[RK3288][Android6.0] 一个例子看MediaCodec使用流程
Platform: Rockchip
OS: Android 6.0
Kernel: 3.10.92
目录
-
- 编码过程
- 主要步骤
- 例子源代码
- 主代码部分
- 编码部分
- 参考
一个使用MediaCodec的例子，正好可以从例子看编码的过程，可以借鉴参考。
编码过程：
从Camera preview callback里拿数据 -> 数据格式转换 -> 编码输入 -> 处理 -> 编码输出
主要步骤：
以下是例子使用MeidaCodec的主要步骤，我把它摘出来了，详细部分见后面源代码。
mediaCodec = MediaCodec.createEncoderByType("video/avc");
编码类型是avc
MediaFormat mediaFormat = MediaFormat.createVideoFormat("video/avc", width,height);
根据宽高创建MediaFormat,设置参数需要MediaFormat.
mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, bitrate);
mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, framerate);
mediaFormat.setInteger(MediaFormat.KEY_COLOR_FORMAT,
MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420Planar);
mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 1);
根据当前需求设置参数
mediaCodec.configure(mediaFormat, null, null,
MediaCodec.CONFIGURE_FLAG_ENCODE);
参数2表示编码后输出到哪个surface，这里编码直接输出到buffer，所以可以为NULL。
参数4设置MediaCodec.CONFIGURE_FLAG_ENCODE表示配置成编码器。
mediaCodec.start();
开始运行
avcCodec.offerEncoder(arg0,h264);
Camera preview callback拿到数据arg0后送到编码器，编码完成后输出到h264缓存里。
swapYV12toI420(input, yuv420, m_width, m_height);
由于camera输出的数据格式和编码器支持的输入数据格式不一致，需要先转换。
mediaCodec.getInputBuffers(); inputBufferIndex =
mediaCodec.dequeueInputBuffer(-1); ByteBuffer inputBuffer =
inputBuffers[inputBufferIndex];
获取输入空闲buffer，然后得到空闲buffer中的一个index，这样就可以得到要使用的buffer了
inputBuffer.put(yuv420);
mediaCodec.queueInputBuffer(inputBufferIndex, 0, input.length, 0,
0);
输入入队准备后就开始编码处理了
ByteBuffer[] outputBuffers = mediaCodec.getOutputBuffers();
outputBufferIndex = mediaCodec.dequeueOutputBuffer(bufferInfo,0);
outputBuffer = outputBuffers[outputBufferIndex];
同样的方式，编码处理完成取出编码后的数据buffer
mediaCodec.releaseOutputBuffer(outputBufferIndex, false);
当前buffer用好了就释放掉给下一轮编码使用
FileOut.write(output,0,pos);
编码后的数据可以做拿去解码，网络发送等，这里就写到文件保存下来。
例子源代码：
主代码部分：
package com.example.com.rk.dec_enc;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.graphics.ImageFormat;
import android.hardware.Camera;
import android.hardware.Camera.PreviewCallback;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;
import android.view.View;
@SuppressLint("NewApi") public class MainActivity extends Activity implements PreviewCallback {
AvcEncoder avcCodec = null;
AvcDecoder avcDecodec = null;
boolean avcDecFlag = false;
boolean avcEncFlag = false;
//boolean RecordCameraFrameDataFlag = true;
boolean RecordCameraFrameDataFlag = false;
public Camera m_camera;
SurfaceView m_prevewview;
SurfaceHolder m_surfaceHolder;
SurfaceView mDecSurfaceView;
SurfaceHolder mDecSurfaceHolder;
MediaPlayer mMediaPlayer;
private SurfaceHolder.Callback mSurfaceCallback;
int width = 1280;
int height = 720;
int framerate = 30;
int bitrate = 500000;
FileOutputStream FileOut = null;
byte[] h264 = new byte[width*height*3/2];
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
m_prevewview = (SurfaceView) findViewById(R.id.SurfaceViewPlay);
mDecSurfaceView = (SurfaceView) findViewById(R.id.SurfaceViewPlay_Dec);
mSurfaceCallback = new SurfaceHolder.Callback(){
@Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2,
int arg3) {
// TODO Auto-generated method stub
}
@Override
public void surfaceCreated(SurfaceHolder arg0) {
// TODO Auto-generated method stub
Log.d("Hery", "arg0 =" + arg0);
mDecSurfaceHolder = mDecSurfaceView.getHolder(); // Bind SurfaceView. get SurfaceHolder context
m_surfaceHolder = m_prevewview.getHolder(); // Bind SurfaceView get SurfaceHolder context
mDecSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
m_surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
boolean m_surfaceHolderisCreat = m_surfaceHolder.isCreating();
Log.d("Hery", "m_surfaceHolder =" + m_surfaceHolderisCreat);
boolean mmDecSurfaceHolderisCreat = mDecSurfaceHolder.isCreating();
Log.d("Hery", "mmDecSurfaceHolderisCreat =" + mmDecSurfaceHolderisCreat);
if(mmDecSurfaceHolderisCreat == true && (avcDecodec== null) && (avcDecFlag == false))
{
Log.d("Hery", "Create AvcDecoder");
avcDecodec = new AvcDecoder(width,height,mDecSurfaceHolder);
avcDecFlag = true;
}
if(m_surfaceHolderisCreat == true && (avcCodec == null) && (avcEncFlag == false))
{
Log.d("Hery", "Create Camera");
avcCodec = new AvcEncoder(width,height,framerate,bitrate);
avcEncFlag = true;
m_camera = Camera.open();
try {
m_camera.setPreviewDisplay(m_surfaceHolder);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Camera.Parameters parameters = m_camera.getParameters();
parameters.setPreviewSize(width, height);
parameters.setPictureSize(width, height);
parameters.setPreviewFormat(ImageFormat.YV12);
m_camera.setParameters(parameters);
m_camera.setPreviewCallback((PreviewCallback)MainActivity.this);
m_camera.startPreview();
}
}
@Override
public void surfaceDestroyed(SurfaceHolder arg0) {
// TODO Auto-generated method stub
Log.d("Hery","surfaceDestroyed");
