const int16_t *input_buf = buf; int16_t *inbuf = input_buf;
int16_t *output_buf = index_buffer(index);
bool alloced = inbuf && faderp->alloc &&
index_chunk_offs(index, 0) == chunk_widx;
while (size) while (size)
{ {
struct chunkdesc *desc = index_chunkdesc(index); struct chunkdesc *desc = index_chunkdesc(index);
int16_t *outbuf = index_buffer(index);
switch (offset) switch (offset)
{ {
@ -887,60 +1014,77 @@ static size_t crossfade_mix_fade(int factor, size_t size, void *buf,
stamp_chunk(desc, elapsed, offset); stamp_chunk(desc, elapsed, offset);
} }
size_t rem = desc->size - (index % PCMBUF_CHUNK_SIZE); size_t amount = (alloced ? PCMBUF_CHUNK_SIZE : desc->size)
int16_t *chunk_end = SKIPBYTES(output_buf, rem); - (index % PCMBUF_CHUNK_SIZE);
int16_t *chunkend = SKIPBYTES(outbuf, amount);
if (size < rem) if (size < amount)
rem = size; amount = size;
size -= rem; size -= amount;
do if (alloced)
{ {
/* fade left and right channel at once to keep buffer alignment */ /* Fade the input buffer into the new destination chunk */
int32_t left = output_buf[0]; for (size_t s = amount; s != 0; s -= PCMBUF_SAMPLE_SIZE)
int32_t right = output_buf[1];
if (input_buf)
{ {
/* fade the input buffer and mix into the chunk */ *outbuf++ = mixfade_sample(faderp, *inbuf++);
left += *input_buf++ * factor >> 8; *outbuf++ = mixfade_sample(faderp, *inbuf++);
right += *input_buf++ * factor >> 8; mixfader_step(faderp);
left = clip_sample_16(left); }
right = clip_sample_16(right);
commit_write_buffer(amount);
}
else if (inbuf)
{
/* Fade the input buffer and mix into the destination chunk */
for (size_t s = amount; s != 0; s -= PCMBUF_SAMPLE_SIZE)
{
int32_t left = outbuf[0];
int32_t right = outbuf[1];
left += mixfade_sample(faderp, *inbuf++);
right += mixfade_sample(faderp, *inbuf++);
*outbuf++ = clip_sample_16(left);
*outbuf++ = clip_sample_16(right);
mixfader_step(faderp);
}
} }
else else
{ {
/* fade the chunk only */ /* Fade the chunk in place */
left = left * factor >> 8; for (size_t s = amount; s != 0; s -= PCMBUF_SAMPLE_SIZE)
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)
{ {
int32_t left = outbuf[0];
int32_t right = outbuf[1];
*outbuf++ = mixfade_sample(faderp, left);
*outbuf++ = mixfade_sample(faderp, right);
mixfader_step(faderp);
}
}
if (outbuf < chunkend)
{
index += amount;
continue;
}
/* Move destination to next chunk as needed */
index = index_next(index); index = index_next(index);
if (index == chunk_widx) if (index == chunk_widx)
{ {
/* End of existing data */ /* End of existing data */
*out_index = INVALID_BUF_INDEX; if (!inbuf || !faderp->alloc)
return size; {
index = INVALID_BUF_INDEX;
break;
} }
output_buf = index_buffer(index); alloced = true;
} }
} }
*out_index = buffer_index(output_buf); *out_index = index;
return 0;
} }
/* Initializes crossfader, calculates all necessary parameters and performs /* Initializes crossfader, calculates all necessary parameters and performs
@ -951,6 +1095,19 @@ static void crossfade_start(void)
pcm_play_lock(); pcm_play_lock();
if (crossfade_status == CROSSFADE_CONTINUE)
{
logf("fade-in continuing");
crossfade_status = CROSSFADE_ACTIVE;
if (crossfade_auto_skip)
pcmbuf_monitor_track_change_ex(crossfade_widx);
pcm_play_unlock();
return;
}
/* Initialize the crossfade buffer size to all of the buffered data that /* Initialize the crossfade buffer size to all of the buffered data that
