效果图
实现源码（已上传我的GitHub）：
https://github.com/xiaxveliang/GL_AUDIO_VIDEO_RECODE
参考：
http://bigflake.com/mediacodec/EncodeAndMuxTest.java.txt
对于以上代码，我做了一个简单的注释，代码如下：
import android.media.MediaCodec;
import android.media.MediaCodecInfo;
import android.media.MediaFormat;
import android.media.MediaMuxer;
import android.opengl.EGL14;
import android.opengl.EGLConfig;
import android.opengl.EGLContext;
import android.opengl.EGLDisplay;
import android.opengl.EGLExt;
import android.opengl.EGLSurface;
import android.opengl.GLES20;
import android.os.Environment;
import android.test.AndroidTestCase;
import android.util.Log;
import android.view.Surface;
import java.io.File;
import java.io.IOException;
import java.nio.ByteBuffer;
// wiki:
// http://bigflake.com/mediacodec/EncodeAndMuxTest.java.txt
public class EncodeAndMuxTest extends AndroidTestCase {
private static final String TAG = EncodeAndMuxTest.class.getSimpleName();
// 输出文件路径
private static final File MY_OUTPUT_DIR = Environment.getExternalStorageDirectory();
// H.264编码
private static final String MY_MIME_TYPE = "video/avc";
// 视频文件的宽高
private static final int MY_VIDEO_WIDTH = 480;
private static final int MY_VIDEO_HEIGHT = 480;
// 视频码率
private static final int MY_BIT_RATE = 800000;
// 每秒钟15帧
private static final int MY_FPS = 15;
// 总共30帧,每一秒15帧,所以30帧为2秒钟
private static final int NUM_FRAMES = 30;
// RGB color values for generated frames
private static final int TEST_R0 = 0;
private static final int TEST_G0 = 136;
private static final int TEST_B0 = 0;
//
private static final int TEST_R1 = 236;
private static final int TEST_G1 = 50;
private static final int TEST_B1 = 186;
// encoder / muxer state
private MediaCodec mEncoder;
// H.264 转 mp4
private MediaMuxer mMuxer;
private CodecInputSurface mInputSurface;
private int mTrackIndex;
private boolean mMuxerStarted;
// allocate one of these up front so we don't need to do it every time
private MediaCodec.BufferInfo mBufferInfo;
/**
* opengl绘制一个buffer，转成MP4,程序入口
*/
public void testEncodeVideoToMp4() {
try {
// 初始化Encoder
initVideoEncoder();
// 设置 EGLDisplay dpy, EGLSurface draw, EGLSurface read, EGLContext ctx
mInputSurface.makeCurrent();
// 共30帧
for (int i = 0; i < NUM_FRAMES; i++) {
// mEncoder从缓冲区取数据，然后交给mMuxer编码
drainEncoder(false);
// opengl绘制一帧
generateSurfaceFrame(i);
// 设置图像，发送给EGL的显示时间
mInputSurface.setPresentationTime(computePresentationTimeNsec(i));
// Submit it to the encoder
mInputSurface.swapBuffers();
}
// send end-of-stream to encoder, and drain remaining output
drainEncoder(true);
} finally {
// release encoder, muxer, and input Surface
releaseEncoder();
}
}
/**
* 初始化视频编码器
*/
private void initVideoEncoder() {
// 创建一个buffer
mBufferInfo = new MediaCodec.BufferInfo();
//-----------------MediaFormat-----------------------
// mediaCodeC采用的是H.264编码
MediaFormat format = MediaFormat.createVideoFormat(MY_MIME_TYPE, MY_VIDEO_WIDTH, MY_VIDEO_HEIGHT);
// 数据来源自surface
format.setInteger(MediaFormat.KEY_COLOR_FORMAT,
MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface);
// 视频码率
format.setInteger(MediaFormat.KEY_BIT_RATE, MY_BIT_RATE);
// fps
format.setInteger(MediaFormat.KEY_FRAME_RATE, MY_FPS);
//设置关键帧的时间
format.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 10);
//-----------------Encoder-----------------------
try {
mEncoder = MediaCodec.createEncoderByType(MY_MIME_TYPE);
mEncoder.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
// 创建一个surface
Surface surface = mEncoder.createInputSurface();
// 创建一个CodecInputSurface,其中包含GL相关
mInputSurface = new CodecInputSurface(surface);
//
mEncoder.start();
} catch (Exception e) {
e.printStackTrace();
}
//-----------------输出文件路径-----------------------
// 输出文件路径
String outputPath = new File(MY_OUTPUT_DIR,
"test." + MY_VIDEO_WIDTH + "x" + MY_VIDEO_HEIGHT + ".mp4").toString();
//-----------------MediaMuxer-----------------------
try {
// 输出为MP4
mMuxer = new MediaMuxer(outputPath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
} catch (IOException ioe) {
throw new RuntimeException("MediaMuxer creation failed", ioe);
}
mTrackIndex = -1;
mMuxerStarted = false;
}
/**
* Releases encoder resources. May be called after partial / failed initialization.
