TV Presentation with a MacBook Pro
In the old style MacBook the output was analogue which could be fed into an old style TV without problems.
The new MacBook Pro however has a digital output which must be converted into analogue via 'a converter box' in order for it to work with an old style TV. However this digital signal works fine with an HD TV (and, presumably, the analogue signal would not). Furthermore, I suspect this digital signal may not work with some digital projectors either.
So, since I still have my old MacBook I might be better off converting all my movies to run on that if I am likely to encounter a non-HD TV. But that would mean that I might have a problem with screen size. My old MacBook has a standard-sized screen (which I can accommodate on iMovie) whereas most TVs (HD or not) are now wide-screen, so maybe everything will be distorted unless I can somehow change the screen size of the TV. Maybe I should take both laptops to future events - just to be on the safe side.