Android音视频开发图解

概述Android音视频开发学习路线，具备这些知识摄像头相关配置参数实时获取摄像头原始数据NV21原始数据编码 *** 作的线程，编码h.264格式数据publicvoidstartEncoderThread(){ThreadEncoderThread=newThread(newRunnable(){@SuppressLint("NewApi

AndroID音视频开发学习路线，具备这些知识

摄像头相关配置参数

实时获取摄像头原始数据

NV21原始数据编码 *** 作的线程，编码h.264格式数据

public voID startEncoderThread(){        Thread EncoderThread = new Thread(new Runnable() {            @Suppresslint("NewAPI")            @OverrIDe            public voID run() {                isRuning = true;                byte[] input = null;                long pts =  0;                long generateIndex = 0;                while (isRuning) {                    if (CameraSurfaceVIEw.YUVQueue.size() >0){                        input = CameraSurfaceVIEw.YUVQueue.poll();                        byte[] yuv420sp = new byte[m_wIDth*m_height*3/2];                        byte[] yuv420 = new byte[m_wIDth*m_height*3/2];                        VIDeoYUVUtil.NV21ToNV12(input,yuv420sp,m_wIDth,m_height);//                        VIDeoYUVUtil.YUV420spRotate90Clockwise(yuv420sp,yuv420,m_wIDth,m_height);                        input = yuv420sp;                    }                    if (input != null) {                        try {                            long startMs = System.currentTimeMillis();                            ByteBuffer[] inputBuffers = mediaCodec.getinputBuffers();                            ByteBuffer[] outputBuffers = mediaCodec.getoutputBuffers();                            int inputBufferIndex = mediaCodec.dequeueinputBuffer(-1);                            if (inputBufferIndex >= 0) {                                pts = computePresentationTime(generateIndex);                                ByteBuffer inputBuffer = inputBuffers[inputBufferIndex];                                inputBuffer.clear();                                inputBuffer.put(input);                                mediaCodec.queueinputBuffer(inputBufferIndex, 0, input.length, pts, 0);                                generateIndex += 1;                            }                            MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();                            int outputBufferIndex = mediaCodec.dequeueOutputBuffer(bufferInfo, TIMEOUT_USEC);                            while (outputBufferIndex >= 0) {                                //Log.i("AvcEncoder", "Get H264 Buffer Success! flag = "+bufferInfo.flags+",pts = "+bufferInfo.presentationTimeUs+"");                                ByteBuffer outputBuffer = outputBuffers[outputBufferIndex];                                byte[] outData = new byte[bufferInfo.size];                                outputBuffer.get(outData);                                if(bufferInfo.flags == 2){                                    configbyte = new byte[bufferInfo.size];                                    configbyte = outData;                                }else if(bufferInfo.flags == 1){                                    byte[] keyframe = new byte[bufferInfo.size + configbyte.length];                                    System.arraycopy(configbyte, 0, keyframe, 0, configbyte.length);                                    System.arraycopy(outData, 0, keyframe, configbyte.length, outData.length);                                    outputStream.write(keyframe, 0, keyframe.length);                                    if(onEncoderVIDeoListener!=null){                                        onEncoderVIDeoListener.encoderVIDeoData(keyframe,keyframe.length);                                    }                                }else{                                    outputStream.write(outData, 0, outData.length);                                    if(onEncoderVIDeoListener!=null){                                        onEncoderVIDeoListener.encoderVIDeoData(outData,outData.length);                                    }                                }                                mediaCodec.releaSEOutputBuffer(outputBufferIndex, false);                                outputBufferIndex = mediaCodec.dequeueOutputBuffer(bufferInfo, TIMEOUT_USEC);                            }                        } catch (Throwable t) {                            t.printstacktrace();                        }                    } else {                        try {                            Thread.sleep(500);                        } catch (InterruptedException e) {                            e.printstacktrace();                        }                    }                }            }        });        EncoderThread.start();    }

