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author | Max Kellermann <max@duempel.org> | 2015-08-15 15:55:46 +0200 |
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committer | Max Kellermann <max@duempel.org> | 2015-08-15 15:55:46 +0200 |
commit | 5fba8d773c3f6ea35a2934baa91372806f1c9940 (patch) | |
tree | 8afb1d6383f4bac521b7aa544f823a698e5a479d /src/player/CrossFade.cxx | |
parent | 36cd73df51c6bae6b283f1bf14704d86ad98b3c5 (diff) | |
download | mpd-5fba8d773c3f6ea35a2934baa91372806f1c9940.tar.gz mpd-5fba8d773c3f6ea35a2934baa91372806f1c9940.tar.xz mpd-5fba8d773c3f6ea35a2934baa91372806f1c9940.zip |
PlayerThread, ...: move to src/player/
Diffstat (limited to 'src/player/CrossFade.cxx')
-rw-r--r-- | src/player/CrossFade.cxx | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/src/player/CrossFade.cxx b/src/player/CrossFade.cxx new file mode 100644 index 000000000..6d7b41440 --- /dev/null +++ b/src/player/CrossFade.cxx @@ -0,0 +1,140 @@ +/* + * Copyright (C) 2003-2015 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 "config.h" +#include "CrossFade.hxx" +#include "Chrono.hxx" +#include "MusicChunk.hxx" +#include "AudioFormat.hxx" +#include "util/NumberParser.hxx" +#include "util/Domain.hxx" +#include "Log.hxx" + +#include <assert.h> + +static constexpr Domain cross_fade_domain("cross_fade"); + +gcc_pure +static float +mixramp_interpolate(const char *ramp_list, float required_db) +{ + float last_db = 0, last_secs = 0; + bool have_last = false; + + /* 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 value. */ + char *endptr; + const float db = ParseFloat(ramp_list, &endptr); + if (endptr == ramp_list || *endptr != ' ') + break; + + ramp_list = endptr + 1; + + /* Parse the time. */ + float secs = ParseFloat(ramp_list, &endptr); + if (endptr == ramp_list || (*endptr != ';' && *endptr != 0)) + break; + + ramp_list = endptr; + if (*ramp_list == ';') + ++ramp_list; + + /* Check for exact match. */ + if (db == required_db) { + return secs; + } + + /* Save if too quiet. */ + if (db < required_db) { + last_db = db; + last_secs = secs; + have_last = true; + continue; + } + + /* If required db < any stored value, use the least. */ + if (!have_last) + return secs; + + /* Finally, interpolate linearly. */ + secs = last_secs + (required_db - last_db) * (secs - last_secs) / (db - last_db); + return secs; + } + + return -1; +} + +unsigned +CrossFadeSettings::Calculate(SignedSongTime total_time, + float replay_gain_db, float replay_gain_prev_db, + const char *mixramp_start, const char *mixramp_prev_end, + const AudioFormat af, + const AudioFormat old_format, + unsigned max_chunks) const +{ + unsigned int chunks = 0; + float chunks_f; + + if (total_time.IsNegative() || + duration < 0 || duration >= total_time.ToDoubleS() || + /* we can't crossfade when the audio formats are different */ + af != old_format) + return 0; + + assert(duration >= 0); + assert(af.IsValid()); + + chunks_f = (float)af.GetTimeToSize() / (float)CHUNK_SIZE; + + if (mixramp_delay <= 0 || !mixramp_start || !mixramp_prev_end) { + chunks = (chunks_f * duration + 0.5); + } else { + /* Calculate mixramp overlap. */ + const float mixramp_overlap_current = + mixramp_interpolate(mixramp_start, + mixramp_db - replay_gain_db); + const float mixramp_overlap_prev = + mixramp_interpolate(mixramp_prev_end, + mixramp_db - replay_gain_prev_db); + const float mixramp_overlap = + mixramp_overlap_current + mixramp_overlap_prev; + + if (mixramp_overlap_current >= 0 && + mixramp_overlap_prev >= 0 && + mixramp_delay <= mixramp_overlap) { + chunks = (chunks_f * (mixramp_overlap - mixramp_delay)); + FormatDebug(cross_fade_domain, + "will overlap %d chunks, %fs", chunks, + mixramp_overlap - mixramp_delay); + } + } + + if (chunks > max_chunks) { + chunks = max_chunks; + LogWarning(cross_fade_domain, + "audio_buffer_size too small for computed MixRamp overlap"); + } + + return chunks; +} |