* has not yet been sent to the DMA */ * has not yet been sent to the DMA */
size_t unplayed = pcmbuf_unplayed_bytes(); size_t unplayed = pcmbuf_unplayed_bytes();
@ -959,12 +1116,7 @@ static void crossfade_start(void)
if (unplayed < DATA_LEVEL(2)) if (unplayed < DATA_LEVEL(2))
{ {
logf("crossfade rejected"); logf("crossfade rejected");
crossfade_cancel();
crossfade_status = CROSSFADE_INACTIVE;
if (crossfade_auto_skip)
pcmbuf_monitor_track_change(true);
pcm_play_unlock(); pcm_play_unlock();
return; return;
} }
@ -982,11 +1134,7 @@ static void crossfade_start(void)
{ {
/* Forego fade-in delay on manual skip - do the best to preserve auto skip /* Forego fade-in delay on manual skip - do the best to preserve auto skip
relationship */ relationship */
if (fade_out_delay > fade_in_delay) fade_out_delay -= MIN(fade_out_delay, fade_in_delay);
fade_out_delay -= fade_in_delay;
else
fade_out_delay = 0;
fade_in_delay = 0; fade_in_delay = 0;
} }
@ -994,7 +1142,10 @@ static void crossfade_start(void)
if (!crossfade_mixmode) if (!crossfade_mixmode)
{ {
size_t buffer_rem = crossfade_find_buftail(unplayed, fade_out_need); /* Completely process the crossfade fade-out effect with current PCM buffer */
size_t buffer_rem;
size_t index = crossfade_find_buftail(crossfade_auto_skip, unplayed,
fade_out_need, &buffer_rem);
pcm_play_unlock(); pcm_play_unlock();
@ -1003,59 +1154,52 @@ static void crossfade_start(void)
/* Existing buffers are short */ /* Existing buffers are short */
size_t fade_out_short = fade_out_need - buffer_rem; size_t fade_out_short = fade_out_need - buffer_rem;
if (fade_out_rem >= fade_out_short) if (fade_out_delay >= fade_out_short)
{ {
/* Truncate fade-out duration */ /* Truncate fade-out delay */
fade_out_rem -= fade_out_short; fade_out_delay -= fade_out_short;
} }
else else
{ {
/* Truncate fade-out and fade-out delay */ /* Truncate fade-out and eliminate fade-out delay */
fade_out_delay = fade_out_rem; fade_out_rem = buffer_rem;
fade_out_rem = 0; fade_out_delay = 0;
}
} }
/* Completely process the crossfade fade-out effect with current PCM buffer */ fade_out_need = fade_out_delay + fade_out_rem;
}
/* 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 */ /* Find the right chunk and sample to start fading out */
size_t fade_out_index = crossfade_find_index(crossfade_index, fade_out_delay); index = crossfade_find_index(index, fade_out_delay);
while (fade_out_rem > 0) /* Fade out the specified amount of the already processed audio */
{ struct mixfader outfader;
/* 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; mixfader_init(&outfader, MIXFADE_UNITY, 0, fade_out_rem, false);
crossfade_mix_fade(&outfader, fade_out_rem, NULL, &index, 0,
MIXFADE_KEEP_POS);
crossfade_mix_fade(factor, block_rem, NULL, &fade_out_index, /* Zero-out the rest of the buffer */
0, MIXFADE_KEEP_POS); crossfade_mix_fade(&outfader, pcmbuf_size, NULL, &index, 0,
} MIXFADE_NULLIFY_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(); pcm_play_lock();
} }
/* Initialize fade-in counters */ /* Initialize fade-in counters */
crossfade_fade_in_total = fade_in_duration; mixfader_init(&crossfade_infader, 0, MIXFADE_UNITY, fade_in_duration, true);
crossfade_fade_in_rem = fade_in_duration;
/* Find the right chunk and sample to start fading in - redo from read /* Find the right chunk and sample to start fading in - redo from read
