before iOS8, I use ALAsset and use buffer to get NSData then upload video like below;
Byte * buffer = (Byte *)malloc(lenght);
NSError * error = nil;
NSUInteger readLength = [self.asset.defaultRepresentation getBytes:buffer fromOffset:self.sendedSize length:lenght error:&error];
NSData * data = [NSData dataWithBytes:buffer length:readLength];
so, how can i upload video use PhotoKit? How can i get the video data?