实时采集原始PCM音频数据的线程

原始PCM数据编码AAC音频数据

 /**     * 编码AAC音频线程     */    public voID startAudioEncodeAAC() {        audioEncoderThread = new Thread() {            @OverrIDe            public voID run() {                try {                 while (!audioEncoderLoop && !Thread.interrupted()) {                    AudioData audioData = audioQueue.take();                    byte[] buffer = audioData.audioData;                if(audioData != null && encoder != null)                {                    int size = audioData.audioData.length;                    //录音时间  size/ 采样率*声道数 * bits/8                    recordTime += size * 1.0 / (audioSamplerate * 2 * (16 / 8));//                    LogUtils.d("recordTime = " + recordTime);                    int inputBufferindex = encoder.dequeueinputBuffer(0);                    if(inputBufferindex >= 0)                    {                        ByteBuffer byteBuffer = encoder.getinputBuffers()[inputBufferindex];                        byteBuffer.clear();                        byteBuffer.put(buffer);                        encoder.queueinputBuffer(inputBufferindex, 0, size, 0, 0);                    }                    int index = encoder.dequeueOutputBuffer(info, 0);                    while(index >= 0)                    {                        try {                            perpCMSize = info.size + 7;                            outByteBuffer = new byte[perpCMSize];                            ByteBuffer byteBuffer = encoder.getoutputBuffers()[index];                            byteBuffer.position(info.offset);                            byteBuffer.limit(info.offset + info.size);                            addADtsheader(outByteBuffer, perpCMSize, aacsamplerate);                            byteBuffer.get(outByteBuffer, 7, info.size);                            byteBuffer.position(info.offset);                            if (audioEncderListener!=null){                                audioEncderListener.encoderAudioData(outByteBuffer,perpCMSize);                            }                            encoder.releaSEOutputBuffer(index, false);                            index = encoder.dequeueOutputBuffer(info, 0);                            outByteBuffer = null;                        } catch (Exception e) {                            e.printstacktrace();                        }                    }                }}                } catch (InterruptedException e) {                    e.printstacktrace();                }            }        };        audioEncoderThread.start();    }

编码好的h.264视频数据和AAC音频数据经过封包成数据包通过网络协议(rtmp)实时发送数据。

将接收到的视频h.264数据解码成原始数据并播放。

送入解码线程进行解码 *** 作

H.264实时解码成原始数据并进行渲染画面

接收到的AAC音频数据送入解码音频的线程进行解码还原成原始PCM音频数据

/** * aac解码+播放 */public voID decode(byte[] buf, int offset, int length) {    //输入ByteBuffer    ByteBuffer[] codecinputBuffers = mDecoder.getinputBuffers();    //输出ByteBuffer    ByteBuffer[] codecOutputBuffers = mDecoder.getoutputBuffers();    //等待时间，0->不等待，-1->一直等待    long kTimeOutUs = 0;    try {        //返回一个包含有效数据的input buffer的index,-1->不存在        int inputBufIndex = mDecoder.dequeueinputBuffer(kTimeOutUs);        if (inputBufIndex >= 0) {            //获取当前的ByteBuffer            ByteBuffer dstBuf = codecinputBuffers[inputBufIndex];            //清空ByteBuffer            dstBuf.clear();            //填充数据            dstBuf.put(buf, offset, length);            //将指定index的input buffer提交给解码器            mDecoder.queueinputBuffer(inputBufIndex, 0, length, 0, 0);        }        //编解码器缓冲区        MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();        //返回一个output buffer的index，-1->不存在        int outputBufferIndex = mDecoder.dequeueOutputBuffer(info, kTimeOutUs);        if (outputBufferIndex < 0) {            //记录解码失败的次数            count++;        }        ByteBuffer outputBuffer;        while (outputBufferIndex >= 0) {            //获取解码后的ByteBuffer            outputBuffer = codecOutputBuffers[outputBufferIndex];            //用来保存解码后的数据            byte[] outData = new byte[info.size];            outputBuffer.get(outData);            //清空缓存            outputBuffer.clear();            //播放解码后的数据            mPlayer.playAudioTrack(outData, 0, info.size);            //释放已经解码的buffer            mDecoder.releaSEOutputBuffer(outputBufferIndex, false);            //解码未解完的数据            outputBufferIndex = mDecoder.dequeueOutputBuffer(info, kTimeOutUs);        }    } catch (Exception e) {        e.printstacktrace();    }

将解码后的PCM送入AudioTrack进行播放，这个时候就有声音了。

 

因为音频和视频解码是分开的，所以在解码后，需要做音视频同步。通常有一些音视频同步算法。如在ffmepg中，以音频作为参考时钟，视频用于比较当前时钟和音频时钟的差值，如果快了，就要增大延迟，以便下一帧显示的晚一些；如果慢了，就要减少延迟，加快显示下一帧。

感谢各位关注。

 

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