Android MediaCodec解码aac,播放.

来源：互联网发布：mac jdk tar.gz 安装编辑：程序博客网时间：2024/05/17 07:00

自己写了个小测试：
对本地的aac文件用MediaCodec解码出来，就是pcm编码的音频数据了，然后直接将pcm数据写进AudioTrack进行播放。

public class AudioDecoder {    private static final String TAG = "AudioDecoder";    public static final int KEY_CHANNEL_COUNT = 0;    private Worker mWorker;    private String path;//aac文件的路径。    public AudioDecoder(String filename) {        this.path = filename;    }    public void start() {        if (mWorker == null) {            mWorker = new Worker();            mWorker.setRunning(true);            mWorker.start();        }    }    public void stop() {        if (mWorker != null) {            mWorker.setRunning(false);            mWorker = null;        }    }    private class Worker extends Thread {        private static final int KEY_SAMPLE_RATE = 0;        private boolean isRunning = false;        private AudioTrack mPlayer;        private MediaCodec mDecoder;        private MediaExtractor extractor;        public void setRunning(boolean run) {            isRunning = run;        }        @Override        public void run() {            super.run();            if (!prepare()) {                isRunning = false;                Log.d(TAG, "音频解码器初始化失败");            }            while (isRunning) {                decode();            }            release();        }        /**         * 等待客户端连接，初始化解码器         *          * @return 初始化失败返回false，成功返回true         */        public boolean prepare() {            // 等待客户端            mPlayer = new AudioTrack(AudioManager.STREAM_MUSIC, 8000, AudioFormat.CHANNEL_OUT_STEREO,                    AudioFormat.ENCODING_PCM_16BIT, 2048, AudioTrack.MODE_STREAM);//            mPlayer.play();            try {                mDecoder = MediaCodec.createDecoderByType("audio/mp4a-latm");                final String encodeFile = path;                extractor = new MediaExtractor();                extractor.setDataSource(encodeFile);                MediaFormat mediaFormat = null;                for (int i = 0; i < extractor.getTrackCount(); i++) {                    MediaFormat format = extractor.getTrackFormat(i);                    String mime = format.getString(MediaFormat.KEY_MIME);                    if (mime.startsWith("audio/")) {                        extractor.selectTrack(i);                        mediaFormat = format;                        break;                    }                }                mediaFormat.setString(MediaFormat.KEY_MIME, "audio/mp4a-latm");                mediaFormat.setInteger(MediaFormat.KEY_CHANNEL_COUNT, KEY_CHANNEL_COUNT);                mediaFormat.setInteger(MediaFormat.KEY_SAMPLE_RATE, KEY_SAMPLE_RATE);                mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, 24000);                mediaFormat.setInteger(MediaFormat.KEY_IS_ADTS, 1);                mediaFormat.setInteger(MediaFormat.KEY_AAC_PROFILE, 0);                mDecoder.configure(mediaFormat, null, null, 0);            } catch (IOException e) {                e.printStackTrace();                return false;            }            if (mDecoder == null) {                Log.e(TAG, "create mediaDecode failed");                return false;            }            mDecoder.start();            return true;        }        /**         * aac解码+播放         */        public void decode() {            ByteBuffer[] codecInputBuffers = mDecoder.getInputBuffers();            ByteBuffer[] codecOutputBuffers = mDecoder.getOutputBuffers();            final long kTimeOutUs = 5000;            MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();            boolean sawInputEOS = false;            boolean sawOutputEOS = false;            int totalRawSize = 0;            try {                while (!sawOutputEOS) {                    if (!sawInputEOS) {                        int inputBufIndex = mDecoder.dequeueInputBuffer(kTimeOutUs);                        if (inputBufIndex >= 0) {                            ByteBuffer dstBuf = codecInputBuffers[inputBufIndex];                            int sampleSize = extractor.readSampleData(dstBuf, 0);                            if (sampleSize < 0) {                                Log.i("TAG", "saw input EOS.");                                sawInputEOS = true;                                mDecoder.queueInputBuffer(inputBufIndex, 0, 0, 0, MediaCodec.BUFFER_FLAG_END_OF_STREAM);                            } else {                                long presentationTimeUs = extractor.getSampleTime();                                mDecoder.queueInputBuffer(inputBufIndex, 0, sampleSize, presentationTimeUs, 0);                                extractor.advance();                            }                        }                    }                    int res = mDecoder.dequeueOutputBuffer(info, kTimeOutUs);                    if (res >= 0) {                        int outputBufIndex = res;                        // Simply ignore codec config buffers.                        if ((info.flags & MediaCodec.BUFFER_FLAG_CODEC_CONFIG) != 0) {                            Log.i("TAG", "audio encoder: codec config buffer");                            mDecoder.releaseOutputBuffer(outputBufIndex, false);                            continue;                        }                        if (info.size != 0) {                            ByteBuffer outBuf = codecOutputBuffers[outputBufIndex];                            outBuf.position(info.offset);                            outBuf.limit(info.offset + info.size);                            byte[] data = new byte[info.size];                            outBuf.get(data);                            totalRawSize += data.length;                            // fosDecoder.write(data);                            // 播放音乐                            mPlayer.write(data, 0, info.size);                        }                        mDecoder.releaseOutputBuffer(outputBufIndex, false);                        if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {                            Log.i("TAG", "saw output EOS.");                            sawOutputEOS = true;                        }                    } else if (res == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {                        codecOutputBuffers = mDecoder.getOutputBuffers();                        Log.i("TAG", "output buffers have changed.");                    } else if (res == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {                        MediaFormat oformat = mDecoder.getOutputFormat();                        Log.i("TAG", "output format has changed to " + oformat);                    }                }            } finally {                // fosDecoder.close();                extractor.release();            }        }        /**         * 释放资源         */        private void release() {            if (mDecoder != null) {                mDecoder.stop();                mDecoder.release();            }            if (mPlayer != null) {                mPlayer.stop();                mPlayer.release();                mPlayer = null;            }            if (extractor != null) {                extractor.release();                extractor = null;            }        }    }}

使用的时候就传aac文件的路径，然后直接开启线程就可以了：

    String fielPath = (Environment.getExternalStorageDirectory().getPath() + "/audio.aac");        AudioDecoder audioDecoder = new AudioDecoder(fielPath);        audioDecoder.start();

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