AVPlayer -Play sound while seeking/scrubbing - ios

Question

I have a uislider attached to my avplayer, is there a way to play sound from the video while scrubbing?
var player: AVPlayer?
func createPlayer() {
player = AVPlayer()
// init player with playerItem, asset, eventually add to playerLayer ...
player?.volume = 1
}
#objc func sliderValueChanged(_ slider: UISlider) {
let sliderValue = slider.value
let seekTime = CMTimeMakeWithSeconds(Double(sliderValue), preferredTimescale: 1000)
player?.seek(to: seekTime, toleranceBefore: .zero, toleranceAfter: .zero)
}

Answer 1

Since the UISlider's values update continuously while you interact with it, the AVPlayer doesn't get a chance to play any audio since the seek function gets executed every time the slider's value is updated.
I used this SO example from the comments with some minor tweaks to get this working
At a high level:
You need to add a second AVPlayer which will be responsible for playback during scrubbing
When you start scrubbing, start playing the video in the second AVPlayer from where the first player currently was
As soon as you start playing the second player, it should be locked from being updated by the scrubber and it should play for a short period of of time 1/4 to 1/2 a second (experiment with the time duration)
After this time has elapsed, pause the second player and open it to be updated again - this is what creates that jagged noise
Here is a small example that gave me something close to what you are after:
import UIKit
import AVKit
class AVPlayerScrubVC: UIViewController {
let playerViewController = AVPlayerViewController()
var player: AVPlayer?
var player2: AVPlayer?
var isScrubbingLocked = false
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
title = "Player Scrub"
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
configurePlayer()
configureScrubber()
}
private func configurePlayer()
{
// Add your own video URL
let videoURL
= Bundle.main.url(forResource: "sample_1",
withExtension: "mp4")
if let videoURL = videoURL {
player = AVPlayer(url: videoURL)
player2 = AVPlayer(url: videoURL)
player2?.volume = 5
playerViewController.player = player
playerViewController.showsPlaybackControls = false
// Add the AVPlayerController as a child of the current
// view controller
self.addChild(playerViewController)
// Configure the player view
let playerView = playerViewController.view
playerView?.backgroundColor = .clear
playerView?.frame = self.view.bounds
// Add the AVPlayerViewController's view as a subview
// of the current view
self.view.addSubview(playerView!)
playerViewController.didMove(toParent: self)
// Start playing the content
playerViewController.player?.play()
}
}
// Configure the UISlider
private func configureScrubber() {
let slider = UISlider()
slider.translatesAutoresizingMaskIntoConstraints = false
slider.minimumValue = 0
let videoTime
= Float(CMTimeGetSeconds((player?.currentItem?.asset.duration)!))
slider.maximumValue = videoTime
slider.addTarget(self, action: #selector(sliderValueChanged(_:)),
for: .valueChanged)
view.addSubview(slider)
view.addConstraints([
slider.leadingAnchor
.constraint(equalTo: view.leadingAnchor,
constant: 16),
slider.bottomAnchor
.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor,
constant: -16),
slider.trailingAnchor
.constraint(equalTo: view.trailingAnchor,
constant: -16),
slider.heightAnchor
.constraint(equalToConstant: 70)
])
}
#objc
func sliderValueChanged(_ slider: UISlider) {
let sliderValue = slider.value
let seekTime = CMTimeMakeWithSeconds(Double(sliderValue),
preferredTimescale: 1000)
player?.seek(to: seekTime,
toleranceBefore: .zero,
toleranceAfter: .zero)
if !isScrubbingLocked {
audioScrub(to: seekTime)
}
}
func audioScrub(to currentTime: CMTime) {
DispatchQueue.main.async {
// Lock the scrubbing
self.isScrubbingLocked = true
// play the simultaneous player
self.player2?.play()
// make sure that it plays for at least 0.5 of a second
// before it stops to get that scrubbing effect
// Play around with the delay to get the results best for you
DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
// now that 1/2 of a second has passed
// (you can make it longer or shorter as you please)
// - pause the simultaneous player
self.player2?.pause()
// now move the simultaneous player to the same point as the
// original video player:
self.player2?.seek(to: currentTime)
// setting this variable back to true allows the process to be
// repeated as long as video is being scrubbed:
self.isScrubbingLocked = false
}
}
}
}