[MEncoder-users] Trying to fully understand de-interlacing.

[Carl Eugen Hoyos]

Andrew Berg <bahamutzero8825 <at> gmail.com> writes:

> For regular end-users like you and I, there is rarely reason to have
> interlaced material,

rarely? Or never?

> but for broadcasting, the standard is to have
> either 60 frames per second or 60 fields per second (50 for PAL).
> 1080p60 uses too much bandwidth, so 1080i60 is used.

I know, I don't doubt that, I am trying to explain that it is a _very_ bad idea
(if you don't have a HDTV CRT with 60fps - afaik, this can't be bought)

> 24p content can be telecined the same way it always has.

Living in PAL country (and seeing different other bad things, like slowing a
movie - randomly doubling frames - to get more ad-breaks), I fortunately do not
suffer from telecine.

> I do not know exactly why, but one cannot broadcast 1080p30 (or 1080p25),

That's wrong: 24 (and 25) fps material is sent (in PAL country) in something
they call 1080i50, but it cannot be visually distinguished from 1080p25, which
makes it 1080p25 "for regular end-users like you and I".

My point was something else:
Movies and (modern) television series are no problem (as explained before) - at
least as long as we are talking about PAL, they are sent as 25 fps progressive
material (no matter how they call it), But live material recorded in 50 fields
is sent in something that the "display" (software, GPU or TV) has to process to
make it endurable for human eyes.
That's why I believe the original EBU decision to prefer 720p50 over 1080i50 was
correct for self-produced material and would especially make a huge (positive)
difference for sports if it would be recorded that way (which it isn't
supposedly because of the other broadcasters).

Does somebody know why it is not possible for the broadcaster to change between
720p50 and 1080"i"50 depending on the current program? Are those "certified"
receivers so bad that they can't decode it correctly?

Carl Eugen