2 * Sonitus - ResampleFilter.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.data.filter;
20 import static com.google.common.base.Preconditions.checkArgument;
21 import static com.google.common.base.Preconditions.checkNotNull;
23 import java.io.IOException;
25 import net.pterodactylus.sonitus.data.Metadata;
27 import com.google.common.collect.ImmutableList;
28 import com.google.common.eventbus.EventBus;
31 * {@link net.pterodactylus.sonitus.data.Filter} implementation that uses {@code
32 * sox} to resample a PCM-encoded source.
34 * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
36 public class SoxResampleFilter extends ExternalFilter {
38 /** The location of the binary. */
39 private final String binary;
41 /** The final sampling rate. */
42 private final int rate;
45 * Creates a new resample filter.
50 * The location of the binary
52 * The new sampling rate
54 public SoxResampleFilter(EventBus eventBus, String binary, int rate) {
55 super(eventBus, String.format("Resample to %s kHz", rate / 1000.0));
65 public Metadata metadata() {
66 return super.metadata().frequency(rate);
70 public void open(Metadata metadata) throws IOException {
71 checkNotNull(metadata, "metadata must not be null");
72 checkArgument(metadata.encoding().equalsIgnoreCase("PCM"), "source must be PCM-encoded");
78 // EXTERNALFILTER METHODS
82 protected String binary(Metadata metadata) {
87 protected Iterable<String> parameters(Metadata metadata) {
88 ImmutableList.Builder<String> parameters = ImmutableList.builder();
90 parameters.add("--bits").add("16");
91 parameters.add("--channels").add(String.valueOf(metadata.channels()));
92 parameters.add("--encoding").add("signed-integer");
93 parameters.add("--rate").add(String.valueOf(metadata.frequency()));
94 parameters.add("--type").add("raw");
95 parameters.add("--endian").add("little");
97 /* the output file. */
98 parameters.add("--bits").add("16");
99 parameters.add("--channels").add(String.valueOf(metadata.channels()));
100 parameters.add("--encoding").add("signed-integer");
101 parameters.add("--type").add("raw");
102 parameters.add("--endian").add("little");
105 parameters.add("rate").add("-h").add(String.valueOf(rate));
106 return parameters.build();