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概述

    在Android开发中，使用OpenGL ES来渲染视频是一种常见的需求，尤其是在需要实现自定义的视频播放界面或者视频特效时。结合MediaPlayer，我们可以实现一个功能强大的视频播放器。以下是一个简单的示例，展示如何在Android应用中使用OpenGL ES和MediaPlayer播放本地视频。
    常规的视频播放方式有VideoView, MediaPlayer + SurfaceView / TextureView, 以TextureView为例, 它与OpenGL(GLSurfaceView)播放的一些比较:

TextureView的优缺点

• 优点：
  • 灵活性高：TextureView可以与其他View叠加使用，非常适合在复杂的视图层次结构中使用。
  • 硬件加速支持：由于它在硬件加速层进行渲染，其性能也较优。
  • 支持绘制操作：可以从其他线程更新内容，适合用于播放视频、显示实时特效等。
• 缺点：
  • 内存占用较高：TextureView的内部缓冲队列导致比SurfaceView使用更多的内存。
  • 在5.0以前在主线程渲染：在5.0版本之前，TextureView在主线程渲染，可能会导致性能问题。

OpenGL的优缺点

• 优点：
  • 高度定制化：OpenGL提供低级别的图形渲染接口，允许开发者高度定制视频播放界面和特效。
  • 性能优化：通过优化渲染代码，可以在一定程度上提高视频播放的效率和性能。
• 缺点：
  • 开发复杂度较高：使用OpenGL需要编写大量的底层代码，包括顶点着色器和片段着色器的编写，这增加了开发的复杂度和难度。

    TextureView在灵活性、硬件加速支持和多线程更新方面具有优势，适合需要与其他视图交互的场景。而OpenGL则提供了更高的定制化程度，适合需要实现复杂图形效果的场景

实现

    梳理收集来的参考代码, 实现视频播放效果如下:

GLVideoActivity.java

package com.ansondroider.sdktester.activity;import android.media.MediaPlayer;
import android.opengl.GLSurfaceView;
import android.os.Bundle;import com.ansondroider.acore.BaseActivity;
import com.ansondroider.sdktester.gl.GLVideoView;import java.io.IOException;public class GLVideoActivity extends BaseActivity {MediaPlayer mmp;GLVideoView glView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);glView = new GLVideoView(this);setContentView(glView);}@Overrideprotected void onStart() {super.onStart();//postDelayed(new Runnable() {//    @Override//    public void run() {mmp = new MediaPlayer();try {mmp.setDataSource("/sdcard/Movies/376463.mp4");mmp.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {@Overridepublic void onPrepared(MediaPlayer mediaPlayer) {glView.onVideoPrepared(mediaPlayer);}});mmp.prepare();} catch (IOException e) {e.printStackTrace();}//    }//}, 100);}@Overrideprotected void onStop() {super.onStop();mmp.stop();mmp.release();}
}

