/* * Copyright (C) 2003-2009 The Music Player Daemon Project * http://www.musicpd.org * * 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 program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "crossfade.h" #include "pcm_mix.h" #include "chunk.h" #include "audio_format.h" #include "tag.h" #include <assert.h> #include <string.h> unsigned cross_fade_calc(float duration, float total_time, const struct audio_format *af, const struct audio_format *old_format, unsigned max_chunks) { unsigned int chunks; 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); if (chunks > max_chunks) chunks = max_chunks; 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; } }