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rockbox/apps/pcmbuf.c
Brandon Low 9535a9a639 Fix some of the voice and beep bugs that people have noticed since my new pcmbuf code went in, reduce code duplication, and improve performance while I'm at it 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@8775 a1c6a512-1295-4272-9138-f99709370657
2006-02-22 01:56:44 +00:00

941 lines
26 KiB
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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2005 by Miika Pekkarinen
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <stdbool.h>
#include <stdio.h>
#include "config.h"
#include "debug.h"
#include "panic.h"
#include <kernel.h>
#include "pcmbuf.h"
#include "pcm_playback.h"
#include "logf.h"
#ifndef SIMULATOR
#include "cpu.h"
#endif
#include "system.h"
#include <string.h>
#include "buffer.h"
#include "settings.h"
#include "audio.h"
#include "dsp.h"
#define PCMBUF_WATERMARK (NATIVE_FREQUENCY * 4 * 1)
/* Size of the PCM buffer. */
static size_t pcmbuf_size IDATA_ATTR = 0;
static char *audiobuffer IDATA_ATTR;
/* Current audio buffer write index. */
static size_t audiobuffer_pos IDATA_ATTR;
/* Amount of bytes left in the buffer. */
size_t audiobuffer_free IDATA_ATTR;
/* Amount audiobuffer_pos will be increased.*/
static size_t audiobuffer_fillpos IDATA_ATTR;
static char *guardbuf IDATA_ATTR;
static void (*pcmbuf_event_handler)(void) IDATA_ATTR;
static void (*position_callback)(size_t size) IDATA_ATTR;
/* Crossfade related. */
static int crossfade_mode IDATA_ATTR;
static bool crossfade_enabled IDATA_ATTR;
static bool crossfade_active IDATA_ATTR;
static bool crossfade_init IDATA_ATTR;
static size_t crossfade_pos IDATA_ATTR;
static size_t crossfade_rem IDATA_ATTR;
static struct mutex pcmbuf_mutex IDATA_ATTR;
/* Crossfade modes. If CFM_CROSSFADE is selected, normal
* crossfader will activate. Selecting CFM_FLUSH is a special
* operation that only overwrites the pcm buffer without crossfading.
*/
enum {
CFM_CROSSFADE,
CFM_MIX,
CFM_FLUSH
};
static size_t crossfade_fade_in_amount IDATA_ATTR;
static size_t crossfade_fade_in_rem IDATA_ATTR;
/* Structure we can use to queue pcm chunks in memory to be played
* by the driver code. */
struct pcmbufdesc
{
void *addr;
size_t size;
struct pcmbufdesc* link;
/* Call this when the buffer has been played */
void (*callback)(void);
};
static size_t pcmbuf_descsize;
static struct pcmbufdesc *pcmbuf_read IDATA_ATTR;
static struct pcmbufdesc *pcmbuf_read_end IDATA_ATTR;
static struct pcmbufdesc *pcmbuf_write IDATA_ATTR;
static struct pcmbufdesc *pcmbuf_write_end IDATA_ATTR;
static size_t last_chunksize IDATA_ATTR;
static size_t pcmbuf_unplayed_bytes IDATA_ATTR;
static size_t pcmbuf_mix_used_bytes IDATA_ATTR;
static size_t pcmbuf_watermark IDATA_ATTR;
static short *mixpos IDATA_ATTR;
static bool low_latency_mode = false;
/* Helpful macros for use in conditionals this assumes some of the above
* static variable names */
#define NEED_FLUSH(position) \
(audiobuffer_fillpos > PCMBUF_TARGET_CHUNK || position >= pcmbuf_size)
#define LOW_DATA(quarter_secs) \
(pcmbuf_unplayed_bytes < NATIVE_FREQUENCY * quarter_secs)
static void pcmbuf_flush_audio(void);
static void pcmbuf_under_watermark(void);
#if defined(HAVE_ADJUSTABLE_CPU_FREQ) && !defined(SIMULATOR)
static bool boost_mode;
void pcmbuf_boost(bool state)
{
static bool boost_state = false;
if (crossfade_init || crossfade_active || boost_mode)
return;
if (state != boost_state) {
cpu_boost(state);
boost_state = state;
}
}
void pcmbuf_set_boost_mode(bool state)
{
if (state)
pcmbuf_boost(true);
boost_mode = state;
}
#endif
#define CALL_IF_EXISTS(function, args...) if (function) function(args)
/* This function has 2 major logical parts (separated by brackets both for
* readability and variable scoping). The first part performs the
* operastions related to finishing off the last buffer we fed to the DMA.
