MediaCodec硬编码成H264视频流

android提供了一个强大的编解码类MediaCodec，可以实现对视频数据的编解码，下面讲一下如何对原始视频数据硬编码成h264格式的流

MediaCodec提供两种方式的输入，一种是将数据写入它的输入缓冲队列里，一种是让MediaCodec建立一个输入Surface，MediaCodec会自动从这个输入Surface中读取数据，因为我做的是录制屏幕的需求，所以我是使用一个Surface输入数据给MediaCodec。MediaCodec编码出来的头两帧是特殊的，分别是sps 和 pps这两帧在解码时要用来配置解码器用的。下面贴出编码器代码，这里我做的是视频实时编码传输，所以编码后的数据我使用socket发送的，大家主要还是看看编码部分的代码就好了：

package com.seewo.seewoair.coder; /** * @author zhangsutao * @file VideoCodec.java * @brief 视频编解码器基类 * @date 2016/8/7 */ public interface VideoCodec { String MIME_TYPE = "video/avc"; int VIDEO_FRAME_PER_SECOND = 15; int VIDEO_I_FRAME_INTERVAL = 5; int VIDEO_BITRATE = 500 * 8 * 1000; }

/** * @author zhangsutao * @file VideoEncoder.java * @brief 视频编码器 * @date 2016/7/29 */ public class VideoEncoder implements VideoCodec { private Worker mWorker; private MediaProjection mMediaProjection; private VirtualDisplay mVirtualDisplay; private Client mClient; //写入本地的流，在调试的时候使用 private DataOutputStream mOutput; private final boolean isDebug=true; private final String TAG="VideoEncoder"; private byte[] mFrameByte; public VideoEncoder(MediaProjection mediaProjection,Client client) { mClient=client; mMediaProjection=mediaProjection; if(isDebug){ try { mOutput=new DataOutputStream(new FileOutputStream(new File("/sdcard/h264encode")));; } catch (FileNotFoundException e) { e.printStackTrace(); } } } protected void onSurfaceCreated(Surface surface, int mWidth, int mHeight) { //将屏幕数据与surface进行关联 mVirtualDisplay = mMediaProjection.createVirtualDisplay("-display", mWidth, mHeight, 1, DisplayManager.VIRTUAL_DISPLAY_FLAG_PUBLIC, surface, null, null); } protected void onSurfaceDestroyed(Surface surface) { mVirtualDisplay.release(); surface.release(); } 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; } if(mClient!=null){ if(!mClient.hasRelease()){ mClient.release(); } } } private class Worker extends Thread { private MediaCodec.BufferInfo mBufferInfo; private MediaCodec mCodec; private volatile boolean isRunning; private Surface mSurface; private final long mTimeoutUsec; private int mWidth; private int mHeight; public Worker() { mBufferInfo = new MediaCodec.BufferInfo(); mTimeoutUsec = 10000l; } public void setRunning(boolean running) { isRunning = running; } protected void onEncodedSample(MediaCodec.BufferInfo info, ByteBuffer data) { if(mFrameByte==null||mFrameByte.length<info.size){ mFrameByte=new byte[info.size]; } data.get(mFrameByte,0,info.size); boolean isSuccess1=mClient.sendInt(info.size); boolean isSuccess2=mClient.send(mFrameByte,0,info.size); Log.d(TAG,"sending success:"+isSuccess1+" "+isSuccess2); if(!(isSuccess1&&isSuccess2)){ isRunning=false; mClient.release(); } //在debug时在本地写一份 if(isDebug){ try { mOutput.writeInt(info.size); mOutput.write(mFrameByte,0,info.size); } catch (IOException e) { e.printStackTrace(); } } } @Override public void run() { if(!prepare()){ isRunning=false; } while (isRunning) { encode(); } release(); } void encode() { if (!isRunning) { //编码结束，发送结束信号，让surface不在提供数据 mCodec.signalEndOfInputStream(); } int status = mCodec.dequeueOutputBuffer(mBufferInfo, mTimeoutUsec); if (status == MediaCodec.INFO_TRY_AGAIN_LATER) { return; } else if (status >= 0) { ByteBuffer data = mCodec.getOutputBuffer(status); if (data != null) { final int endOfStream = mBufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM; //传递编码数据 if (endOfStream == 0) { onEncodedSample(mBufferInfo, data); } // 一定要记得释放 mCodec.releaseOutputBuffer(status, false); if (endOfStream == MediaCodec.BUFFER_FLAG_END_OF_STREAM){ return; } } } } private void release() { onSurfaceDestroyed(mSurface); if(mCodec!=null){ mCodec.stop(); mCodec.release(); } if(mOutput!=null){ try { mOutput.close(); } catch (IOException e) { e.printStackTrace(); } } } private boolean prepare() { // configure video output mWidth= SpUtils.readInt(Constans.KEY_DEVICE_WIDTH,-1); mHeight=SpUtils.readInt(Constans.KEY_DEVICE_HEIGHT,-1); if(mWidth==-1||mHeight==-1){ return false; } mClient.connectToServer(); //发送宽高 boolean isSuccess1=mClient.sendInt(mWidth); boolean isSuccess2=mClient.sendInt(mHeight); if(!(isSuccess1&&isSuccess2)){ isRunning=false; mClient.release(); } MediaFormat format = MediaFormat.createVideoFormat(MIME_TYPE, mWidth, mHeight); format.setInteger(MediaFormat.KEY_COLOR_FORMAT, MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface); format.setInteger(MediaFormat.KEY_BIT_RATE, VIDEO_BITRATE); format.setInteger(MediaFormat.KEY_FRAME_RATE, VIDEO_FRAME_PER_SECOND); format.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL,VIDEO_I_FRAME_INTERVAL); format.setInteger(MediaFormat.KEY_REPEAT_PREVIOUS_FRAME_AFTER,40); try { mCodec = MediaCodec.createEncoderByType(MIME_TYPE); } catch (IOException e) { e.printStackTrace(); return false; } mCodec.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE); //创建关联的输入surface mSurface = mCodec.createInputSurface(); mCodec.start(); onSurfaceCreated(mSurface,mWidth,mHeight); return true; } } }