2 * Sonitus - Frame.java - Copyright © 2013 David Roden
4 * This program is free software: you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation, either version 3 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 package net.pterodactylus.sonitus.io.mp3;
22 import com.google.common.base.Optional;
23 import com.google.common.base.Supplier;
24 import com.google.common.base.Suppliers;
25 import com.google.common.collect.ImmutableBiMap;
26 import com.google.common.collect.ImmutableMap;
29 * A single MPEG audio frame.
31 * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
35 /** The MPEG audio version. */
36 public enum MpegAudioVersion {
52 /** The MPEG layer description. */
53 public enum LayerDescription {
69 /** The channel mode. */
70 public enum ChannelMode {
78 /** Dual-channel stereo. */
81 /** Single channel, aka mono. */
86 /** Mode of emphasis. */
87 public enum Emphasis {
103 /** Bitrate table. */
104 private static final Supplier<Map<MpegAudioVersion, Map<LayerDescription, Map<Integer, Integer>>>> bitrateSupplier = Suppliers.memoize(new Supplier<Map<MpegAudioVersion, Map<LayerDescription, Map<Integer, Integer>>>>() {
107 public Map<MpegAudioVersion, Map<LayerDescription, Map<Integer, Integer>>> get() {
108 ImmutableMap.Builder<MpegAudioVersion, Map<LayerDescription, Map<Integer, Integer>>> mpegAudioVersionMapBuilder = ImmutableMap.builder();
111 ImmutableMap.Builder<LayerDescription, Map<Integer, Integer>> mpeg1Builder = ImmutableMap.builder();
114 ImmutableMap.Builder<Integer, Integer> bitrates = ImmutableMap.builder();
115 bitrates.put(0, 0).put(1, 32).put(2, 64).put(3, 96).put(4, 128).put(5, 160).put(6, 192).put(7, 224);
116 bitrates.put(8, 256).put(9, 288).put(10, 320).put(11, 352).put(12, 384).put(13, 416).put(14, 448).put(15, -1);
117 mpeg1Builder.put(LayerDescription.LAYER_1, bitrates.build());
119 /* MPEG 1, Layer 2 bitrates. */
120 bitrates = ImmutableMap.builder();
121 bitrates.put(0, 0).put(1, 32).put(2, 48).put(3, 56).put(4, 64).put(5, 80).put(6, 96).put(7, 112);
122 bitrates.put(8, 128).put(9, 160).put(10, 192).put(11, 224).put(12, 256).put(13, 320).put(14, 384).put(15, -1);
123 mpeg1Builder.put(LayerDescription.LAYER_2, bitrates.build());
125 /* MPEG 1, Layer 3 bitrates. */
126 bitrates = ImmutableMap.builder();
127 bitrates.put(0, 0).put(1, 32).put(2, 40).put(3, 48).put(4, 56).put(5, 64).put(6, 80).put(7, 96);
128 bitrates.put(8, 112).put(9, 128).put(10, 160).put(11, 192).put(12, 224).put(13, 256).put(14, 320).put(15, -1);
129 mpeg1Builder.put(LayerDescription.LAYER_3, bitrates.build());
130 mpegAudioVersionMapBuilder.put(MpegAudioVersion.VERSION_1, mpeg1Builder.build());
133 ImmutableBiMap.Builder<LayerDescription, Map<Integer, Integer>> mpeg2Builder = ImmutableBiMap.builder();
136 bitrates = ImmutableMap.builder();
137 bitrates.put(0, 0).put(1, 32).put(2, 48).put(3, 56).put(4, 64).put(5, 80).put(6, 96).put(7, 112);
138 bitrates.put(8, 128).put(9, 144).put(10, 160).put(11, 176).put(12, 192).put(13, 224).put(14, 256).put(15, -1);
139 mpeg2Builder.put(LayerDescription.LAYER_1, bitrates.build());
142 bitrates = ImmutableMap.builder();
143 bitrates.put(0, 0).put(1, 8).put(2, 16).put(3, 24).put(4, 32).put(5, 40).put(6, 48).put(7, 56);
144 bitrates.put(8, 64).put(9, 80).put(10, 96).put(11, 112).put(12, 128).put(13, 144).put(14, 160).put(15, -1);
145 mpeg2Builder.put(LayerDescription.LAYER_2, bitrates.build());
146 mpeg2Builder.put(LayerDescription.LAYER_3, bitrates.build());
148 mpegAudioVersionMapBuilder.put(MpegAudioVersion.VERSION_2, mpeg2Builder.build());
149 mpegAudioVersionMapBuilder.put(MpegAudioVersion.VERSION_2_5, mpeg2Builder.build());
151 return mpegAudioVersionMapBuilder.build();
155 /** Sampling rate table. */
156 private static final Supplier<Map<MpegAudioVersion, Map<Integer, Integer>>> samplingRateSupplier = Suppliers.memoize(new Supplier<Map<MpegAudioVersion, Map<Integer, Integer>>>() {
159 public Map<MpegAudioVersion, Map<Integer, Integer>> get() {
160 ImmutableMap.Builder<MpegAudioVersion, Map<Integer, Integer>> mpegAudioVersions = ImmutableMap.builder();
163 ImmutableMap.Builder<Integer, Integer> samplingRates = ImmutableMap.builder();
164 samplingRates.put(0, 44100).put(1, 48000).put(2, 32000).put(3, 0);
165 mpegAudioVersions.put(MpegAudioVersion.VERSION_1, samplingRates.build());
