diff options
Diffstat (limited to 'src/crossfade.c')
| -rw-r--r-- | src/crossfade.c | 150 |
1 files changed, 95 insertions, 55 deletions
diff --git a/src/crossfade.c b/src/crossfade.c index 01552bf65..cdfd82879 100644 --- a/src/crossfade.c +++ b/src/crossfade.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2003-2009 The Music Player Daemon Project + * Copyright (C) 2003-2010 The Music Player Daemon Project * http://www.musicpd.org * * This program is free software; you can redistribute it and/or modify @@ -17,6 +17,7 @@ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ +#include "config.h" #include "crossfade.h" #include "pcm_mix.h" #include "chunk.h" @@ -25,73 +26,112 @@ #include <assert.h> #include <string.h> +#include <stdlib.h> +#include <glib.h> + +#undef G_LOG_DOMAIN +#define G_LOG_DOMAIN "crossfade" + +#ifdef G_OS_WIN32 +static char * +strtok_r(char *str, const char *delim, G_GNUC_UNUSED char **saveptr) +{ + return strtok(str, delim); +} +#endif + +static float mixramp_interpolate(char *ramp_list, float required_db) +{ + float db, secs, last_db = nan(""), last_secs = 0; + char *ramp_str, *save_str = NULL; + + /* ramp_list is a string of pairs of dBs and seconds that describe the + * volume profile. Delimiters are semi-colons between pairs and spaces + * between the dB and seconds of a pair. + * The dB values must be monotonically increasing for this to work. */ + + while (1) { + /* Parse the dB tokens out of the input string. */ + ramp_str = strtok_r(ramp_list, " ", &save_str); + + /* Tell strtok to continue next time round. */ + ramp_list = NULL; + + /* Parse the dB value. */ + if (NULL == ramp_str) { + return nan(""); + } + db = (float)atof(ramp_str); + + /* Parse the time. */ + ramp_str = strtok_r(NULL, ";", &save_str); + if (NULL == ramp_str) { + return nan(""); + } + secs = (float)atof(ramp_str); + + /* Check for exact match. */ + if (db == required_db) { + return secs; + } + + /* Save if too quiet. */ + if (db < required_db) { + last_db = db; + last_secs = secs; + continue; + } + + /* If required db < any stored value, use the least. */ + if (isnan(last_db)) { + return secs; + } + + /* Finally, interpolate linearly. */ + secs = last_secs + (required_db - last_db) * (secs - last_secs) / (db - last_db); + return secs; + } +} unsigned cross_fade_calc(float duration, float total_time, + float mixramp_db, float mixramp_delay, + float replay_gain_db, float replay_gain_prev_db, + char *mixramp_start, char *mixramp_prev_end, const struct audio_format *af, const struct audio_format *old_format, unsigned max_chunks) { - unsigned int chunks; + unsigned int chunks = 0; + float chunks_f; + float mixramp_overlap; - if (duration <= 0 || duration >= total_time || + if (duration < 0 || duration >= total_time || /* we can't crossfade when the audio formats are different */ !audio_format_equals(af, old_format)) return 0; - assert(duration > 0); - assert(af->bits > 0); - assert(af->channels > 0); - assert(af->sample_rate > 0); - - chunks = audio_format_time_to_size(af) / CHUNK_SIZE; - chunks = (chunks * duration + 0.5); + assert(duration >= 0); + assert(audio_format_valid(af)); + + chunks_f = (float)audio_format_time_to_size(af) / (float)CHUNK_SIZE; + + if (isnan(mixramp_delay) || !(mixramp_start) || !(mixramp_prev_end)) { + chunks = (chunks_f * duration + 0.5); + } else { + /* Calculate mixramp overlap. */ + mixramp_overlap = mixramp_interpolate(mixramp_start, mixramp_db - replay_gain_db) + + mixramp_interpolate(mixramp_prev_end, mixramp_db - replay_gain_prev_db); + if (!isnan(mixramp_overlap) && (mixramp_delay <= mixramp_overlap)) { + chunks = (chunks_f * (mixramp_overlap - mixramp_delay)); + g_debug("will overlap %d chunks, %fs", chunks, + mixramp_overlap - mixramp_delay); + } + } - if (chunks > max_chunks) + if (chunks > max_chunks) { chunks = max_chunks; + g_warning("audio_buffer_size too small for computed MixRamp overlap"); + } return chunks; } - -void cross_fade_apply(struct music_chunk *a, const struct music_chunk *b, - const struct audio_format *format, - unsigned int current_chunk, unsigned int num_chunks) -{ - size_t size; - - assert(a != NULL); - assert(b != NULL); - assert(a->length == 0 || b->length == 0 || - audio_format_equals(&a->audio_format, &b->audio_format)); - assert(current_chunk <= num_chunks); - - if (a->tag == NULL && b->tag != NULL) - /* merge the tag into the destination chunk */ - a->tag = tag_dup(b->tag); - - size = b->length > a->length - ? a->length - : b->length; - - pcm_mix(a->data, - b->data, - size, - format, - ((float)current_chunk) / num_chunks); - - if (b->length > a->length) { - /* the second buffer is larger than the first one: - there is unmixed rest at the end. Copy it over. - The output buffer API guarantees that there is - enough room in a->data. */ - -#ifndef NDEBUG - if (a->length == 0) - a->audio_format = b->audio_format; -#endif - - memcpy(a->data + a->length, - b->data + a->length, - b->length - a->length); - a->length = b->length; - } -} |