* 释放资源
*/
private void releaseEncoder() {
if (mEncoder != null) {
mEncoder.stop();
mEncoder.release();
mEncoder = null;
}
if (mInputSurface != null) {
mInputSurface.release();
mInputSurface = null;
}
if (mMuxer != null) {
mMuxer.stop();
mMuxer.release();
mMuxer = null;
}
}
/**
* mEncoder从缓冲区取数据，然后交给mMuxer编码
*
* @param endOfStream 是否停止录制
*/
private void drainEncoder(boolean endOfStream) {
final int TIMEOUT_USEC = 10000;
// 停止录制
if (endOfStream) {
mEncoder.signalEndOfInputStream();
}
//拿到输出缓冲区,用于取到编码后的数据
ByteBuffer[] encoderOutputBuffers = mEncoder.getOutputBuffers();
while (true) {
//拿到输出缓冲区的索引
int encoderStatus = mEncoder.dequeueOutputBuffer(mBufferInfo, TIMEOUT_USEC);
if (encoderStatus == MediaCodec.INFO_TRY_AGAIN_LATER) {
// no output available yet
if (!endOfStream) {
break; // out of while
} else {
}
} else if (encoderStatus == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
//拿到输出缓冲区,用于取到编码后的数据
encoderOutputBuffers = mEncoder.getOutputBuffers();
} else if (encoderStatus == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
// should happen before receiving buffers, and should only happen once
if (mMuxerStarted) {
throw new RuntimeException("format changed twice");
}
//
MediaFormat newFormat = mEncoder.getOutputFormat();
// now that we have the Magic Goodies, start the muxer
mTrackIndex = mMuxer.addTrack(newFormat);
//
mMuxer.start();
mMuxerStarted = true;
} else if (encoderStatus < 0) {
} else {
//获取解码后的数据
ByteBuffer encodedData = encoderOutputBuffers[encoderStatus];
if (encodedData == null) {
throw new RuntimeException("encoderOutputBuffer " + encoderStatus +
" was null");
}
//
if ((mBufferInfo.flags & MediaCodec.BUFFER_FLAG_CODEC_CONFIG) != 0) {
mBufferInfo.size = 0;
}
//
if (mBufferInfo.size != 0) {
if (!mMuxerStarted) {
throw new RuntimeException("muxer hasn't started");
}
// adjust the ByteBuffer values to match BufferInfo (not needed?)
encodedData.position(mBufferInfo.offset);
encodedData.limit(mBufferInfo.offset + mBufferInfo.size);
// 编码
mMuxer.writeSampleData(mTrackIndex, encodedData, mBufferInfo);
}
//释放资源
mEncoder.releaseOutputBuffer(encoderStatus, false);
if ((mBufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
if (!endOfStream) {
Log.w(TAG, "reached end of stream unexpectedly");
} else {
}
break; // out of while
}
}
}
}
/**
* Generates a frame of data using GL commands. We have an 8-frame animation
* sequence that wraps around. It looks like this:
* <pre>
* 0 1 2 3
* 7 6 5 4
* </pre>
* We draw one of the eight rectangles and leave the rest set to the clear color.
*/
private void generateSurfaceFrame(int frameIndex) {
frameIndex %= 8;
int startX, startY;
if (frameIndex < 4) {
// (0,0) is bottom-left in GL
startX = frameIndex * (MY_VIDEO_WIDTH / 4);
startY = MY_VIDEO_HEIGHT / 2;
} else {
startX = (7 - frameIndex) * (MY_VIDEO_WIDTH / 4);
startY = 0;
}
GLES20.glClearColor(TEST_R0 / 255.0f, TEST_G0 / 255.0f, TEST_B0 / 255.0f, 1.0f);
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
GLES20.glEnable(GLES20.GL_SCISSOR_TEST);
GLES20.glScissor(startX, startY, MY_VIDEO_WIDTH / 4, MY_VIDEO_HEIGHT / 2);
GLES20.glClearColor(TEST_R1 / 255.0f, TEST_G1 / 255.0f, TEST_B1 / 255.0f, 1.0f);
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
GLES20.glDisable(GLES20.GL_SCISSOR_TEST);
}
/**
* Generates the presentation time for frame N, in nanoseconds.
* 好像是生成当前帧的时间,具体怎么计算的,不懂呀??????????????????????????
*/
private static long computePresentationTimeNsec(int frameIndex) {
final long ONE_BILLION = 1000000000;
return frameIndex * ONE_BILLION / MY_FPS;
}
/**
* Holds state associated with a Surface used for MediaCodec encoder input.
* <p>
* The constructor takes a Surface obtained from MediaCodec.createInputSurface(), and uses that
* to create an EGL window surface. Calls to eglSwapBuffers() cause a frame of data to be sent
* to the video encoder.
* <p>
* This object owns the Surface -- releasing this will release the Surface too.
*/
private static class CodecInputSurface {
private static final int EGL_RECORDABLE_ANDROID = 0x3142;
private EGLDisplay mEGLDisplay = EGL14.EGL_NO_DISPLAY;
private EGLContext mEGLContext = EGL14.EGL_NO_CONTEXT;
private EGLSurface mEGLSurface = EGL14.EGL_NO_SURFACE;
private Surface mSurface;
/**
* Creates a CodecInputSurface from a Surface.