* The second part performs the operations involved in sending a new buffer
* to the DMA. Finally the function checks the status of the buffer and
* boosts if necessary */
static void pcmbuf_callback(unsigned char** start, size_t* size) ICODE_ATTR;
static void pcmbuf_callback(unsigned char** start, size_t* size)
{
{
struct pcmbufdesc *pcmbuf_current = pcmbuf_read;
/* Take the finished buffer out of circulation */
pcmbuf_read = pcmbuf_current->link;
{
size_t finished_size = last_chunksize;
audiobuffer_free += finished_size;
/* The buffer is finished, call the callback functions */
CALL_IF_EXISTS(position_callback, finished_size);
}
CALL_IF_EXISTS(pcmbuf_current->callback);
/* Put the finished buffer back into circulation */
pcmbuf_write_end->link = pcmbuf_current;
pcmbuf_write_end = pcmbuf_current;
}
{
/* Send the new buffer to the pcm */
struct pcmbufdesc *pcmbuf_new = pcmbuf_read;
size_t *realsize = size;
unsigned char** realstart = start;
if(pcmbuf_new)
{
size_t current_size = pcmbuf_new->size;
pcmbuf_unplayed_bytes -= current_size;
*realsize = current_size;
last_chunksize = current_size;
*realstart = pcmbuf_new->addr;
}
else
{
/* No more buffers */
last_chunksize = 0;
*realsize = 0;
*realstart = NULL;
CALL_IF_EXISTS(pcmbuf_event_handler);
}
}
}
void pcmbuf_set_position_callback(void (*callback)(size_t size))
{
position_callback = callback;
}
static void pcmbuf_set_watermark_bytes(size_t numbytes)
{
pcmbuf_watermark = numbytes;
}
/* This is really just part of pcmbuf_flush_fillpos, but is easier to keep
* in a separate function for the moment */
static inline void pcmbuf_add_chunk(void)
{
register size_t size = audiobuffer_fillpos;
/* Grab the next description to write, and change the write pointer */
register struct pcmbufdesc *pcmbuf_current = pcmbuf_write;
pcmbuf_write = pcmbuf_current->link;
/* Fill in the values in the new buffer chunk */
pcmbuf_current->addr = &audiobuffer[audiobuffer_pos];
pcmbuf_current->size = size;
pcmbuf_current->callback = pcmbuf_event_handler;
pcmbuf_current->link = NULL;
/* This is single use only */
pcmbuf_event_handler = NULL;
if (pcmbuf_read) {
/* If there is already a read buffer setup, add to it */
pcmbuf_read_end->link = pcmbuf_current;
} else {
/* Otherwise create the buffer */
pcmbuf_read = pcmbuf_current;
}
/* This is now the last buffer to read */
pcmbuf_read_end = pcmbuf_current;
/* Update bytes counters */
pcmbuf_unplayed_bytes += size;
if (pcmbuf_mix_used_bytes > size)
pcmbuf_mix_used_bytes -= size;
else
pcmbuf_mix_used_bytes = 0;
audiobuffer_pos += size;
if (audiobuffer_pos >= pcmbuf_size)
audiobuffer_pos = 0;
audiobuffer_fillpos = 0;
}
static void pcmbuf_under_watermark(void)
{
/* Fill audio buffer by boosting cpu */
pcmbuf_boost(true);
/* Disable crossfade if < .5s of audio */
if (LOW_DATA(2) && crossfade_mode != CFM_FLUSH)
crossfade_active = false;
}
void pcmbuf_set_event_handler(void (*event_handler)(void))
{
pcmbuf_event_handler = event_handler;
