Are you trying to convert .wtv to .dvr-ms? In Windows 7, you can right click on a .wtv file and convert to .dvr-ms. This works in Windows 8 as well, but Windows Media Center has to be added in, and it is no longer free.
Most people who edit .wtv or .dvr-ms do so on their computer. There is a program called VideoReDo TV Suite which is designed to work with them. Not free, but if you only have a few .wtv files to edit, there is a free trial available for this program.
If neither of these answers are what you are looking for, I'd suggest asking in the videohelp.com forums, or wait a bit and see what others here might have to suggest.