如何实现前置镜头的录像镜像功能

录像的前置镜头录像，需要开启镜像功能，调用enableMirror()可以启用/关闭镜像录像。

启用镜像录像前需要先通过isMirrorSupported查询是否支持录像镜像功能，示例代码如下：

function testIsMirrorSupported(videoOutput: camera.VideoOutput): boolean {
  let isSupported: boolean = videoOutput.isMirrorSupported();
  return isSupported;
}

• 若支持录像镜像功能，调用enableMirror()可以启用/关闭镜像录像。示例代码如下：

  import { camera } from '@kit.CameraKit';
  import { media } from '@kit.MediaKit';
  import { BusinessError } from '@kit.BasicServicesKit';
  
  // ...
  
  function enableMirror(videoOutput: camera.VideoOutput, mirrorMode: boolean): void {
    try {
      videoOutput.enableMirror(mirrorMode);
    } catch (error) {
      let err = error as BusinessError;
    }
  }

  启用/关闭录像镜像后，需要通过getVideoRotation以及updateRotation更新旋转角度。

• 若不支持录像镜像功能，可以使用rotate实现组件翻转效果，对预览流进行镜像，方便用户对录像内容进行预览，之后对录像文件单独处理，利用三方库FFmpeg实现录像文件的内容镜像。

  1. 录像预览流设置：使用rotate对预览流组件XComponent进行镜像翻转，代码示例如下：

     // Flip Angle
     @State angle: number = 180;
     // Use rotate to control whether the preview stream component XComponent is mirrored
     XComponent({
       type: XComponentType.SURFACE,
       controller: this.mXComponentController,
       imageAIOptions: {
         types: [ImageAnalyzerType.SUBJECT],
         aiController: this.aiController
       }
     })
       .onLoad(() => {
         // The aspect ratio of the preview stream must match that of the recording output stream
         this.mXComponentController.setXComponentSurfaceRect({
           surfaceWidth: this.videoSize.width,
           surfaceHeight: this.videoSize.height
         });
         this.surfaceId = this.mXComponentController.getXComponentSurfaceId()
       })
       .width(StyleConstants.FULL_WIDTH)
       .height(StyleConstants.XCOMPONENT_HEIGHT)
       .rotate({ y: 1, angle: this.angle, })

  2. 使用FFmpeg三方库的能力，对录像文件内容镜像。执行镜像操作前，需要先安装，具体步骤可参考FFmpeg官网。镜像命令执行代码如下：

     import { FFProgressMessageParser, FFmpeg } from '@sj/ffmpeg';
     
     let commands = ["ffmpeg", "-i", inputPath, "-vf", "hflip", outputPath];
     FFmpeg.execute(commands, {
       logCallback: (logLevel: number, logMessage: string) => console.log(`[${logLevel}]${logMessage}`),
       progressCallback: (message: string) =>  console.log(`[progress]${JSON.stringify(FFProgressMessageParser.parse(message))}`),
     }).then(() => {
       console.info("FFmpeg execution succeeded.");
     }).catch((error: Error) => {
       console.error("FFmpeg execution failed with error: ${error.message}");
     });