[MacDV] Re: Converting 4:3 to 16:9

[Mark M.Florida]

On Oct 6, 2005, at 6:11 PM, sb wrote:

> Interlacing doesn't scale, the pixels do. The line size doesn't change.

Hold on just a sec.  How do you think a frame of digital video is 
interlaced?  Each row of pixels is a different field.  Example:

Here's your interlaced video signal at 100% scale (1 is field 1, 2 is 
field 2):

11111111111111111111111111111
22222222222222222222222222222
11111111111111111111111111111
22222222222222222222222222222
11111111111111111111111111111
22222222222222222222222222222
11111111111111111111111111111
22222222222222222222222222222

If you blow that up 200%, the video will look like this in the same 
viewable area:

11111111111111111111111111111
11111111111111111111111111111
22222222222222222222222222222
22222222222222222222222222222
11111111111111111111111111111
11111111111111111111111111111
22222222222222222222222222222
22222222222222222222222222222

So, that's how the interlacing scales.  Interlacing isn't magic -- it's 
just pixels, so if you scale the pixels, the interlacing is scaled as 
well, and you will see the lines prominently, especially in areas of 
motion.

On the other hand, if you *de-interlace* the fields first and THEN 
scale it, it might look better, but de-interlacing involves duplication 
or interpolation of the interlaced lines of pixels, so it's not going 
to look perfect.

On the other other hand, if you shoot progressive-scan video, there is 
no interlacing and the scaling will look much cleaner.

Way more than 2 cents.

- Mark