avplayer has no sounds when play video

Question

here is all my codes for play a mp4,the mp4 is playing but no sounds out

import UIKit

import AVFoundation
class ViewController: UIViewController {

@IBOutl         


        

Answer 1

For Swift 4.2, put following lines in viewDidLoad

do {
    try AVAudioSession.sharedInstance().setCategory(.playback, mode: .default, options: [])
}
catch {
    print("Setting category to AVAudioSessionCategoryPlayback failed.")
}