IOS8:录制到文件并使用 AVCaptureSession/commitConfiguration 时相机预览闪烁

Question

从IOS8开始，我在使用commitConfiguration时遇到了一个奇怪的问题 我们通过 AVCaptureMovieFileOutput 录制 5 秒的文件。更改文件时，相机预览会闪烁并褪色一秒钟。在接收服务器上缝合文件时也会出现卡顿现象。

// method that switches the output file
- (void) switchOutputFile {
    NSURL *outputUrl = [self getOutputFileUrl];
    NSLog(@"Switching to: %@", outputUrl);

    // begin configuration
    [self.captureSession beginConfiguration];

    // remove the current writer
    [self.captureSession removeOutput:self.fileOutput];

    // attach new writer
    self.fileOutput = [self attachFileWriter:self.captureSession];

    // commit configuration
    [self.captureSession commitConfiguration];

    // after this line the camera preview flickers.
    [self.fileOutput startRecordingToOutputFileURL:outputUrl recordingDelegate:self];
  } 

Answer 1

解决办法很简单——不删除并添加writer。感谢苹果公司bford的解释! 这是更新后的函数方法

// method that switches the output file
- (void) switchOutputFile {
    NSURL *outputUrl = [self getOutputFileUrl];
    NSLog(@"Switching to: %@", outputUrl);
    [self.fileOutput startRecordingToOutputFileURL:outputUrl recordingDelegate:self];
}