DVD fails intermittenly

I can get some DVD's to play perfectly. And then all of sudden one will just lock up...or freeze/stop. I stop it, fast forward it, etc and then it will play for a while and then lock again.

I have taken rental DVD's back and replace with another copy and get the same results. I have replaced concert DVD's with another copy and get the same results. But, yet I can play a totally different DVD (concert) and it plays flawlessly through the entire DVD.

I assume it is the DVD player? And if so is it worth trying to have it serviced on a 5 year TV set. I imagine I could buy an external DVD player for under a $100 and just plug it in the TV.

**** Peterson