How do you get smooth high-rate playback from AVPlayer?

Question

AVPlayer has a property called rate that is meant to control the playback rate. 1.0 is normal speed while values like 2.0 or

Answer 1

This is only a workaround.

When the playback rate is changed from 0.0 to a large value, if this is the first zero-to-nonzero transition in playback rate since the last call to AVPlayer.replaceCurrentItem, playback is smooth (and audio is automatically muted). It is necessary that this is the first such transition: merely setting the rate to 0.0 first and then to the desired rate does not work.

So, for example, this will produce smooth playback at high speeds:

func setPlayerRate(player: AVPlayer, rate: Float) {
    // AVFoundation wants us to do most things on the main queue.
    DispatchQueue.main.async {
        if (rate == player.rate) {
            return
        }
        if (rate > 2.0 || rate < -2.0) {
            let playerItem = player.currentItem
            player.replaceCurrentItem(with: nil)
            player.replaceCurrentItem(with: playerItem)
            player.rate = rate
        } else {
            // No problems "out of the box" with rates in the range [-2.0,2.0].
            player.rate = rate
        }
    }
}