Put this line before calling play() method of AVPlayer.
In Objective C
[[AVAudioSession sharedInstance]
setCategory: AVAudioSessionCategoryPlayback
error: nil];
In Swift
do {
try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback)
} catch {
// report for an error
}
Swift 5
do {
try AVAudioSession.sharedInstance().setCategory(.playback)
} catch(let error) {
print(error.localizedDescription)
}