chunk in case original position were/was overrun in callback - the chunk in case original position were/was overrun in callback - the
track change event _must not_ ever fail to happen */ track change event _must not_ ever fail to happen */
unplayed = pcmbuf_unplayed_bytes() + fade_in_delay; unplayed = pcmbuf_unplayed_bytes() + fade_in_delay;
crossfade_find_buftail(unplayed, fade_out_need); crossfade_widx = crossfade_find_buftail(crossfade_auto_skip, unplayed,
fade_out_need, NULL);
/* Move track transistion to chunk before the first one of incoming track */
if (crossfade_auto_skip) if (crossfade_auto_skip)
pcmbuf_monitor_track_change_ex(crossfade_index, 0); pcmbuf_monitor_track_change_ex(crossfade_widx);
pcm_play_unlock(); pcm_play_unlock();
@ -1065,83 +1209,16 @@ static void crossfade_start(void)
/* Perform fade-in of new track */ /* Perform fade-in of new track */
static void write_to_crossfade(size_t size, unsigned long elapsed, off_t offset) 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 */ /* Mix the data */
size_t fade_total = fade_rem; crossfade_mix_fade(&crossfade_infader, size, index_buffer(crossfade_bufidx),
fade_rem = crossfade_mix_fade(factor, fade_rem, buf, &crossfade_index, &crossfade_widx, elapsed, offset);
elapsed, offset);
fade_total -= fade_rem;
size -= fade_total;
buf += fade_total;
if (!size) /* If no more fading-in to do, stop the crossfade */
return; if (mixfader_finished(&crossfade_infader) &&
} index_chunk_offs(crossfade_widx, 0) == chunk_widx)
/* Fade remaining samples in place */
int samples = fade_rem / 4;
int16_t *input_buf = buf;
while (samples--)
{ {
int32_t left = input_buf[0]; crossfade_cancel();
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) static void pcmbuf_finish_crossfade_enable(void)
@ -1156,11 +1233,6 @@ static void pcmbuf_finish_crossfade_enable(void)
PCMBUF_WATERMARK; PCMBUF_WATERMARK;
} }
bool pcmbuf_is_crossfade_active(void)
{
return crossfade_status != CROSSFADE_INACTIVE;
}
void pcmbuf_request_crossfade_enable(int setting) void pcmbuf_request_crossfade_enable(int setting)
{ {
/* Next setting to be used, not applied now */ /* Next setting to be used, not applied now */
@ -1322,7 +1394,7 @@ bool pcmbuf_is_lowdata(void)
{ {
enum channel_status status = mixer_channel_status(PCM_MIXER_CHAN_PLAYBACK); enum channel_status status = mixer_channel_status(PCM_MIXER_CHAN_PLAYBACK);
if (status != CHANNEL_PLAYING || pcmbuf_is_crossfade_active()) if (status != CHANNEL_PLAYING || crossfade_status != CROSSFADE_INACTIVE)
return false; return false;
return pcmbuf_data_critical(); return pcmbuf_data_critical();

3
apps/pcmbuf.h
View file

@ -50,13 +50,10 @@ void pcmbuf_start_track_change(enum pcm_track_change_type type);
/* Crossfade */ /* Crossfade */
#ifdef HAVE_CROSSFADE #ifdef HAVE_CROSSFADE
bool pcmbuf_is_crossfade_active(void);
void pcmbuf_request_crossfade_enable(int setting); void pcmbuf_request_crossfade_enable(int setting);
bool pcmbuf_is_same_size(void); bool pcmbuf_is_same_size(void);
#else #else
/* Dummy functions with sensible returns */ /* 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) static FORCE_INLINE void pcmbuf_request_crossfade_enable(bool on_off)
{ return; (void)on_off; } { return; (void)on_off; }
static FORCE_INLINE bool pcmbuf_is_same_size(void) static FORCE_INLINE bool pcmbuf_is_same_size(void)