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Or GotSent will remux them for you, takes about 10 minutes for a full length movie.
 
Never used the app myself, but based on the descriptions, it should work with a peer-to-peer WiFi connection between your MacBook Pro and the iPad. No need for a server at home, or an access point on the train. But then, why not just watch on the MacBook Pro? Ergonomics? It would still need to be on to do the live conversion.
The main reason? Battery life. The iPad kills my early 2008 15" MBP. The MBP lasts 1.5 hours if I'm lucky. With the iPad I get roughly 7 times that.

No, that's what it says. It's no surprise: it just hands off the video to the built-in QuickTime and the hardware accelerated video decoder. Anything else would kill the battery.
This makes a lot sense! Thanks for pointing that out.
 
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