*/
public CodecInputSurface(Surface surface) {
if (surface == null) {
throw new NullPointerException();
}
mSurface = surface;
initEGL();
}
/**
* 初始化EGL
*/
private void initEGL() {
//--------------------mEGLDisplay-----------------------
// 获取EGL Display
mEGLDisplay = EGL14.eglGetDisplay(EGL14.EGL_DEFAULT_DISPLAY);
// 错误检查
if (mEGLDisplay == EGL14.EGL_NO_DISPLAY) {
throw new RuntimeException("unable to get EGL14 display");
}
// 初始化
int[] version = new int[2];
if (!EGL14.eglInitialize(mEGLDisplay, version, 0, version, 1)) {
throw new RuntimeException("unable to initialize EGL14");
}
// Configure EGL for recording and OpenGL ES 2.0.
int[] attribList = {
EGL14.EGL_RED_SIZE, 8,
EGL14.EGL_GREEN_SIZE, 8,
EGL14.EGL_BLUE_SIZE, 8,
EGL14.EGL_ALPHA_SIZE, 8,
//
EGL14.EGL_RENDERABLE_TYPE,
EGL14.EGL_OPENGL_ES2_BIT,
// 录制android
EGL_RECORDABLE_ANDROID,
1,
EGL14.EGL_NONE
};
EGLConfig[] configs = new EGLConfig[1];
int[] numConfigs = new int[1];
// eglCreateContext RGB888+recordable ES2
EGL14.eglChooseConfig(mEGLDisplay, attribList, 0, configs, 0, configs.length, numConfigs, 0);
// Configure context for OpenGL ES 2.0.
int[] attrib_list = {
EGL14.EGL_CONTEXT_CLIENT_VERSION, 2,
EGL14.EGL_NONE
};
//--------------------mEGLContext-----------------------
// eglCreateContext
mEGLContext = EGL14.eglCreateContext(mEGLDisplay, configs[0], EGL14.EGL_NO_CONTEXT,
attrib_list, 0);
checkEglError("eglCreateContext");
//--------------------mEGLSurface-----------------------
// 创建一个WindowSurface并与surface进行绑定,这里的surface来自mEncoder.createInputSurface();
// Create a window surface, and attach it to the Surface we received.
int[] surfaceAttribs = {
EGL14.EGL_NONE
};
// eglCreateWindowSurface
mEGLSurface = EGL14.eglCreateWindowSurface(mEGLDisplay, configs[0], mSurface,
surfaceAttribs, 0);
checkEglError("eglCreateWindowSurface");
}
/**
* Discards all resources held by this class, notably the EGL context. Also releases the
* Surface that was passed to our constructor.
* 释放资源
*/
public void release() {
if (mEGLDisplay != EGL14.EGL_NO_DISPLAY) {
EGL14.eglMakeCurrent(mEGLDisplay, EGL14.EGL_NO_SURFACE, EGL14.EGL_NO_SURFACE,
EGL14.EGL_NO_CONTEXT);
EGL14.eglDestroySurface(mEGLDisplay, mEGLSurface);
EGL14.eglDestroyContext(mEGLDisplay, mEGLContext);
EGL14.eglReleaseThread();
EGL14.eglTerminate(mEGLDisplay);
}
mSurface.release();
mEGLDisplay = EGL14.EGL_NO_DISPLAY;
mEGLContext = EGL14.EGL_NO_CONTEXT;
mEGLSurface = EGL14.EGL_NO_SURFACE;
mSurface = null;
}
/**
* Makes our EGL context and surface current.
* 设置 EGLDisplay dpy, EGLSurface draw, EGLSurface read, EGLContext ctx
*/
public void makeCurrent() {
EGL14.eglMakeCurrent(mEGLDisplay, mEGLSurface, mEGLSurface, mEGLContext);
checkEglError("eglMakeCurrent");
}
/**
* Calls eglSwapBuffers. Use this to "publish" the current frame.
* 用该方法，发送当前Frame
*/
public boolean swapBuffers() {
boolean result = EGL14.eglSwapBuffers(mEGLDisplay, mEGLSurface);
checkEglError("eglSwapBuffers");
return result;
}
/**
* Sends the presentation time stamp to EGL. Time is expressed in nanoseconds.
* 设置图像，发送给EGL的时间间隔
*/
public void setPresentationTime(long nsecs) {
// 设置发动给EGL的时间间隔
EGLExt.eglPresentationTimeANDROID(mEGLDisplay, mEGLSurface, nsecs);
checkEglError("eglPresentationTimeANDROID");
}
/**
* Checks for EGL errors. Throws an exception if one is found.
* 检查错误,代码可以忽略
*/
private void checkEglError(String msg) {
int error;
if ((error = EGL14.eglGetError()) != EGL14.EGL_SUCCESS) {
throw new RuntimeException(msg + ": EGL error: 0x" + Integer.toHexString(error));
}
}
}
}