Audinaut-subsonic-app-android/app/src/main/java/net/nullsum/audinaut/util/tags/LameHeader.java

71 lines
2.3 KiB
Java

/*
* Copyright (C) 2013 Adrian Ulrich <adrian@blinkenlights.ch>
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*/
package net.nullsum.audinaut.util.tags;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.charset.StandardCharsets;
import java.util.HashMap;
class LameHeader extends Common {
public LameHeader() {
}
public HashMap getTags(RandomAccessFile s) throws IOException {
return parseLameHeader(s, 0);
}
public HashMap parseLameHeader(RandomAccessFile s, long offset) throws IOException {
HashMap tags = new HashMap();
byte[] chunk = new byte[4];
s.seek(offset + 0x24);
s.read(chunk);
String lameMark = new String(chunk, 0, chunk.length, StandardCharsets.ISO_8859_1);
if (lameMark.equals("Info") || lameMark.equals("Xing")) {
s.seek(offset + 0xAB);
s.read(chunk);
int raw = b2be32(chunk, 0);
int gtrk_raw = raw >> 16; /* first 16 bits are the raw track gain value */
int galb_raw = raw & 0xFFFF; /* the rest is for the album gain value */
float gtrk_val = (float) (gtrk_raw & 0x01FF) / 10;
float galb_val = (float) (galb_raw & 0x01FF) / 10;
gtrk_val = ((gtrk_raw & 0x0200) != 0 ? -1 * gtrk_val : gtrk_val);
galb_val = ((galb_raw & 0x0200) != 0 ? -1 * galb_val : galb_val);
if ((gtrk_raw & 0xE000) == 0x2000) {
addTagEntry(tags, "REPLAYGAIN_TRACK_GAIN", gtrk_val + " dB");
}
if ((gtrk_raw & 0xE000) == 0x4000) {
addTagEntry(tags, "REPLAYGAIN_ALBUM_GAIN", galb_val + " dB");
}
}
return tags;
}
}