GLVideoView.java

package com.ansondroider.sdktester.gl;
import android.content.Context;
import android.graphics.SurfaceTexture;
import android.media.MediaPlayer;
import android.opengl.GLES11Ext;
import android.opengl.GLES20;
import android.opengl.GLSurfaceView;
import android.opengl.Matrix;
import android.util.AttributeSet;
import android.util.Log;
import android.view.Surface;import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
/*** @ProjectName: TheSimpllestplayer* @Package: com.yw.thesimpllestplayer.renderview* @ClassName: VideoDrawer* @Description: 视频渲染器* @Author: wei.yang* @CreateDate: 2021/11/6 14:23* @UpdateUser: 更新者：wei.yang* @UpdateDate: 2021/11/6 14:23* @UpdateRemark: 更新说明：* @Version: 1.0*/
public class GLVideoView extends GLSurfaceView {final String TAG = "GLVideoView";//顶点坐标，此处的坐标系是物体坐标系：中心店坐标是（0,0）private float[] mVertexCoors = new float[]{-1f, -1f,1f, -1f,-1f, 1f,1f, 1f};//纹理坐标系，中心坐标点为（0.5,0.5），上方向为t从0~1，右边方向为s，从0~1.刚好和计算器物理坐标系是反过来的。private float[] mTextureCoors = new float[]{0f, 1f,1f, 1f,0f, 0f,1f, 0f};private String vertextShaderSource = "attribute vec4 aPosition;" +"precision mediump float;" +"uniform mat4 uMatrix;" +"attribute vec2 aCoordinate;" +"varying vec2 vCoordinate;" +"attribute float alpha;" +"varying float inAlpha;" +"void main(){" +"gl_Position = uMatrix*aPosition;" +"vCoordinate = aCoordinate;" +"inAlpha = alpha;" +"}";private String fragmentShaderSource = "#extension GL_OES_EGL_image_external : require\n" +"precision mediump float;" +"varying vec2 vCoordinate;" +"varying float inAlpha;" +"uniform samplerExternalOES uTexture;" +"void main() {" +"vec4 color = texture2D(uTexture, vCoordinate);" +"gl_FragColor = vec4(color.r, color.g, color.b, inAlpha);" +"}";//视频宽高private int mVideoWidth = -1;private int mVideoHeight = -1;//物理屏幕的宽高private int mWorldWidth = -1;private int mWorldHeight = -1;//纹理IDprivate int mTextureId = -1;//定义SurfaceTexture 为显示视频做准备;private SurfaceTexture mSurfaceTexture = null;// 定义OpenGL 程序IDprivate int mProgram = -1;//矩阵变换接受者（shader中）private int mVertexMatrixHandler = -1;//顶点坐标接收者private int mVertexPosHandler = -1;//纹理坐标接受者private int mTexturePosHandler = -1;//纹理接受者private int mTextureHandler = -1;//半透明值接受者private int mAlphaHandler = -1;//顶点缓冲private FloatBuffer mVertexBuffer = null;//纹理缓冲private FloatBuffer mTextureBuffer = null;//矩阵private float[] mMatrix = null;//透明度private float mAlpha = 1f;//旋转角度private float mWidthRatio = 1f;private float mHeightRatio = 1f;private int floatLength = 16;public GLVideoView(Context context) {super(context);init();}public GLVideoView(Context context, AttributeSet attrs) {super(context, attrs);init();}private void init(){setEGLContextClientVersion(2);setRenderer(new VideoRender());setRenderMode(RENDERMODE_WHEN_DIRTY);initPos();}/*** 初始化顶点坐标*/private void initPos() {ByteBuffer vByteBuffer = ByteBuffer.allocateDirect(mVertexCoors.length * 4);vByteBuffer.order(ByteOrder.nativeOrder());//将坐标转换为floatbuffer，用以传给opengl程序mVertexBuffer = vByteBuffer.asFloatBuffer();mVertexBuffer.put(mVertexCoors);mVertexBuffer.position(0);ByteBuffer tByteBuffer = ByteBuffer.allocateDirect(mTextureCoors.length * 4);tByteBuffer.order(ByteOrder.nativeOrder());mTextureBuffer = tByteBuffer.asFloatBuffer();mTextureBuffer.put(mTextureCoors);mTextureBuffer.position(0);}/*** 初始化矩阵变换，主要是防止视频拉伸变形*/private void initDefMatrix() {//Log.d(TAG, "initDefMatrix");if (mMatrix != null) return;if (mVideoWidth != -1 && mVideoHeight != -1 &&mWorldWidth != -1 && mWorldHeight != -1) {mMatrix = new float[floatLength];float[] prjMatrix = new float[floatLength];float originRatio = mVideoWidth / (float) mVideoHeight;float worldRatio = mWorldWidth / (float) mWorldHeight;if (mWorldWidth > mWorldHeight) {if (originRatio > worldRatio) {mHeightRatio = originRatio / worldRatio;Matrix.orthoM(prjMatrix, 0,-mWidthRatio, mWidthRatio,-mHeightRatio, mHeightRatio,3f, 5f);} else {// 原始比例小于窗口比例，缩放高度度会导致高度超出，因此，高度以窗口为准，缩放宽度mWidthRatio = worldRatio / originRatio;Matrix.orthoM(prjMatrix, 0,-mWidthRatio, mWidthRatio,-mHeightRatio, mHeightRatio,3f, 5f);}} else {if (originRatio > worldRatio) {mHeightRatio = originRatio / worldRatio;Matrix.orthoM(prjMatrix, 0,-mWidthRatio, mWidthRatio,-mHeightRatio, mHeightRatio,3f, 5f);} else {// 原始比例小于窗口比例，缩放高度会导致高度超出，因此，高度以窗口为准，缩放宽度mWidthRatio = worldRatio / originRatio;Matrix.orthoM(prjMatrix, 0,-mWidthRatio, mWidthRatio,-mHeightRatio, mHeightRatio,3f, 5f);}}//设置相机位置float[] viewMatrix = new float[floatLength];Matrix.setLookAtM(viewMatrix, 0,0f, 0f, 5.0f,0f, 0f, 0f,0f, 1.0f, 0f);//计算变换矩阵Matrix.multiplyMM(mMatrix, 0, prjMatrix, 0, viewMatrix, 0);}}private Surface mSurface = null;MediaPlayer mMediaPlayer;public void onVideoPrepared(MediaPlayer mp){Log.d(TAG, "onVideoPrepared");mMediaPlayer = mp;if(mSurfaceTexture != null) {int videoWidth = mMediaPlayer.getVideoWidth();int videoHeight = mMediaPlayer.getVideoHeight();setVideoSize(videoWidth, videoHeight);mSurface = new Surface(mSurfaceTexture);mMediaPlayer.setSurface(mSurface);mMediaPlayer.start();}}private void setVideoSize(int videoWidth, int videoHeight) {Log.d(TAG, "setVideoSize " + videoWidth + "x" + videoHeight);mVideoWidth = videoWidth;mVideoHeight = videoHeight;}private void setWorldSize(int worldWidth, int worldHeight) {mWorldWidth = worldWidth;mWorldHeight = worldHeight;}@Overridepublic void setAlpha(float alpha) {super.setAlpha(alpha);mAlpha = alpha;}private SurfaceTexture getSurfaceTexture() {return mSurfaceTexture;}/*** 创建并使用opengles程序*/private void createGLPrg() {if (mProgram == -1) {int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertextShaderSource);int fragmentShader = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderSource);//创建programe陈谷mProgram = GLES20.glCreateProgram();//将顶点着色器加入程序GLES20.glAttachShader(mProgram, vertexShader);//将片元着色器加入程序GLES20.glAttachShader(mProgram, fragmentShader);GLES20.glLinkProgram(mProgram);//从程序中获取句柄mVertexMatrixHandler = GLES20.glGetUniformLocation(mProgram, "uMatrix");mVertexPosHandler = GLES20.glGetAttribLocation(mProgram, "aPosition");mTextureHandler = GLES20.glGetUniformLocation(mProgram, "uTexture");mTexturePosHandler = GLES20.glGetAttribLocation(mProgram, "aCoordinate");mAlphaHandler = GLES20.glGetAttribLocation(mProgram, "alpha");}//使用opengl程序GLES20.glUseProgram(mProgram);}/*** 激活并绑定纹理单元*/private void activateTexture() {//激活指定纹理单元GLES20.glActiveTexture(GLES20.GL_TEXTURE0);//绑定纹理ID到纹理单元GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextureId);//将激活并绑定的纹理id传递到着色器里面GLES20.glUniform1i(mTextureHandler, 0);//配置边缘过滤参数GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,GLES20.GL_TEXTURE_MIN_FILTER,GLES20.GL_LINEAR);GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,GLES20.GL_TEXTURE_MAG_FILTER,GLES20.GL_LINEAR);//配置s轴和t轴的方式GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,GLES20.GL_TEXTURE_WRAP_S,GLES20.GL_CLAMP_TO_EDGE);GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,GLES20.GL_TEXTURE_WRAP_T,GLES20.GL_CLAMP_TO_EDGE);}private