opengl es 中MediaCodec通过C++将YUV格式编码成MP4视频代码例子

以下是一个简单的例子，展示了如何使用OpenGL ES和MediaCodec将YUV格式编码成MP4视频。在此之前，需要确保您已经了解了OpenGL ES和MediaCodec的基本使用方法。

首先，需要创建OpenGL ES环境，并将YUV数据绘制到纹理上。以下是示例代码：

// 创建OpenGL ES环境
EGLDisplay eglDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
EGLint major, minor;
eglInitialize(eglDisplay, &major, &minor);

EGLint configAttribs[] = {
    EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
    EGL_BLUE_SIZE, 8,
    EGL_GREEN_SIZE, 8,
    EGL_RED_SIZE, 8,
    EGL_DEPTH_SIZE, 0,
    EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
    EGL_NONE
};

EGLint numConfigs;
EGLConfig eglConfig;
eglChooseConfig(eglDisplay, configAttribs, &eglConfig, 1, &numConfigs);

EGLint pbufferAttribs[] = {
    EGL_WIDTH, width,
    EGL_HEIGHT, height,
    EGL_NONE,
};

EGLSurface eglSurface = eglCreatePbufferSurface(eglDisplay, eglConfig, pbufferAttribs);
eglMakeCurrent(eglDisplay, eglSurface, eglSurface, eglContext);

// 创建OpenGL ES纹理
GLuint textureID;
glGenTextures(1, &textureID);
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

// 绘制YUV数据到纹理上
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width, height, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, YUVData);
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE_ALPHA, width / 2, height / 2, 0, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, YUVData + width * height);
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE_ALPHA, width / 2, height / 2, 0, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, YUVData + width * height * 5 / 4);

然后，需要创建MediaCodec编码器，并将OpenGL ES纹理作为输入数据。以下是示例代码：

// 创建MediaCodec编码器
AMediaFormat* format = AMediaFormat_new();
AMediaFormat_setString(format, AMEDIAFORMAT_KEY_MIME, "video/avc");
AMediaFormat_setInt32(format, AMEDIAFORMAT_KEY_WIDTH, width);
AMediaFormat_setInt32(format, AMEDIAFORMAT_KEY_HEIGHT, height);
AMediaFormat_setInt32(format, AMEDIAFORMAT_KEY_BIT_RATE, bitRate);
AMediaFormat_setInt32(format, AMEDIAFORMAT_KEY_FRAME_RATE, frameRate);
AMediaFormat_setInt32(format, AMEDIAFORMAT_KEY_COLOR_FORMAT, OMX_COLOR_FormatYUV420SemiPlanar);
AMediaFormat_setInt32(format, AMEDIAFORMAT_KEY_I_FRAME_INTERVAL, iFrameInterval);

AMediaCodec* codec = AMediaCodec_createEncoderByType("video/avc");
AMediaCodec_configure(codec, format, NULL, NULL, AMEDIACODEC_CONFIGURE_FLAG_ENCODE);
AMediaCodec_start(codec);

// 将OpenGL ES纹理作为输入数据
AMediaCodecBufferInfo bufferInfo;
memset(&bufferInfo, 0, sizeof(bufferInfo));

glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);

for (int i = 0; i < frameCount; i++) {
    GLuint textureID;
    glGenTextures(1, &textureID);
    glBindTexture(GL_TEXTURE_2D, textureID);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);

    // 绘制YUV数据到纹理上
    glBindTexture(GL_TEXTURE_2D, textureID);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width, height, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, YUVData);
    glBindTexture(GL_TEXTURE_2D, textureID);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE_ALPHA, width / 2, height / 2, 0, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, YUVData + width * height);
    glBindTexture(GL_TEXTURE_2D, textureID);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE_ALPHA, width / 2, height / 2, 0, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, YUVData + width * height * 5 / 4);

    // 将纹理作为输入数据
    glUseProgram(program);
    glUniform1i(texSamplerHandle, 0);
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, textureID);

    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

    // 从MediaCodec编码器获取输出数据
    int outputBufferIndex = AMediaCodec_dequeueOutputBuffer(codec, &bufferInfo, 0);
    if (outputBufferIndex >= 0) {
        AMediaCodecBufferInfo* outputBufferInfo = AMediaCodec_getOutputBufferInfo(codec, outputBufferIndex);
        uint8_t* outputBuffer = AMediaCodec_getOutputBuffer(codec, outputBufferIndex);

        // 将输出数据写入MP4文件
        fwrite(outputBuffer, 1, outputBufferInfo->size, outputFile);

        AMediaCodec_releaseOutputBuffer(codec, outputBufferIndex, false);
    }
}

最后，需要释放资源并停止编码器。以下是示例代码：

// 释放资源
AMediaCodec_stop(codec);
AMediaCodec_delete(codec);
AMediaFormat_delete(format);

glDeleteTextures(1, &textureID);

eglDestroySurface(eglDisplay, eglSurface);
eglMakeCurrent(eglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
eglDestroyContext(eglDisplay, eglContext);
eglTerminate(eglDisplay);