I am just working on this, and so far have the following:
- (NSTimeInterval) availableDuration;
{
NSArray *loadedTimeRanges = [[self.player currentItem] loadedTimeRanges];
CMTimeRange timeRange = [[loadedTimeRanges objectAtIndex:0] CMTimeRangeValue];
Float64 startSeconds = CMTimeGetSeconds(timeRange.start);
Float64 durationSeconds = CMTimeGetSeconds(timeRange.duration);
NSTimeInterval result = startSeconds + durationSeconds;
return result;
}