ConvertFPS

[manolito]

Here is a question for the AviSynth gurus (Gavino, IanB, you know who you are...)

For converting a true progressive 30 fps clip to 25 fps I like the field based method from this post:
http://forum.doom9.org/showthread.php?p=908303#post908303

AssumeTFF()
LanczosResize(720,576)
changefps(50)
separatefields()
selectevery(4,0,3)
weave

I suppose the result will be identical if I first duplicate every frame before the command ChangeFPS(50) like this:
interleave(last,last)
changefps(50)

But what if I use ConvertFPS? If I double the frame rate to 60 fps first and then use ConvertFPS to go down to 50 fps, will there be less blending compared to going directly from 30 to 50?


Just curious...

Cheers
manolito

[colours]

Three fields out of every five will be clean; the remaining two will be blended. (Selecting those three clean fields and deinterlacing would recover the source, albeit with half vertical resolution.)

A normal ConvertFPS would result in four blended fields and only one clean field out of every five fields.

[manolito]

Thanks colours for the explanation (even if I do not understand the math behind it... :o )

So my suspicion that the method which uses frame doubling before ConvertFPS gives better looking results with less blending was correct. Good to know.


Cheers
manolito