Shift AVPlayer captions when subview overlaps them

问题

Is it possible to shift the system captions that display for a video should a subview (non-native, custom player controls) appear over them? The captions displayed are text WebVTT captions.

On certain screen sizes, when I shift to landscape, our custom seek bar controls overlap captions that appear at the bottom of the player.

回答1:

For what it's worth, this is possible. You need to access the AVPlayer's current item and set an AVTextStyleRule for it.

// currentPlayer is our instance of the AVPlayer
if let currItem = currentPlayer?.currentItem {
  let rule = AVTextStyleRule(textMarkupAttributes: [kCMTextMarkupAttribute_OrthogonalLinePositionPercentageRelativeToWritingDirection as String: 93]) 
  // 93% from the top of the video
  currItem.textStyleRules = [rule!]
}

来源：https://stackoverflow.com/questions/39660855/shift-avplayer-captions-when-subview-overlaps-them