I can't think of a reason why the .com would be better than the .tv. Although there has been many threads about one extension being preferred over another there has never been any conclusive proof tabled. Obviously, .coms have been around longer to gain many of the attributes required to increase ranking in the serps. However, all things being equal you a better off with a shorter and hopefully more generic domain. Great that with a .tv you are going to feature video. I'm a fan of .tv and see a bright future for an extension that promises to show users all the colour movement sound and excitement that only Video/tv can show. Hope you will let us know how you get on.
there has never been any conclusive proof tabled
I have it after testing hundreds of Tlds and it is not quite so equal as many believe it is supposed to be however that is not the question in hand.
Presumably you're going global and not directing it at any one specific region or country? If so then host in the USA for maximum Google love, it can be very difficult to get a .com registered and hosted in another country to even rank in Google.com these days so accurate/delicate/quirky is their geo-targetting.
Ensure your titlebar, keywords and description tags are all completed and accurately reflect the on-page information.
Whether to be .com or .tv?
My gut reaction is the .com however if the example.tv is a seriously good brandable name I would be very tempted to go with that.
Another advantage of going with .tv is that quite possibly other video/media sites may be willing to link to you quicker and more easily than the .com...that's another gut reaction as well...and what about your business cards when discussing those mega media deals:
highlander355 [ at ] example.tv
highlander355 [ at ] example.com
Hey, must go get me one:-)