How can I remove the black bar from meeting video (Top and Bottom)

XCode 13.2
macOS 11
zoom-sdk-ios-5.9.1.2191

We can’t get a fullscreen video,How can I remove the black bar from meeting video (Top and Bottom)
We use customMeeting,The video custom ocde:

  • (MobileRTCVideoView*)videoView
    {
    if (!_videoView)
    {
    self.view.frame = CGRectMake(0,0,self.view.frame.size.width,self.view.frame.size.height);

      _videoView = [[MobileRTCVideoView alloc] initWithFrame:self.view.frame];
      //_videoView = [[MobileRTCVideoView alloc] initWithFrame:self.view.bounds];
      [_videoView setVideoAspect:MobileRTCVideoAspect_PanAndScan];
    

    }
    return _videoView;
    }

We use MobileRTCVideoAspect_PanAndScan or MobileRTCVideoAspect_Full_Filled- so the video does not cover the full area,It seems doesn’t work

In your screenshot the video ratio is 4:3 (not 16:9) - perhaps a zoom limitation for some (?) mobil phones

it seems to be in the normal zoom app also:

Thanks Jürgen!
The tool we tested was iPhone 11,When we use this device to communicate with each other on Zoom, the screen can be full,Maybe this is not a problem with the equipment