The TMediaPlayer component in Rad Studio 10.3 works fine but it does not have any facility to invoke the audio controls in iOS when screen is locked. This results in apps submitted to the Apple store being rejected if they use background audio (plays while app not up) because they don't show the audio controls. Per Apple (Apple Developer Documentation) this requires using the media player framework's MPRemoteCommandCenter and MPNowPlayingInfoCenter classes. Doesn't seem to be a way to do this with FMX now.