[MPlayer-users] mencoder options for NTSC television

[D Richard Felker III]

On Fri, Jan 17, 2003 at 02:54:27PM -0600, Lance Simmons wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> On Fri, Jan 17, 2003 at 11:23:01AM -0500, D Richard Felker III wrote:
> > On Fri, Jan 17, 2003 at 08:41:11AM -0600, Lance Simmons wrote:
> > > 
> > > The one thing I'm still not sure about is the resolution I should use.
> > > You suggest 640x480.  Why?  What's the relationship between the NTSC
> > > standard and the resolution one chooses? 
> > 
> > NTSC has 480 lines (visible), and 640 is the corresponding width that
> > will give you square pixels for a 4:3 aspect picture. 
> 
> After I've cropped it to get rid of the black sections, it ends up being
> less than 640x480.  Should I resize the original capture to be larger so
> that the cropped version ends up being 640x480?  It sounds like I
> shouldn't, at least not for height, since 480 is crucial.

Well rescaling it with mencoder wouldn't really hurt, since mplayer's
software scaler is much higher quality than the 'naive' stuff I
described in the capture hardware. But there's no real reason to scale
it back up to 640x480 either. However, if cropping leaves it at a size
that's not a multiple of 16, you might want to scale to the nearests
multiples of 16 or crop a little bit more.

> So do I understand correctly that the end result of the two-step
> procedure you describe will always be less than 640x480?

Yes, that's what I had in mind. Of course sometimes the TV picture may
run all the way to the borders, in which case cropping could be
skipped. I don't have cable tv though, nor do I have a good antenna,
so most of my testing of videocapture has been with a playstation2,
which has fairly large black borders that need cropping. :)

Rich