[mythtv-users] interlaced vs not?

[Chris Petersen]

I'm slightly confused about the definition of this word in relation to
the encoding settings....    I understand interlacing's two meanings.. 
one, as in those old interlaced monitors, which also applies to tv sets:

- - - -     where - is a pixel.
 - - - 
- - - -

And I also understand frame-interlacing as in a DVD (too hard to draw in
ascii).

Anyway, which one of these is myth talking about, when it says that the
encoding option (I forget what it's called) helps with an interlaced
source?  I assume it's closer to the second definition (I can't imagine
how it would apply to the first), but in that case, how do I know if my
source is interlaced or not?

-Chris