From 5101ef4b028c8f661801f78ba0fe73fab0e80f7f Mon Sep 17 00:00:00 2001 From: Max Kellermann Date: Wed, 4 Sep 2013 23:46:20 +0200 Subject: Tag*: move libtag.a sources to src/tag/ --- src/tag/TagRva2.cxx | 150 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 150 insertions(+) create mode 100644 src/tag/TagRva2.cxx (limited to 'src/tag/TagRva2.cxx') diff --git a/src/tag/TagRva2.cxx b/src/tag/TagRva2.cxx new file mode 100644 index 000000000..f41119c35 --- /dev/null +++ b/src/tag/TagRva2.cxx @@ -0,0 +1,150 @@ +/* + * Copyright (C) 2003-2013 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 "TagRva2.hxx" +#include "replay_gain_info.h" + +#include +#include +#include +#include + +enum rva2_channel { + CHANNEL_OTHER = 0x00, + CHANNEL_MASTER_VOLUME = 0x01, + CHANNEL_FRONT_RIGHT = 0x02, + CHANNEL_FRONT_LEFT = 0x03, + CHANNEL_BACK_RIGHT = 0x04, + CHANNEL_BACK_LEFT = 0x05, + CHANNEL_FRONT_CENTRE = 0x06, + CHANNEL_BACK_CENTRE = 0x07, + CHANNEL_SUBWOOFER = 0x08 +}; + +struct rva2_data { + uint8_t type; + uint8_t volume_adjustment[2]; + uint8_t peak_bits; +}; + +static inline id3_length_t +rva2_peak_bytes(const struct rva2_data *data) +{ + return (data->peak_bits + 7) / 8; +} + +static inline int +rva2_fixed_volume_adjustment(const struct rva2_data *data) +{ + signed int voladj_fixed; + voladj_fixed = (data->volume_adjustment[0] << 8) | + data->volume_adjustment[1]; + voladj_fixed |= -(voladj_fixed & 0x8000); + return voladj_fixed; +} + +static inline float +rva2_float_volume_adjustment(const struct rva2_data *data) +{ + /* + * "The volume adjustment is encoded as a fixed point decibel + * value, 16 bit signed integer representing (adjustment*512), + * giving +/- 64 dB with a precision of 0.001953125 dB." + */ + + return (float)rva2_fixed_volume_adjustment(data) / (float)512; +} + +static inline bool +rva2_apply_data(struct replay_gain_info *replay_gain_info, + const struct rva2_data *data, const id3_latin1_t *id) +{ + if (data->type != CHANNEL_MASTER_VOLUME) + return false; + + float volume_adjustment = rva2_float_volume_adjustment(data); + + if (strcmp((const char *)id, "album") == 0) { + replay_gain_info->tuples[REPLAY_GAIN_ALBUM].gain = volume_adjustment; + } else if (strcmp((const char *)id, "track") == 0) { + replay_gain_info->tuples[REPLAY_GAIN_TRACK].gain = volume_adjustment; + } else { + replay_gain_info->tuples[REPLAY_GAIN_ALBUM].gain = volume_adjustment; + replay_gain_info->tuples[REPLAY_GAIN_TRACK].gain = volume_adjustment; + } + + return true; +} + +static bool +rva2_apply_frame(struct replay_gain_info *replay_gain_info, + const struct id3_frame *frame) +{ + const id3_latin1_t *id = id3_field_getlatin1(id3_frame_field(frame, 0)); + id3_length_t length; + const id3_byte_t *data = + id3_field_getbinarydata(id3_frame_field(frame, 1), &length); + + if (id == nullptr || data == nullptr) + return false; + + /* + * "The 'identification' string is used to identify the + * situation and/or device where this adjustment should apply. + * The following is then repeated for every channel + * + * Type of channel $xx + * Volume adjustment $xx xx + * Bits representing peak $xx + * Peak volume $xx (xx ...)" + */ + + while (length >= 4) { + const struct rva2_data *d = (const struct rva2_data *)data; + unsigned int peak_bytes = rva2_peak_bytes(d); + if (4 + peak_bytes > length) + break; + + if (rva2_apply_data(replay_gain_info, d, id)) + return true; + + data += 4 + peak_bytes; + length -= 4 + peak_bytes; + } + + return false; +} + +bool +tag_rva2_parse(struct id3_tag *tag, struct replay_gain_info *replay_gain_info) +{ + bool found = false; + + /* Loop through all RVA2 frames as some programs (e.g. mp3gain) store + track and album gain in separate tags */ + const struct id3_frame *frame; + for (unsigned i = 0; + (frame = id3_tag_findframe(tag, "RVA2", i)) != nullptr; + ++i) + if (rva2_apply_frame(replay_gain_info, frame)) + found = true; + + return found; +} -- cgit v1.2.3