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

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;
}}

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;
}
}

<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>

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