AudioTrack播放acc格式音頻

AudioTrack本身只支持播放pcm格式音頻，想要使用AudioTrack播放acc格式音頻，還需要其他api來進行數據封裝。

MediaExtractor

MediaCodec

package com.zero.demo;

/**
* Created by yingkun_che on 19-6-19.
* 使用AudioTrack 播放acc音頻測試
*/
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;
import android.media.MediaCodec;
import android.media.MediaCodec.BufferInfo;
import android.media.MediaExtractor;
import android.media.MediaFormat;
import android.util.Log;
import java.io.IOException;
import java.nio.ByteBuffer;


public class AudioDecoderThread {
    private static final int TIMEOUT_US = 1000;
    private MediaExtractor mExtractor;
    private MediaCodec mDecoder;


    private boolean eosReceived;
    private int mSampleRate = 0;


    private final String TAG = "AACPlay";
    String accPath="/storage/emulated/0/Android/data/com.zero.demo/files/zero_editor_kuato/resources/themes/satura/Stratosphere.aac";
    public void startPlay(String path) throws IOException {
        eosReceived = false;
        //創建MediaExtractor對象用來解AAC封裝
        mExtractor = new MediaExtractor();
        try {
            //設置需要MediaExtractor解析的文件的路徑
            mExtractor.setDataSource(path);
        } catch (IOException e) {
            e.printStackTrace();
        }

        MediaFormat format = mExtractor.getTrackFormat(0);
        if (format == null)
        {
            Log.e(TAG,"format is null");
            return;
        }

        //判斷當前幀的文件類型是否爲audio
        String mime = format.getString(MediaFormat.KEY_MIME);
        if (mime.startsWith("audio/")) {
            Log.d(TAG, "format : " + format);
            //獲取當前幀的採樣率
            mExtractor.selectTrack(0);
            mSampleRate = format.getInteger(MediaFormat.KEY_SAMPLE_RATE);
            //獲取當前幀的通道數
            int channel  = format.getInteger(MediaFormat.KEY_CHANNEL_COUNT);
            //音頻文件長度
            long duration = format.getLong(MediaFormat.KEY_DURATION);
            Log.d(TAG,"length:"+duration/1000000);
        }

        //創建MediaCodec對象
        mDecoder = MediaCodec.createDecoderByType(mime);
        //配置MediaCodec
        mDecoder.configure(format, null, null, 0);

        if (mDecoder == null) {
            Log.e(TAG, "Can't find video info!");
            return;
        }
        //啓動MediaCodec
        mDecoder.start();
        new Thread(AACDecoderAndPlayRunnable).start();
    }

    Runnable AACDecoderAndPlayRunnable = new Runnable() {
        @Override
        public void run() {
            AACDecoderAndPlay();
        }
    };

    private void AACDecoderAndPlay() {
        ByteBuffer[] inputBuffers = mDecoder.getInputBuffers();
        ByteBuffer[] outputBuffers = mDecoder.getOutputBuffers();

        BufferInfo info = new BufferInfo();

        int buffsize = AudioTrack.getMinBufferSize(mSampleRate, AudioFormat.CHANNEL_OUT_STEREO, AudioFormat.ENCODING_PCM_16BIT);
        // 創建AudioTrack對象
        AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, mSampleRate,
                AudioFormat.CHANNEL_OUT_STEREO,
                AudioFormat.ENCODING_PCM_16BIT,
                buffsize,
                AudioTrack.MODE_STREAM);
        //啓動AudioTrack
        audioTrack.play();
    int num=0;
        while (!eosReceived) {
            int inIndex = mDecoder.dequeueInputBuffer(TIMEOUT_US);
            if (inIndex >= 0) {
                ByteBuffer buffer = inputBuffers[inIndex];
                //從MediaExtractor中讀取一幀待解數據
                int sampleSize = mExtractor.readSampleData(buffer, 0);
                if (sampleSize < 0) {
                    // We shouldn't stop the playback at this point, just pass the EOS
                    // flag to mDecoder, we will get it again from the
                    // dequeueOutputBuffer
                    Log.d(TAG, "InputBuffer BUFFER_FLAG_END_OF_STREAM");
                    mDecoder.queueInputBuffer(inIndex, 0, 0, 0, MediaCodec.BUFFER_FLAG_END_OF_STREAM);


                } else {
                    //向MediaDecoder輸入一幀待解碼數據
                    mDecoder.queueInputBuffer(inIndex, 0, sampleSize, mExtractor.getSampleTime(), 0);
                    mExtractor.advance();
                }
                //從MediaDecoder隊列取出一幀解碼後的數據
                int outIndex = mDecoder.dequeueOutputBuffer(info, TIMEOUT_US);
                if (info.size>0){
                    Log.d(TAG, "INFO_OUTPUT_BUFFERS_CHANGED num: "+num);
                    num=0;
                }else{
                    num++;
                }
                switch (outIndex) {
                    case MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED:
                        Log.d(TAG, "INFO_OUTPUT_BUFFERS_CHANGED");
                        outputBuffers = mDecoder.getOutputBuffers();
                        break;
                    case MediaCodec.INFO_OUTPUT_FORMAT_CHANGED:
                        MediaFormat format = mDecoder.getOutputFormat();
                        Log.d(TAG, "New format " + format);
                        audioTrack.setPlaybackRate(format.getInteger(MediaFormat.KEY_SAMPLE_RATE));
                        break;
                    case MediaCodec.INFO_TRY_AGAIN_LATER:
                        Log.d(TAG, "dequeueOutputBuffer timed out!");
                        break;
                    default:
                        ByteBuffer outBuffer = outputBuffers[outIndex];
                        //Log.v(TAG, "outBuffer: " + outBuffer);

                        final byte[] chunk = new byte[info.size];
                        // Read the buffer all at once
                        outBuffer.get(chunk);
                        //清空buffer,否則下一次得到的還會得到同樣的buffer
                        outBuffer.clear();
                        // AudioTrack write data
                        audioTrack.write(chunk, info.offset, info.offset + info.size);
                        mDecoder.releaseOutputBuffer(outIndex, false);//這一行必須加,因爲在P上mDecoder.dequeueOutputBuffer 前面會有80次沒有數據,需要釋放緩衝區,否則無聲音
                        break;
                }
                // 所有幀都解碼、播放完之後退出循環
                if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
                    Log.d(TAG, "OutputBuffer BUFFER_FLAG_END_OF_STREAM");
                    break;
                }
            }
        }
        //釋放MediaDecoder資源
        mDecoder.stop();
        mDecoder.release();
        mDecoder = null;

        //釋放MediaExtractor資源
        mExtractor.release();
        mExtractor = null;

        //釋放AudioTrack資源
        audioTrack.stop();
        audioTrack.release();
        audioTrack = null;
    }

    public void stop() {
        eosReceived = true;
    }
}