}
unsigned int pcmbuf_get_latency(void)
{
/* Be careful how this calculation is rearranted, it's easy to overflow */
size_t bytes = pcmbuf_unplayed_bytes + pcm_get_bytes_waiting();
return bytes / 4 / (NATIVE_FREQUENCY/1000);
}
void pcmbuf_set_low_latency(bool state)
{
low_latency_mode = state;
}
bool pcmbuf_is_lowdata(void)
{
if (!pcm_is_playing() || pcm_is_paused() ||
crossfade_init || crossfade_active)
return false;
/* 0.5 seconds of buffer is low data */
return LOW_DATA(2);
}
bool pcmbuf_crossfade_init(bool manual_skip)
{
if (pcmbuf_unplayed_bytes < PCMBUF_TARGET_CHUNK * 8
|| !pcmbuf_is_crossfade_enabled()
|| crossfade_active || crossfade_init || low_latency_mode) {
pcmbuf_flush_audio();
return false;
}
logf("pcmbuf_crossfade_init");
pcmbuf_boost(true);
/* Don't enable mix mode when skipping tracks manually. */
if (manual_skip)
crossfade_mode = CFM_CROSSFADE;
else
crossfade_mode = global_settings.crossfade_fade_out_mixmode
? CFM_MIX : CFM_CROSSFADE;
crossfade_init = true;
return true;
}
void pcmbuf_play_stop(void)
{
mutex_lock(&pcmbuf_mutex);
/** Prevent a very tiny pop from happening by muting audio
* until dma has been initialized. */
pcm_mute(true);
pcm_play_stop();
pcm_mute(false);
pcmbuf_unplayed_bytes = 0;
pcmbuf_mix_used_bytes = 0;
if (pcmbuf_read) {
pcmbuf_write_end->link = pcmbuf_read;
pcmbuf_write_end = pcmbuf_read_end;
pcmbuf_read = pcmbuf_read_end = NULL;
}
audiobuffer_pos = 0;
audiobuffer_fillpos = 0;
audiobuffer_free = pcmbuf_size;
crossfade_init = false;
crossfade_active = false;
pcmbuf_set_boost_mode(false);
pcmbuf_boost(false);
mutex_unlock(&pcmbuf_mutex);
}
int pcmbuf_used_descs(void) {
struct pcmbufdesc *pcmbuf_temp = pcmbuf_read;
unsigned int i = 0;
while (pcmbuf_temp) {
pcmbuf_temp = pcmbuf_temp->link;
i++;
}
return i;
}
int pcmbuf_descs(void) {
return pcmbuf_size / PCMBUF_MINAVG_CHUNK;
}
size_t get_pcmbuf_descsize(void) {
return pcmbuf_descsize;
}
static void pcmbuf_init_pcmbuffers(void) {
struct pcmbufdesc *next = pcmbuf_write;
next++;
pcmbuf_write_end = pcmbuf_write;
while ((void *)next < (void *)audiobufend) {
pcmbuf_write_end->link=next;
pcmbuf_write_end=next;
next++;
}
}
/* Initialize the pcmbuffer the structure looks like this:
* ...CODECBUFFER|---------PCMBUF---------|GUARDBUF|DESCS| */
void pcmbuf_init(size_t bufsize)
{
mutex_init(&pcmbuf_mutex);
pcmbuf_size = bufsize;
pcmbuf_descsize = pcmbuf_descs()*sizeof(struct pcmbufdesc);
audiobuffer = (char *)&audiobuf[(audiobufend - audiobuf) -
(pcmbuf_size + PCMBUF_FADE_CHUNK + pcmbuf_descsize)];
guardbuf = &audiobuffer[pcmbuf_size];
pcmbuf_write = (struct pcmbufdesc *)(&guardbuf[PCMBUF_FADE_CHUNK]);
pcmbuf_init_pcmbuffers();
position_callback = NULL;
pcmbuf_event_handler = NULL;
pcmbuf_play_stop();
}
size_t pcmbuf_get_bufsize(void)
{
return pcmbuf_size;
}
/** Initialize a track switch so that audio playback will not stop but
* the switch to next track would happen as soon as possible.
