自定义视频渲染

2.3 处理帧

buffer回调的处理：

- (bool)handleBeautyProcessBuffer:(CVPixelBufferRef)pixelBufferRef {
    if (!self.beautyEngine) {
        [self initBeautyEngine];
    }
    if (self.beautyEngine && pixelBufferRef)
    {
        QEPixelBufferData *bufferData = [QEPixelBufferData new];
        bufferData.bufferIn = pixelBufferRef;
        bufferData.bufferOut = pixelBufferRef;
        // 对pixelBuffer进行图像处理，输出处理后的buffer
        kQueenResultCode resultCode = [self.beautyEngine processPixelBuffer:bufferData];//执行此方法的线程需要始终是同一条线程
        if (resultCode == kQueenResultCodeOK && bufferData.bufferOut)
        {
            return YES;
        }
    }
    return NO;
}

纹理回调的处理：

- (bool)handleBeautyProcessTexture:(int)textureID withWidth:(int)width withHeight:(int)height {
    // 见下文纯纹理处理模式
}

3 创建美颜处理器

- (void)initBeautyEngine:(BOOL)processBuffer
{
    if (self.beautyEngine != nil) {
        return;
    }
    // 初始化引擎配置信息对象
    QueenEngineConfigInfo *configInfo = [QueenEngineConfigInfo new];

    // 设置是否自动设置图片旋转角度，如设备锁屏，并且默认图像采集来自摄像头的话可以设置自动设置图片旋转角度
    configInfo.autoSettingImgAngle = YES;
    
    configInfo.runOnCustomThread = processBuffer ? NO : YES; // 纹理调用时，为YES，buffer调用时，为NO，NO表示不运行在当前调用者线程，内部会创建一个新线程
    configInfo.withContext = processBuffer ? YES : NO;        // 纹理调用时，为NO，buffer调用时，为YES，YES表示需要内部创建glContext
    
    // 调试接口，开启美颜sdk日志功能
    // configInfo.enableDebugLog = YES;

    // 引擎初始化
    self.beautyEngine = [[QueenEngine alloc] initWithConfigInfo:configInfo];
    
    ...
    // 其他保持相同
}

4 处理帧

- (int)handleBeautyProcessTexture:(int)textureID withWidth:(int)width withHeight:(int)height {
    if (!self.beautyEngine) {
        [self initBeautyEngine:NO];
    }

    // 高级美颜功能需要人脸检测算法，因此需要额外传入bufData。
    // 如果仅开基础美颜，则不用调用updateInputDataAndRunAlg方法。
    uint8_t* bufData = [self extractI420DataFromPixelBuffer:videoSample.pixelBuffer];
    [self.beautyEngine updateInputDataAndRunAlg:bufData
                                            withImgFormat:kQueenImageFormatNV12
                                            withWidth:width
                                            withHeight:height
                                             withStride:0
                                         withInputAngle:0
                                        withOutputAngle:0
                                           withFlipAxis:0];
    free(bufData);
    
    QETextureData* textureData = [[QETextureData alloc] init];
    textureData.inputTextureID = textureID;
    textureData.width = width;
    textureData.height = height;
    kQueenResultCode result = [self.beautyEngine processTexture:textureData];
    if (result != kQueenResultCodeOK)
    {
        return textureID;
    }
    return textureData.outputTextureID;
}

纹理模式处理时，为提升整体性能，避免从纹理中再次提取buffer数据，因此需要应用层，将buffer提取出来传递给美颜SDK，调用接口。

以下为buffer提取示例代码：

-(uint8_t *)extractI420DataFromPixelBuffer:(CVPixelBufferRef) pixelBuffer {
    uint8_t *bufData = nil;
    // 获取格式信息
    OSType pixelFormat = CVPixelBufferGetPixelFormatType(pixelBuffer);
    size_t bufWidth = CVPixelBufferGetWidth(pixelBuffer);
    size_t bufHeight = CVPixelBufferGetHeight(pixelBuffer);
        
    // 锁定buffer
    CVPixelBufferLockBaseAddress(pixelBuffer, kCVPixelBufferLock_ReadOnly);
    
    if (CVPixelBufferIsPlanar(pixelBuffer)) {
        if (pixelFormat == kCVPixelFormatType_420YpCbCr8BiPlanarFullRange) {
            uint8_t *yPlane = (uint8_t *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0);
            uint8_t *uvPlane = (uint8_t *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1);

            size_t yStride = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 0);
            size_t uvStride = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 1);

            size_t width = CVPixelBufferGetWidth(pixelBuffer);
            size_t height = CVPixelBufferGetHeight(pixelBuffer);
            // 分配标准NV12大小（无padding）
            size_t bufDataSize = width * height * 3 / 2;
            bufData = (uint8_t *)malloc(bufDataSize);
            // 逐行拷贝Y平面（去除stride padding）
            for (size_t i = 0; i < height; i++) {
                memcpy(bufData + i * width, yPlane + i * yStride, width);
            }
            // 逐行拷贝UV平面
            for (size_t i = 0; i < height / 2; i++) {
                memcpy(bufData + width * height + i * width,
                       uvPlane + i * uvStride,
                       width);
            }
        }
        
    } else {
        // 打包格式（如BGRA）
        void *baseAddress = CVPixelBufferGetBaseAddress(pixelBuffer);
        size_t dataSize = CVPixelBufferGetDataSize(pixelBuffer);
        // 处理baseAddress
        bufData = (uint8_t *)malloc(dataSize);
        memcpy(bufData, baseAddress, dataSize);
    }
    CVPixelBufferUnlockBaseAddress(pixelBuffer, kCVPixelBufferLock_ReadOnly);

    return bufData;
}