我得到了正确的FPS与下面的代码行：

AVAsset * myAsset = [[AVURLAsset alloc] initWithURL: _videoUrl options: nil];
AVAssetTrack * videoAssetTrack = [myAsset tracksWithMediaType: AVMediaTypeVideo].firstObject;
NSLog(@"FPS is  : %f ", videoAssetTrack.nominalFrameRate);

Swift 5的AVAsset扩展

extension AVAsset {
   /**
    * Get FPS from AVAsset
    */
   var fps: Float? {
      self.tracks(withMediaType: .video).first?.nominalFrameRate
   }
}

• • iOS 16操作系统**

通过异步使用Load属性，您可以从Swift并发开发中获益，以检索FPS、size or dimension和duration。

var asset: AVAsset? = AVAsset(url: filePath)
if let asset = asset,
   let videoTrack = try? await asset.loadTracks(withMediaType: .video).first {

     let size = try? await videoTrack.load(.naturalSize)
     let fps = try? await videoTrack.load(.nominalFrameRate)
     let duration = try? await asset.load(.duration)
}