*/
static void pcmbuf_flush_audio(void)
{
if (crossfade_init || crossfade_active || !pcm_is_playing()) {
pcmbuf_play_stop();
return ;
}
pcmbuf_boost(true);
crossfade_mode = CFM_FLUSH;
crossfade_init = true;
}
void pcmbuf_pause(bool pause) {
pcm_mute(pause);
pcm_play_pause(!pause);
pcmbuf_boost(!pause);
}
/* Force playback. */
void pcmbuf_play_start(void)
{
mutex_lock(&pcmbuf_mutex);
if (!pcm_is_playing() && pcmbuf_unplayed_bytes)
{
/** Prevent a very tiny pop from happening by muting audio
* until dma has been initialized. */
pcm_mute(true);
last_chunksize = pcmbuf_read->size;
pcmbuf_unplayed_bytes -= last_chunksize;
pcm_play_data(pcmbuf_callback,
(unsigned char *)pcmbuf_read->addr, last_chunksize);
/* Now unmute the audio. */
pcm_mute(false);
}
mutex_unlock(&pcmbuf_mutex);
}
/**
* Commit samples waiting to the pcm buffer.
*/
static void pcmbuf_flush_fillpos(void)
{
mutex_lock(&pcmbuf_mutex);
if (audiobuffer_fillpos) {
/* Never use the last buffer descriptor */
while (pcmbuf_write == pcmbuf_write_end) {
logf("pcmbuf_flush_fillpos no descriptors");
/* Deboost to let the playback catchup */
pcmbuf_boost(false);
/* Let someone else have fun in the meantime */
sleep(1);
/* This is a fatal error situation that should never happen. */
if (!pcm_is_playing()) {
logf("pcmbuf_flush_fillpos error");
pcmbuf_play_start();
return ;
}
}
pcmbuf_add_chunk();
}
mutex_unlock(&pcmbuf_mutex);
}
/**
* Completely process the crossfade fade out effect with current pcm buffer.
*/
static void crossfade_process_buffer(unsigned int fade_in_delay,
unsigned int fade_out_delay, size_t fade_out_rem)
{
size_t amount;
size_t pos;
short *buf;
/* Fade out the entire current buffer according to settings. */
amount = fade_out_rem;
pos = crossfade_pos + fade_out_delay*2;
while (fade_out_rem > 0 && crossfade_mode == CFM_CROSSFADE)
{
size_t blocksize = MIN(8192, fade_out_rem);
int factor = (fade_out_rem<<8)/amount;
/* Prevent pcmbuffer from wrapping. */
if (pos >= pcmbuf_size) pos -= pcmbuf_size;
blocksize = MIN((pcmbuf_size - pos)/2, blocksize);
buf = (short *)&audiobuffer[pos];
fade_out_rem -= blocksize;
pos += blocksize * 2;
while (blocksize > 0)
{
*buf = (*buf * factor) >> 8;
*buf++;
blocksize--;
}
}
/* And finally set the mixing position where we should start fading in. */
crossfade_rem -= fade_in_delay;
crossfade_pos += fade_in_delay*2;
if (crossfade_pos >= pcmbuf_size)
crossfade_pos -= pcmbuf_size;
logf("process done!");
}
/**
* Initializes crossfader, calculates all necessary parameters and
* performs fade-out with the pcm buffer.
