AVAudioplayer не может этого сделать, AVPlayer может.
// play audio file as NSURL *url;
NSDictionary *options = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:NO]
forKey:AVURLAssetPreferPreciseDurationAndTimingKey];
AVURLAsset *urlAsset = [AVURLAsset URLAssetWithURL:url options:options];
NSString *tracksKey = @"tracks";
[urlAsset loadValuesAsynchronouslyForKeys:[NSArray arrayWithObject:tracksKey] completionHandler:
^{
// Completion handler block.
dispatch_async(dispatch_get_main_queue(),
^{
NSError *error = nil;
AVKeyValueStatus status = [urlAsset statusOfValueForKey:tracksKey error:&error];
if (status == AVKeyValueStatusLoaded) {
self.avPlayer = [AVPlayer playerWithPlayerItem:playerItem];
[avPlayer play];
avPlayer.rate = 0.5;
}
else {
// You should deal with the error appropriately.
NSLog(@"The asset's tracks were not loaded:\n%@", [error localizedDescription]);
}
});
}];