public APLCompositionTrackSegmentInfo(AVCompositionTrackSegment segment, string mediaType)
        {
            if (segment.Empty)
                TimeRange = segment.TimeMapping.Target;
            else
                TimeRange = segment.TimeMapping.Source;

            Empty = segment.Empty;
            MediaType = mediaType;

            NSString url = new NSString (segment.SourceUrl != null ? segment.SourceUrl.AbsoluteString : string.Empty);
            description = GetDescription (url.LastPathComponent);
        }
        public APLCompositionTrackSegmentInfo(AVCompositionTrackSegment segment, string mediaType)
        {
            if (segment.Empty)
            {
                TimeRange = segment.TimeMapping.Target;
            }
            else
            {
                TimeRange = segment.TimeMapping.Source;
            }

            Empty     = segment.Empty;
            MediaType = mediaType;

            NSString url = new NSString(segment.SourceUrl != null ? segment.SourceUrl.AbsoluteString : string.Empty);

            Description = GetDescription(url.LastPathComponent);
        }