*/
static void crossfade_start(void)
{
size_t fade_out_rem = 0;
unsigned int fade_out_delay = 0;
unsigned fade_in_delay = 0;
crossfade_init = 0;
/* Reject crossfade if less than .5s of data */
if (LOW_DATA(2)) {
logf("crossfade rejected");
pcmbuf_play_stop();
return ;
}
logf("crossfade_start");
pcmbuf_boost(true);
pcmbuf_flush_fillpos();
crossfade_active = true;
crossfade_pos = audiobuffer_pos;
/* Initialize the crossfade buffer size to all of the buffered data that
* has not yet been sent to the DMA */
crossfade_rem = pcmbuf_unplayed_bytes / 2;
switch (crossfade_mode) {
case CFM_MIX:
case CFM_CROSSFADE:
/* Get fade out delay from settings. */
fade_out_delay = NATIVE_FREQUENCY
* global_settings.crossfade_fade_out_delay * 2;
/* Get fade out duration from settings. */
fade_out_rem = NATIVE_FREQUENCY
* global_settings.crossfade_fade_out_duration * 2;
/* We want only to modify the last part of the buffer. */
if (crossfade_rem > fade_out_rem + fade_out_delay)
crossfade_rem = fade_out_rem + fade_out_delay;
/* Truncate fade out duration if necessary. */
if (crossfade_rem < fade_out_rem + fade_out_delay)
fade_out_rem -= (fade_out_rem + fade_out_delay) - crossfade_rem;
/* Get also fade in duration and delays from settings. */
crossfade_fade_in_rem = NATIVE_FREQUENCY
* global_settings.crossfade_fade_in_duration * 2;
crossfade_fade_in_amount = crossfade_fade_in_rem;
/* We should avoid to divide by zero. */
if (crossfade_fade_in_amount == 0)
crossfade_fade_in_amount = 1;
fade_in_delay = NATIVE_FREQUENCY
* global_settings.crossfade_fade_in_delay * 2;
/* Decrease the fade out delay if necessary. */
if (crossfade_rem < fade_out_rem + fade_out_delay)
fade_out_delay -=
(fade_out_rem + fade_out_delay) - crossfade_rem;
break ;
case CFM_FLUSH:
crossfade_fade_in_rem = 0;
crossfade_fade_in_amount = 0;
break ;
}
if (crossfade_pos < crossfade_rem * 2)
crossfade_pos += pcmbuf_size;
crossfade_pos -= crossfade_rem*2;
if (crossfade_mode != CFM_FLUSH) {
/* Process the fade out part of the crossfade. */
crossfade_process_buffer(fade_in_delay, fade_out_delay, fade_out_rem);
}
}
/**
* Fades in samples passed to the function and inserts them
* to the pcm buffer.
*/
static void fade_insert(const short *inbuf, size_t length)
{
size_t copy_n;
int factor;
unsigned int i, samples;
short *buf;
factor = ((crossfade_fade_in_amount-crossfade_fade_in_rem)<<8)
/crossfade_fade_in_amount;
while (audiobuffer_free < length)
{
pcmbuf_boost(false);
sleep(1);
}
audiobuffer_free -= length;
while (length > 0) {
unsigned int audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
/* Flush as needed */
if (NEED_FLUSH(audiobuffer_index))
{
pcmbuf_flush_fillpos();
audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
}
copy_n = MIN(length, pcmbuf_size - audiobuffer_index);
buf = (short *)&audiobuffer[audiobuffer_index];
samples = copy_n / 2;
for (i = 0; i < samples; i++)
buf[i] = (inbuf[i] * factor) >> 8;
inbuf += samples;
audiobuffer_fillpos += copy_n;
length -= copy_n;
}
}
/**
* Fades in buf2 and mixes it with buf.
