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author | Max Kellermann <max@duempel.org> | 2010-07-20 18:38:10 +0200 |
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committer | Max Kellermann <max@duempel.org> | 2010-07-20 23:03:54 +0200 |
commit | 4364b30c423d230568a4b4f47a0e3b5fa9ff831b (patch) | |
tree | bf37bb9e18be66dce0fb23ccd99198c9efa408a6 /src/tag_rva2.c | |
parent | c0da938d4f9e6b15cc5cca80090a15aa89ff3d2b (diff) | |
download | mpd-4364b30c423d230568a4b4f47a0e3b5fa9ff831b.tar.gz mpd-4364b30c423d230568a4b4f47a0e3b5fa9ff831b.tar.xz mpd-4364b30c423d230568a4b4f47a0e3b5fa9ff831b.zip |
decoder/mad: move RVA2 code to tag_rva2.c
Diffstat (limited to '')
-rw-r--r-- | src/tag_rva2.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/src/tag_rva2.c b/src/tag_rva2.c new file mode 100644 index 000000000..28002025b --- /dev/null +++ b/src/tag_rva2.c @@ -0,0 +1,110 @@ +/* + * 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 + * 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 "tag_rva2.h" +#include "replay_gain_info.h" + +#include <glib.h> +#include <id3tag.h> + +bool +tag_rva2_parse(struct id3_tag *tag, struct replay_gain_info *replay_gain_info) +{ + struct id3_frame const * frame; + + id3_latin1_t const *id; + id3_byte_t const *data; + id3_length_t length; + + enum { + 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 + }; + + /* relative volume adjustment information */ + + frame = id3_tag_findframe(tag, "RVA2", 0); + if (frame == NULL) + return false; + + id = id3_field_getlatin1(id3_frame_field(frame, 0)); + data = id3_field_getbinarydata(id3_frame_field(frame, 1), + &length); + + if (id == NULL || data == NULL) + 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) { + unsigned int peak_bytes; + + peak_bytes = (data[3] + 7) / 8; + if (4 + peak_bytes > length) + break; + + if (data[0] == CHANNEL_MASTER_VOLUME) { + signed int voladj_fixed; + double voladj_float; + + /* + * "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." + */ + + voladj_fixed = (data[1] << 8) | (data[2] << 0); + voladj_fixed |= -(voladj_fixed & 0x8000); + + voladj_float = (double) voladj_fixed / 512; + + replay_gain_info->tuples[REPLAY_GAIN_TRACK].gain = voladj_float; + replay_gain_info->tuples[REPLAY_GAIN_ALBUM].gain = voladj_float; + + g_debug("parseRVA2: Relative Volume " + "%+.1f dB adjustment (%s)\n", + voladj_float, id); + + return true; + } + + data += 4 + peak_bytes; + length -= 4 + peak_bytes; + } + + return false; +} |