void updateTexture() {mSurfaceTexture.updateTexImage();}/*** 加载着色器** @param shaderType 着色器类型* @param shaderCode 着色器代码* @return*/private int loadShader(int shaderType, String shaderCode) {//根据着色器类型创建着色器int shader = GLES20.glCreateShader(shaderType);//将着色其代码加入到着色器GLES20.glShaderSource(shader, shaderCode);//编译zhuoseqGLES20.glCompileShader(shader);return shader;}/*** 开始绘制渲染*/public void doDraw() {if(mMatrix == null)return;//启用顶点坐标句柄GLES20.glEnableVertexAttribArray(mVertexPosHandler);GLES20.glEnableVertexAttribArray(mTexturePosHandler);GLES20.glUniformMatrix4fv(mVertexMatrixHandler, 1, false, mMatrix, 0);//设置着色器参数， 第二个参数表示一个顶点包含的数据数量，这里为xy，所以为2GLES20.glVertexAttribPointer(mVertexPosHandler, 2, GLES20.GL_FLOAT, false, 0, mVertexBuffer);GLES20.glVertexAttribPointer(mTexturePosHandler,2,GLES20.GL_FLOAT,false,0,mTextureBuffer);GLES20.glVertexAttrib1f(mAlphaHandler, mAlpha);//开始绘制GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, mVertexCoors.length / 2);}@Overrideprotected void onDetachedFromWindow() {Log.d(TAG, "onDetachedFromWindow");super.onDetachedFromWindow();GLES20.glDisableVertexAttribArray(mVertexPosHandler);GLES20.glDisableVertexAttribArray(mTexturePosHandler);GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0);GLES20.glDeleteTextures(1, new int[]{mTextureId}, 0);GLES20.glDeleteProgram(mProgram);if(mMediaPlayer != null){//mMediaPlayer.setSurface(null);mMediaPlayer.release();mSurface.release();}}public void translate(float dx, float dy) {Matrix.translateM(mMatrix, 0, dx * mWidthRatio * 2, -dy * mHeightRatio * 2, 0f);}public void scale(float sx, float sy) {Matrix.scaleM(mMatrix, 0, sx, sy, 1f);mWidthRatio /= sx;mHeightRatio /= sy;}public class VideoRender implements GLSurfaceView.Renderer {@Overridepublic void onSurfaceCreated(GL10 gl, EGLConfig config) {Log.d(TAG, "onSurfaceCreated");GLES20.glClearColor(0f, 0f, 0f, 0f);//开启混合，即半透明GLES20.glEnable(GLES20.GL_BLEND);GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA);int[] textureIds = new int[1];GLES20.glGenTextures(1, textureIds, 0);mTextureId = textureIds[0];//根据textureId初始化一个SurfaceTexturemSurfaceTexture = new SurfaceTexture(mTextureId);mSurfaceTexture.setOnFrameAvailableListener(new SurfaceTexture.OnFrameAvailableListener() {@Overridepublic void onFrameAvailable(SurfaceTexture surfaceTexture) {requestRender();}});if(mMediaPlayer != null){onVideoPrepared(mMediaPlayer);}}@Overridepublic void onSurfaceChanged(GL10 gl, int width, int height) {Log.d(TAG, "onSurfaceChanged");GLES20.glViewport(0, 0, width, height);setWorldSize(width, height);}@Overridepublic void onDrawFrame(GL10 gl) {Log.d(TAG, "onDrawFrame");if(mMediaPlayer == null || !mMediaPlayer.isPlaying())return;//清除颜色缓冲和深度缓冲GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);if (mTextureId != -1) {initDefMatrix();//2/创建、编译、启动opengles着色器createGLPrg();//3.激活并绑定纹理单元activateTexture();//4.绑定图元到纹理单元updateTexture();//5.开始绘制渲染doDraw();}}}
}

复杂图形效果的场景

普通的视频播放方式很难实现 曲面 百叶窗 这类的效果, 如:

而使用OpenGL播放, 只需要调整下顶点和纹理的坐标即可:

    //顶点坐标，此处的坐标系是物体坐标系：中心店坐标是（0,0）private float[] mVertexCoors = new float[]{-1f, 1f,-1f, -1f,0, 0.5f,0, -0.5f,1f, 1f,1f, -1f,};//纹理坐标系，中心坐标点为（0.5,0.5），上方向为t从0~1，右边方向为s，从0~1.刚好和计算器物理坐标系是反过来的。private float[] mTextureCoors = new float[]{0f, 0f,0f, 1f,0.5f, 0,0.5f, 1f,1f, 0f,1f, 1f};

参考

1. 10.GLSurfaceView+MediaPlayer播放视频.md
2. 【Android 音视频开发打怪升级：OpenGL渲染视频画面篇】二、使用OpenGL渲染视频画面
3. Android 最简单的视频播放器之OpenGL ES视频渲染工具封装（三）