168 samplingRates = ImmutableMap.builder();
169 samplingRates.put(0, 22050).put(1, 24000).put(2, 16000).put(3, 0);
170 mpegAudioVersions.put(MpegAudioVersion.VERSION_2, samplingRates.build());
173 samplingRates = ImmutableMap.builder();
174 samplingRates.put(0, 11025).put(1, 12000).put(2, 8000).put(3, 0);
175 mpegAudioVersions.put(MpegAudioVersion.VERSION_2_5, samplingRates.build());
177 return mpegAudioVersions.build();
181 /** The decoded MPEG audio version ID. */
182 private final int mpegAudioVersionId;
184 /** The decoded layer description. */
185 private final int layerDescription;
187 /** The decoded protection bit. */
188 private final int protectionBit;
190 /** The decoded bitrate index. */
191 private final int bitrateIndex;
193 /** The deocded sampling rate frequency index. */
194 private final int samplingRateFrequencyIndex;
196 /** The decoded padding bit. */
197 private final int paddingBit;
199 /** The decoded private bit. */
200 private final int privateBit;
202 /** The decoded channel mode. */
203 private final int channelMode;
205 /** The deocded mode extension. */
206 private final int modeExtension;
208 /** The decoded copyright bit. */
209 private final int copyright;
211 /** The deocded original bit. */
212 private final int original;
214 /** The decoded emphasis mode. */
215 private final int emphasis;
217 private Frame(int mpegAudioVersionId, int layerDescription, int protectionBit, int bitrateIndex, int samplingRateFrequencyIndex, int paddingBit, int privateBit, int channelMode, int modeExtension, int copyright, int original, int emphasis) {
218 this.mpegAudioVersionId = mpegAudioVersionId;
219 this.layerDescription = layerDescription;
220 this.protectionBit = protectionBit;
221 this.bitrateIndex = bitrateIndex;
222 this.samplingRateFrequencyIndex = samplingRateFrequencyIndex;
223 this.paddingBit = paddingBit;
224 this.privateBit = privateBit;
225 this.channelMode = channelMode;
226 this.modeExtension = modeExtension;
227 this.copyright = copyright;
228 this.original = original;
229 this.emphasis = emphasis;
236 public MpegAudioVersion mpegAudioVersion() {
237 return MpegAudioVersion.values()[mpegAudioVersionId];
240 public LayerDescription layerDescription() {
241 return LayerDescription.values()[layerDescription];
244 public boolean protectionBit() {
245 return protectionBit != 0;
248 public int bitrate() {
249 return bitrateSupplier.get().get(mpegAudioVersion()).get(layerDescription()).get(bitrateIndex);
252 public int samplingRate() {
253 return samplingRateSupplier.get().get(mpegAudioVersion()).get(samplingRateFrequencyIndex);
256 public boolean paddingBit() {
257 return paddingBit != 0;
260 public boolean privateBit() {
261 return privateBit != 0;
264 public ChannelMode channelMode() {
265 return ChannelMode.values()[channelMode];
268 /* TODO - mode extension. */
270 public boolean copyrightBit() {
271 return copyright != 0;
274 public boolean originalBit() {
275 return original != 0;
278 public Emphasis emphasis() {
279 return Emphasis.values()[emphasis];
286 public static boolean isFrame(byte[] buffer, int offset, int length) {
287 return (((buffer[offset] & 0xff) == 0xff) && ((buffer[offset + 1] & 0xe0) == 0xe0));
290 public static Optional<Frame> create(byte[] buffer, int offset, int length) {
291 if (isFrame(buffer, offset, length)) {
292 int mpegAudioVersionId = (buffer[offset + 1] & 0x18) >>> 3;
293 int layerDescription = (buffer[offset + 1] & 0x06) >>> 1;
294 int protectionBit = buffer[offset + 1] & 0x01;
295 int bitrateIndex = (buffer[offset + 2] & 0xf0) >>> 4;
296 int samplingRateFrequencyIndex = (buffer[offset + 2] & 0x0c) >>> 2;
297 int paddingBit = (buffer[offset + 2] & 0x02) >>> 1;
298 int privateBit = buffer[offset + 2] & 0x01;
299 int channelMode = (buffer[offset + 3] & 0xc0) >> 6;
300 int modeExtension = (buffer[offset + 3] & 0x60) >> 4;
301 int copyright = (buffer[offset + 3] & 0x08) >> 3;
302 int original = (buffer[offset + 3] & 0x04) >> 2;
303 int emphasis = buffer[offset + 3] & 0x03;
304 return Optional.of(new Frame(mpegAudioVersionId, layerDescription, protectionBit, bitrateIndex, samplingRateFrequencyIndex, paddingBit, privateBit, channelMode, modeExtension, copyright, original, emphasis));
306 return Optional.absent();