Comment by ErroneousBosh
15 days ago
Okay, so what you're doing there is averaging the information between the two fields.
That gives you 25fps. It can only ever give you 25fps.
There are 50 fields per second, for 25 frames per second.
If you average the odd and even fields, you get 25 frames per second.
Untrue.
Let's suppose we fill odd fields with black, and even fields with white.
The end result when played back on a CRT will be the entire screen flickering between black and white with a lot of flicker, phosphor persistence notwithstanding.
If you simply average the even and odd fields, you will be left with the completely incorrect result of 50% gray and zero change between image frames.
You seem to be under the misconception that two consecutive fields contain image from the same moment in time. This is not necessarily true with proper interlaced video.