/*************************************************************************** * __________ __ ___. * 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 #include #include "config.h" #include "debug.h" #include "panic.h" #include #include "pcmbuf.h" #include "pcm_playback.h" #include "logf.h" #ifndef SIMULATOR #include "cpu.h" #endif #include "system.h" #include #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) { if (pause) pcm_mute(true); pcm_play_pause(!pause); if (!pause) pcm_mute(false); 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); /* If this happens, something is being stupid */ if (!pcm_is_playing()) { logf("pcmbuf_flush_fillpos error"); pcmbuf_play_start(); } /* Let approximately one chunk of data playback */ sleep(PCMBUF_TARGET_CHUNK/(NATIVE_FREQUENCY * 4) / 5); } pcmbuf_add_chunk(); } mutex_unlock(&pcmbuf_mutex); } /** * Completely process the crossfade fade out effect with current pcm buffer. */ static void crossfade_process_buffer(size_t fade_in_delay, size_t fade_out_delay, size_t fade_out_rem) { if (crossfade_mode == CFM_CROSSFADE) { /* Fade out the specified amount of the already processed audio */ size_t total_fade_out = fade_out_rem; short *buf = (short *)&audiobuffer[crossfade_pos + fade_out_delay * 2]; short *buf_end = (short *)guardbuf; /* Wrap the starting position if needed */ if (buf >= buf_end) buf -= pcmbuf_size / 2; while (fade_out_rem > 0) { /* Each 1/10 second of audio will have the same fade applied */ size_t block_rem = MIN(NATIVE_FREQUENCY * 2 / 10, fade_out_rem); unsigned int factor = (fade_out_rem << 8) / total_fade_out; short *block_end = buf + block_rem; fade_out_rem -= block_rem; /* Fade this block */ while (buf < block_end) { /* Fade one sample */ *buf = (*buf * factor) >> 8; buf++; if (buf >= buf_end) { /* Wrap the pcmbuffer */ buf -= pcmbuf_size / 2; /* Wrap the end pointer to ensure proper termination */ block_end -= pcmbuf_size / 2; } } } } /* 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; }