PdfCommon.Initialize();
           var doc = PdfDocument.Load(@"d:\0\9\mp4.pdf");
           var page = doc.Pages[0];
           var dict = page.Dictionary;
           var annots = ((dict["Annots"] as PdfTypeIndirect).Direct) as PdfTypeArray;
           var annotation = ((annots[0] as PdfTypeIndirect).Direct) as PdfTypeDictionary;
           if ((annotation["Subtype"] as PdfTypeName).Value == "RichMedia")
           {
               //this is your media dictionary
               var mediaSettings = annotation["RichMediaSettings"] as PdfTypeDictionary;
               var mediaContent = (annotation["RichMediaContent"] as PdfTypeIndirect).Direct as PdfTypeDictionary;
               var names = ((mediaContent["Assets"] as PdfTypeIndirect).Direct as PdfTypeDictionary)["Names"] as PdfTypeArray;
               for(int i = 0; i< names.Count; i+=2)
               {
                   string filename = (names[i] as PdfTypeString).UnicodeString;
                   var fileDict = (names[i + 1] as PdfTypeIndirect).Direct as PdfTypeDictionary;
                   var stream = ((fileDict["EF"] as PdfTypeDictionary)["F"] as PdfTypeIndirect).Direct as PdfTypeStream;
                   var data = new byte[stream.Length];
                   stream.Read(0, data.Length, data);
                   System.IO.File.WriteAllBytes(string.Format(@"d:\0\9\Files\{0}", filename), data);
               }
           }