[MEncoder-users] Noise reduction and interlacing: (hq)denoise3d vs. nr

[Dieter]

> > > f1 and f2 or f2 and f3 do not belong to the same actual frame, so a
> >
> > I suppose you mean scanline? Like what Nico said, top field/bottom field.
> 
> You are right
> 
> "interlaced" frame, F = { l1, l2, l3, ... }  = 2 sets of scan lines
> interleaved in a "frame", but actually two fields :
> top(t0) = { l1, l3, l5, ... }, bottom(t0+delta_t) = { l2, l4, l6, ...
> } with delta_t=1/50s or 1/60s
> 
> sorry about the confusion, I'm not sure to use the right terms.

Doesn't this depend on exactly what technology was used to record?
If the original source is film, then both fields were captured at
the same time.  If the original source is an interlaced video camera,
then one field would be captured at a different time than the other.
If the original source is a acanning interlaced video camera, then
each scan line would be captured at a slightly different time
(and different times even within a scan line)  Even with film,
different parts of the image might be from slightly different times
depending on what type of shutter was used.