}
};
mDecSurfaceView.getHolder().addCallback(mSurfaceCallback);
m_prevewview.getHolder().addCallback(mSurfaceCallback);
m_prevewview.setVisibility(View.VISIBLE);
mDecSurfaceView.setVisibility(View.VISIBLE);
if(RecordCameraFrameDataFlag)
{
try {
FileOut = new FileOutputStream(new File("/sdcard/app_camera.yuv"));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public void onPreviewFrame(byte[] arg0, Camera arg1) {
//Log.d("Hery", "onPreviewFrame");
if(RecordCameraFrameDataFlag)
{
try {
FileOut.write(arg0,0,arg0.length);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// TODO Auto-generated method stub
int size = avcCodec.offerEncoder(arg0,h264);
avcDecodec.pushData(h264,size);
}
}编码部分：
package com.example.com.rk.dec_enc;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import android.annotation.SuppressLint;
import android.media.MediaCodec;
import android.media.MediaCodecInfo;
import android.media.MediaFormat;
import android.util.Log;
@SuppressLint("NewApi") public class AvcEncoder {
private MediaCodec mediaCodec;
int m_width;
int m_height;
//boolean RecordEncDataFlag = true;
boolean RecordEncDataFlag = false;
byte[] m_info = null;
FileOutputStream FileOut = null;
private byte[] yuv420 = null;
public AvcEncoder(int width, int height, int framerate, int bitrate) {
Log.d("Hery", "AvcEncoder IN");
m_width = width;
m_height = height;
yuv420 = new byte[width*height*3/2];
mediaCodec = MediaCodec.createEncoderByType("video/avc");
MediaFormat mediaFormat = MediaFormat.createVideoFormat("video/avc", width, height);
mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, bitrate);
mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, framerate);
mediaFormat.setInteger(MediaFormat.KEY_COLOR_FORMAT, MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420Planar);
mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 1);
mediaCodec.configure(mediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
mediaCodec.start();
if(RecordEncDataFlag)
{
try {
FileOut = new FileOutputStream(new File("/sdcard/app_camera_enc.h264"));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public void close() {
try {
mediaCodec.stop();
mediaCodec.release();
} catch (Exception e){
e.printStackTrace();
}
try {
FileOut.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public int offerEncoder(byte[] input, byte[] output)
{
//Log.d("......................................................Hery", "Encoder in");
int pos = 0;
swapYV12toI420(input, yuv420, m_width, m_height);
try {
ByteBuffer[] inputBuffers = mediaCodec.getInputBuffers();
ByteBuffer[] outputBuffers = mediaCodec.getOutputBuffers();
int inputBufferIndex = mediaCodec.dequeueInputBuffer(-1);
//Log.d("......................................................Hery", "inputBufferIndex = " +inputBufferIndex);
if (inputBufferIndex >= 0)
{
ByteBuffer inputBuffer = inputBuffers[inputBufferIndex];
inputBuffer.clear();
inputBuffer.put(yuv420);
mediaCodec.queueInputBuffer(inputBufferIndex, 0, input.length, 0, 0);
}
MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
int outputBufferIndex = mediaCodec.dequeueOutputBuffer(bufferInfo,0);
//Log.d("......................................................Hery", "outputBufferIndex = " +outputBufferIndex);
while (outputBufferIndex >= 0)
{
ByteBuffer outputBuffer = outputBuffers[outputBufferIndex];
byte[] outData = new byte[bufferInfo.size];
outputBuffer.get(outData);
if(m_info != null)
{
System.arraycopy(outData, 0, output, pos, outData.length);
pos += outData.length;
}
else
{
ByteBuffer spsPpsBuffer = ByteBuffer.wrap(outData);
if (spsPpsBuffer.getInt() == 0x00000001)
{
m_info = new byte[outData.length];
System.arraycopy(outData, 0, m_info, 0, outData.length);
System.arraycopy(outData, 0, output, pos, outData.length);
pos+=outData.length;
}
else
{
return -1;
}
}
mediaCodec.releaseOutputBuffer(outputBufferIndex, false);
outputBufferIndex = mediaCodec.dequeueOutputBuffer(bufferInfo, 0);
}
if(output[4] == 0x65) //key frame
{
System.arraycopy(output, 0, yuv420, 0, pos);
System.arraycopy(m_info, 0, output, 0, m_info.length);
System.arraycopy(yuv420, 0, output, m_info.length, pos);
pos += m_info.length;
}
} catch (Throwable t) {
t.printStackTrace();
}
//Log.d("......................................................Hery", "Encoder out");
if(RecordEncDataFlag)
{
try {
FileOut.write(output,0,pos);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return pos;
}
private void swapYV12toI420(byte[] yv12bytes, byte[] i420bytes, int width, int height)
{
System.arraycopy(yv12bytes, 0, i420bytes, 0,width*height);
System.arraycopy(yv12bytes, width*height+width*height/4, i420bytes, width*height,width*height/4);
System.arraycopy(yv12bytes, width*height, i420bytes, width*height+width*height/4,width*height/4);
}
}
参考：
Android中直播视频技术探究之—基础知识大纲介绍