the duration of a mp3 returns zero

Question

I want to get the duration of a mp3 file from the internet,I use the following code:

NSURL *url = [NSURL fileURLWithPath:@"http://view.33591.com:586/2012/11/30/11/4207369.mp3"];    
AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:url
                                            options:nil];
CMTime time = asset.duration;
float seconds = CMTimeGetSeconds(time);
NSLog(@"seconds:%f",seconds);

but it always returns 0,if I change the url to a local file from the bundle,it works fine.So is there a way to do that correctly?

Answer 1

NSURL *url = [NSURL fileURLWithPath:@"http://view.33591.com:586/2012/11/30/11/4207369.mp3"];

The URL you provide is not a filesystem path. Use [NSURL URLWithString:] instead, and do read the documentation of the NSURL class and in particular the methods you are seeking to use.

fileURLWithPath:

Initializes and returns a newly created NSURL object as a file URL with a specified path.

(emphasis mine)