*/
static int crossfade(short *buf, const short *buf2, unsigned int length)
{
size_t size;
unsigned int i;
size_t size_insert = 0;
int factor;
size = MIN(length, crossfade_rem);
switch (crossfade_mode) {
/* Fade in the current stream and mix it. */
case CFM_MIX:
case CFM_CROSSFADE:
factor = ((crossfade_fade_in_amount-crossfade_fade_in_rem)<<8) /
crossfade_fade_in_amount;
for (i = 0; i < size; i++) {
buf[i] = MIN(32767, MAX(-32768,
buf[i] + ((buf2[i] * factor) >> 8)));
}
break ;
/* Join two streams. */
case CFM_FLUSH:
for (i = 0; i < size; i++) {
buf[i] = buf2[i];
}
//memcpy((char *)buf, (char *)buf2, size*2);
break ;
}
if (crossfade_fade_in_rem > size)
crossfade_fade_in_rem = crossfade_fade_in_rem - size;
else
crossfade_fade_in_rem = 0;
crossfade_rem -= size;
if (crossfade_rem == 0)
{
if (crossfade_fade_in_rem > 0 && crossfade_fade_in_amount > 0)
{
size_insert = MIN(crossfade_fade_in_rem, length - size);
fade_insert(&buf2[size], size_insert*2);
crossfade_fade_in_rem -= size_insert;
}
if (crossfade_fade_in_rem == 0)
crossfade_active = false;
}
return size + size_insert;
}
static void pcmbuf_flush_buffer(const char *buf, size_t length)
{
size_t copy_n;
audiobuffer_free -= length;
while (length > 0) {
size_t audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
if (NEED_FLUSH(audiobuffer_index))
{
pcmbuf_flush_fillpos();
audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
}
copy_n = MIN(length, pcmbuf_size - audiobuffer_index);
memcpy(&audiobuffer[audiobuffer_index], buf, copy_n);
buf += copy_n;
audiobuffer_fillpos += copy_n;
length -= copy_n;
}
}
static void flush_crossfade(const char *buf, size_t length) {
size_t copy_n;
while (length > 0 && crossfade_active) {
copy_n = MIN(length, pcmbuf_size - crossfade_pos);
copy_n = 2 * crossfade((short *)&audiobuffer[crossfade_pos],
(const short *)buf, copy_n/2);
buf += copy_n;
length -= copy_n;
crossfade_pos += copy_n;
if (crossfade_pos >= pcmbuf_size)
crossfade_pos = 0;
}
pcmbuf_flush_buffer(buf, length);
}
static bool prepare_insert(size_t length)
{
if (crossfade_init)
crossfade_start();
if (low_latency_mode)
{
/* 1/4s latency. */
if (pcmbuf_unplayed_bytes > NATIVE_FREQUENCY * 4 / 4
&& pcm_is_playing())
return false;
}
/* Need to save PCMBUF_MIN_CHUNK to prevent wrapping overwriting */
if (audiobuffer_free < length + PCMBUF_MIN_CHUNK && !crossfade_active)
{
pcmbuf_boost(false);
return false;
}
if (!pcm_is_playing())
{
pcmbuf_boost(true);
crossfade_active = false;
/* Pre-buffer 1s. */
if (!LOW_DATA(4))
{
logf("pcm starting");
pcmbuf_play_start();
}
} else if (pcmbuf_unplayed_bytes <= pcmbuf_watermark)
pcmbuf_under_watermark();
return true;
}
void* pcmbuf_request_buffer(size_t length, size_t *realsize)
{
if (crossfade_active) {
*realsize = MIN(length, PCMBUF_FADE_CHUNK);
return &guardbuf[0];
}
else
{
if(prepare_insert(length))
{
size_t audiobuffer_index = audiobuffer_pos + audiobuffer_fillpos;
*realsize = length;
if (pcmbuf_size - audiobuffer_index >= PCMBUF_MIN_CHUNK)
{
/* Usual case, there's space here */
return &audiobuffer[audiobuffer_index];
}
else
{
/* Flush and wrap the buffer */
pcmbuf_flush_fillpos();
audiobuffer_pos = 0;
return &audiobuffer[0];
}
}
else
{
*realsize = 0;
return NULL;
}
}
}
void* pcmbuf_request_voice_buffer(size_t length, size_t *realsize, bool mix)
{
if (mix)
{
*realsize = MIN(length, PCMBUF_FADE_CHUNK);
return &guardbuf[0];
}
else
return pcmbuf_request_buffer(length, realsize);
