AudioTrackDecoder.java revision 8ca55fc980a567270d397c7392fd5fa8490f6d42 
1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package androidx.media.filterfw.decoder;
18
19import android.annotation.TargetApi;
20import android.media.MediaCodec;
21import android.media.MediaCodec.BufferInfo;
22import android.media.MediaFormat;
23
24import androidx.media.filterfw.FrameValue;
25
26import java.io.ByteArrayOutputStream;
27import java.io.IOException;
28import java.nio.ByteBuffer;
29
30/**
31 * {@link TrackDecoder} for decoding audio tracks.
32 *
33 * TODO: find out if we always get 16 bits per channel and document.
34 */
35@TargetApi(16)
36public class AudioTrackDecoder extends TrackDecoder {
37
38    private final ByteArrayOutputStream mAudioByteStream; // Guarded by mAudioByteStreamLock.
39    private final Object mAudioByteStreamLock;
40
41    private int mAudioSampleRate;
42    private int mAudioChannelCount;
43    private long mAudioPresentationTimeUs;
44
45    public AudioTrackDecoder(int trackIndex, MediaFormat format, Listener listener) {
46        super(trackIndex, format, listener);
47
48        if (!DecoderUtil.isAudioFormat(format)) {
49            throw new IllegalArgumentException(
50                    "AudioTrackDecoder can only be used with audio formats");
51        }
52
53        mAudioByteStream = new ByteArrayOutputStream();
54        mAudioByteStreamLock = new Object();
55
56        mAudioSampleRate = format.getInteger(MediaFormat.KEY_SAMPLE_RATE);
57        mAudioChannelCount = format.getInteger(MediaFormat.KEY_CHANNEL_COUNT);
58    }
59
60    @Override
61    protected MediaCodec initMediaCodec(MediaFormat format) {
62        MediaCodec mediaCodec = MediaCodec.createDecoderByType(
63                format.getString(MediaFormat.KEY_MIME));
64        mediaCodec.configure(format, null, null, 0);
65        return mediaCodec;
66    }
67
68    @Override
69    protected boolean onDataAvailable(
70            MediaCodec codec, ByteBuffer[] buffers, int bufferIndex, BufferInfo info) {
71        ByteBuffer buffer = buffers[bufferIndex];
72        byte[] data = new byte[info.size];
73        buffer.position(info.offset);
74        buffer.get(data, 0, info.size);
75
76        synchronized (mAudioByteStreamLock) {
77            try {
78                if (mAudioByteStream.size() == 0 && data.length > 0) {
79                    mAudioPresentationTimeUs = info.presentationTimeUs;
80                }
81
82                mAudioByteStream.write(data);
83            } catch (IOException e) {
84                // Just drop the audio sample.
85            }
86        }
87
88        buffer.clear();
89        codec.releaseOutputBuffer(bufferIndex, false);
90        notifyListener();
91        return true;
92    }
93
94    /**
95     * Fills the argument {@link FrameValue} with an audio sample containing the audio that was
96     * decoded since the last call of this method. The decoder's buffer is cleared as a result.
97     */
98    public void grabSample(FrameValue audioFrame) {
99        synchronized (mAudioByteStreamLock) {
100            if (audioFrame != null) {
101                AudioSample sample = new AudioSample(
102                        mAudioSampleRate, mAudioChannelCount, mAudioByteStream.toByteArray());
103                audioFrame.setValue(sample);
104                audioFrame.setTimestamp(mAudioPresentationTimeUs * 1000);
105            }
106            clearBuffer();
107        }
108    }
109
110    /**
111     * Clears the decoder's buffer.
112     */
113    public void clearBuffer() {
114        synchronized (mAudioByteStreamLock) {
115            mAudioByteStream.reset();
116        }
117    }
118
119}
120