No, .cap files are used to decode the 4 way handshake by brute force dictionary attacks only when you don't have the luxury of a WPS pin facility on the AP. Although there is some software out there that can use the GPU for decode as well as quad cores to speed things up, you can still expect to be waiting around a very long time. Sometimes for nothing at all more often than not. Depends on the stupidity of the password maker, the quality of your password lists, or whether the target AP has well known combinations for a dictionary attack. Getting a dictionary word matched to a 4 way handshake in the first place should be considered really lucky because the likely combinations are far too numerous, like getting a royal flush in poker twice in a row. The longer the amount of characters in the password, the greater the time expended and the less likely you are to even get the password. For getting the WPS pin itself it's Reaver for that job. And Reaver has nothing to do with .cap handshake capture files, so it's impossible to derive any WPS pin from the .cap.
