How good is HD supposed to be?

[Dave Liquorice]

On Fri, 29 Apr 2016 20:42:06 +0100, Christopher Woods wrote:

> "Upscaling" is a misnomer in this context. That implies a change of 
> picture resolution, ...

Agreed. 

> ... when there's no resizing going on. 

Not convinced.

> 25 interlaced frames per second yields 50 interlaced fields per second 
> (due to odd and even line scanning), 

But does a frame have the same number of lines as a field? It doesn't in the 
analog world. 625 line frame, comprising two 312.5 line fields. Frame rate 
25 per second, field rate 50 per second but half the vertical resolution.

If a digital field only has half the vertical resolution, which I think it 
must have or you can't interlace them, then to create true 50 *frames* per 
second each field needs to be upscaled and the missing lines interpolated 
from the existing ones. If you just construct a frame from the two fields 
you have to repeat that frame or playback at double speed...

I missing something but don't know what.

-- 
Cheers
Dave.