【Android 多媒体应用】使用MediaCodec将摄像头采集的视频编码为h264

MainActivity.java

import android.app.Activity;
import android.graphics.ImageFormat;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.hardware.Camera.PreviewCallback;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

import java.io.IOException;
import java.util.concurrent.ArrayBlockingQueue;

public class MainActivity extends Activity  implements SurfaceHolder.Callback,PreviewCallback{

    private SurfaceView surfaceview;

    private SurfaceHolder surfaceHolder;

    private Camera camera;

    private Parameters parameters;

    int width = 1280;

    int height = 720;

    int framerate = 30;

    int biterate = 8500*1000;

    private static int yuvqueuesize = 10;

    //待解码视频缓冲队列，静态成员！
    public static ArrayBlockingQueue<byte[]> YUVQueue = new ArrayBlockingQueue<byte[]>(yuvqueuesize);

    private AvcEncoder avcCodec;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        surfaceview = (SurfaceView)findViewById(R.id.surfaceview);
        surfaceHolder = surfaceview.getHolder();
        surfaceHolder.addCallback(this);
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        camera = getBackCamera();
        startcamera(camera);
        //创建AvEncoder对象
        avcCodec = new AvcEncoder(width,height,framerate,biterate);
        //启动编码线程
        avcCodec.StartEncoderThread();

    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        if (null != camera) {
            camera.setPreviewCallback(null);
            camera.stopPreview();
            camera.release();
            camera = null;
            avcCodec.StopThread();
        }
    }

    @Override
    public void onPreviewFrame(byte[] data, android.hardware.Camera camera) {
        //将当前帧图像保存在队列中
        putYUVData(data,data.length);
    }

    public void putYUVData(byte[] buffer, int length) {
        if (YUVQueue.size() >= 10) {
            YUVQueue.poll();
        }
        YUVQueue.add(buffer);
    }

    private void startcamera(Camera mCamera){
        if(mCamera != null){
            try {
                mCamera.setPreviewCallback(this);
                mCamera.setDisplayOrientation(90);
                if(parameters == null){
                    parameters = mCamera.getParameters();
                }
                //获取默认的camera配置
                parameters = mCamera.getParameters();
                //设置预览格式
                parameters.setPreviewFormat(ImageFormat.NV21);
                //设置预览图像分辨率
                parameters.setPreviewSize(width, height);
                //配置camera参数
                mCamera.setParameters(parameters);
                //将完全初始化的SurfaceHolder传入到setPreviewDisplay(SurfaceHolder)中
                //没有surface的话，相机不会开启preview预览
                mCamera.setPreviewDisplay(surfaceHolder);
                //调用startPreview()用以更新preview的surface，必须要在拍照之前start Preview
                mCamera.startPreview();

            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private Camera getBackCamera() {
        Camera c = null;
        try {
            //获取Camera的实例
            c = Camera.open(0);
        } catch (Exception e) {
            e.printStackTrace();
        }
        //获取Camera的实例失败时返回null
        return c;
    }

}

2.AvcEncoder.java

import android.media.MediaCodec;
import android.media.MediaCodecInfo;
import android.media.MediaFormat;
import android.os.Environment;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;

import static android.media.MediaCodec.BUFFER_FLAG_CODEC_CONFIG;
import static android.media.MediaCodec.BUFFER_FLAG_KEY_FRAME;

public class AvcEncoder
{
    private final static String TAG = "MeidaCodec";

    private int TIMEOUT_USEC = 12000;

    private MediaCodec mediaCodec;
    int m_width;
    int m_height;
    int m_framerate;

    public byte[] configbyte;

    public AvcEncoder(int width, int height, int framerate, int bitrate) {

        m_width  = width;
        m_height = height;
        m_framerate = framerate;
        MediaFormat mediaFormat = MediaFormat.createVideoFormat("video/avc", width, height);
        mediaFormat.setInteger(MediaFormat.KEY_COLOR_FORMAT, MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420SemiPlanar);
        mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, width*height*5);
        mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, 30);
        mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 1);
        try {
            mediaCodec = MediaCodec.createEncoderByType("video/avc");
        } catch (IOException e) {
            e.printStackTrace();
        }
        //配置编码器参数
        mediaCodec.configure(mediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
        //启动编码器
        mediaCodec.start();
        //创建保存编码后数据的文件
        createfile();
    }