}
bool pcmbuf_is_crossfade_active(void)
{
return crossfade_active || crossfade_init;
}
void pcmbuf_write_complete(size_t length)
{
if (crossfade_active) {
length = MIN(length, PCMBUF_FADE_CHUNK);
flush_crossfade(&guardbuf[0],length);
}
else
{
audiobuffer_free -= length;
audiobuffer_fillpos += length;
if (NEED_FLUSH(audiobuffer_pos + audiobuffer_fillpos))
pcmbuf_flush_fillpos();
}
}
bool pcmbuf_insert_buffer(const char *buf, size_t length)
{
if (!prepare_insert(length))
return false;
if (crossfade_active) {
flush_crossfade(buf,length);
}
else
{
pcmbuf_flush_buffer(buf, length);
}
return true;
}
/* Get a pointer to where to mix immediate audio */
static inline short* get_mix_insert_pos(void) {
/* Give at least 1/8s clearance here */
size_t pcmbuf_mix_back_pos =
pcmbuf_unplayed_bytes - NATIVE_FREQUENCY * 4 / 8;
if (audiobuffer_pos < pcmbuf_mix_back_pos)
return (short *)&audiobuffer[pcmbuf_size +
audiobuffer_pos - pcmbuf_mix_back_pos];
else
return (short *)&audiobuffer[audiobuffer_pos - pcmbuf_mix_back_pos];
}
/* Generates a constant square wave sound with a given frequency
in Hertz for a duration in milliseconds. */
void pcmbuf_beep(unsigned int frequency, size_t duration, int amplitude)
{
unsigned int count = 0, i = 0;
bool state = false;
unsigned int interval = NATIVE_FREQUENCY / frequency;
short *buf;
short *pcmbuf_end = (short *)guardbuf;
bool playing = pcm_is_playing();
size_t samples = NATIVE_FREQUENCY / 1000 * duration;
if (playing) {
buf = get_mix_insert_pos();
} else {
buf = (short *)audiobuffer;
}
while (i++ < samples)
{
long sample = *buf;
if (state) {
*buf++ = MIN(MAX(sample + amplitude, -32768), 32767);
if (buf > pcmbuf_end)
buf = (short *)audiobuffer;
sample = *buf;
*buf++ = MIN(MAX(sample + amplitude, -32768), 32767);
} else {
*buf++ = MIN(MAX(sample - amplitude, -32768), 32767);
if (buf > pcmbuf_end)
buf = (short *)audiobuffer;
sample = *buf;
*buf++ = MIN(MAX(sample - amplitude, -32768), 32767);
}
if (++count >= interval)
{
count = 0;
state = !state;
}
if (buf > pcmbuf_end)
buf = (short *)audiobuffer;
}
if (!playing) {
pcm_play_data(NULL, (unsigned char *)audiobuffer, samples * 4);
}
}
/* Returns pcm buffer usage in percents (0 to 100). */
int pcmbuf_usage(void)
{
return pcmbuf_unplayed_bytes * 100 / pcmbuf_size;
}
int pcmbuf_mix_usage(void)
{
return pcmbuf_mix_used_bytes * 100 / pcmbuf_unplayed_bytes;
}
void pcmbuf_reset_mixpos(void)
{
mixpos = get_mix_insert_pos();
pcmbuf_mix_used_bytes = 0;
}
void pcmbuf_mix(char *buf, size_t length)
{
short *ibuf = (short *)buf;
short *pcmbuf_end = (short *)guardbuf;
if (pcmbuf_mix_used_bytes == 0)
pcmbuf_reset_mixpos();
pcmbuf_mix_used_bytes += length;
length /= 2;
while (length-- > 0) {
long sample = *ibuf++;
sample += *mixpos >> 2;
*mixpos++ = MIN(MAX(sample, -32768), 32767);
if (mixpos >= pcmbuf_end)
mixpos = (short *)audiobuffer;
}
}
void pcmbuf_crossfade_enable(bool on_off)
{
crossfade_enabled = on_off;
if (crossfade_enabled) {
/* If crossfading, try to keep the buffer full other than 2 second */
pcmbuf_set_watermark_bytes(pcmbuf_size - PCMBUF_WATERMARK * 2);
} else {
/* Otherwise, just keep it above 1 second */
pcmbuf_set_watermark_bytes(PCMBUF_WATERMARK);
}
}
bool pcmbuf_is_crossfade_enabled(void)
{
if (global_settings.crossfade == CROSSFADE_ENABLE_SHUFFLE)
return global_settings.playlist_shuffle;
return crossfade_enabled;
}
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