    private static String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/test1.h264";
    private BufferedOutputStream outputStream;

    private void createfile(){
        File file = new File(path);
        if(file.exists()){
            file.delete();
        }
        try {
            outputStream = new BufferedOutputStream(new FileOutputStream(file));
        } catch (Exception e){
            e.printStackTrace();
        }
    }

    private void StopEncoder() {
        try {
            mediaCodec.stop();
            mediaCodec.release();
        } catch (Exception e){
            e.printStackTrace();
        }
    }

    public boolean isRuning = false;

    public void StopThread(){
        isRuning = false;
        try {
            StopEncoder();
            outputStream.flush();
            outputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    int count = 0;

    public void StartEncoderThread(){
        Thread EncoderThread = new Thread(new Runnable() {

            @Override
            public void run() {
                isRuning = true;
                byte[] input = null;
                long pts =  0;
                long generateIndex = 0;

                while (isRuning) {
                    //访问MainActivity用来缓冲待解码数据的队列
                    if (MainActivity.YUVQueue.size() >0){
                        //从缓冲队列中取出一帧
                        input = MainActivity.YUVQueue.poll();
                        byte[] yuv420sp = new byte[m_width*m_height*3/2];
                        //把待编码的视频帧转换为YUV420格式
                        NV21ToNV12(input,yuv420sp,m_width,m_height);
                        input = yuv420sp;
                    }
                    if (input != null) {
                        try {
                            long startMs = System.currentTimeMillis();
                            //编码器输入缓冲区
                            ByteBuffer[] inputBuffers = mediaCodec.getInputBuffers();
                            //编码器输出缓冲区
                            ByteBuffer[] outputBuffers = mediaCodec.getOutputBuffers();
                            int inputBufferIndex = mediaCodec.dequeueInputBuffer(-1);
                            if (inputBufferIndex >= 0) {
                                pts = computePresentationTime(generateIndex);
                                ByteBuffer inputBuffer = inputBuffers[inputBufferIndex];
                                inputBuffer.clear();
                                //把转换后的YUV420格式的视频帧放到编码器输入缓冲区中
                                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 == BUFFER_FLAG_CODEC_CONFIG){
                                    configbyte = new byte[bufferInfo.size];
                                    configbyte = outData;
                                }else if(bufferInfo.flags == BUFFER_FLAG_KEY_FRAME){
                                    byte[] keyframe = new byte[bufferInfo.size + configbyte.length];
                                    System.arraycopy(configbyte, 0, keyframe, 0, configbyte.length);
                                    //把编码后的视频帧从编码器输出缓冲区中拷贝出来
                                    System.arraycopy(outData, 0, keyframe, configbyte.length, outData.length);

                                    outputStream.write(keyframe, 0, keyframe.length);
                                }else{
                                    //写到文件中
                                    outputStream.write(outData, 0, 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();

    }

    private void NV21ToNV12(byte[] nv21,byte[] nv12,int width,int height){
        if(nv21 == null || nv12 == null)return;
        int framesize = width*height;
        int i = 0,j = 0;
        System.arraycopy(nv21, 0, nv12, 0, framesize);
        for(i = 0; i < framesize; i++){
            nv12[i] = nv21[i];
        }
        for (j = 0; j < framesize/2; j+=2)
        {
            nv12[framesize + j-1] = nv21[j+framesize];
        }
        for (j = 0; j < framesize/2; j+=2)
        {
            nv12[framesize + j] = nv21[j+framesize-1];
        }
    }

    /**
     * Generates the presentation time for frame N, in microseconds.
     */
    private long computePresentationTime(long frameIndex) {
        return 132 + frameIndex * 1000000 / m_framerate;
    }
}

3.activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <SurfaceView
        android:id="@+id/surfaceview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</RelativeLayout>

4.添加权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.INTERNET" />