convert 50i into 25p

How can i convert 50i into 25p on fcp7....????
I wanna slowmo some shots and the rest normalement speed(25p) !?!?
thanks

mikalordet: You are asking how to deinterlace some of the 50i to 25p and to "double deinterlace" some of the 50i to 50p, and then to stick the 50p in amongst the 25p as slowmo.
I don't think FCP7 can do the first deinterlace decently or the second deinterlace at all. If you have FCP7 then you probably also have Compressor and Cinema Tools. If so do the following:

Put the 50i material you wish to deinterlace to 25p into Compressor. In Inspector, in Video Settings, for Frame Rate select 25. Deselect Interlaced. In Frame Controls, set Output Fields to Progressive. For Deinterlace choose "Better (Motion adaptive)", since Compressor's "Best" is faulty. The 25p Compressor makes is better than FCP7's deinterlace.

Put the 50i material you wish to double deinterlace to 50p into Compressor. In Inspector, in Video Settings, for Frame Rate select 50. Deselect Interlaced. In Frame Controls, set Output Fields to Progressive. For Deinterlace choose "Better ...". The 50p Compressor makes will have good smoothness because it will use all the fields from the 50i. (I haven't evaluated this pleasantly simple double deinterlace versus the painfully complicated one described in 2012.)

Now open the 50p in Cinema Tools. Conform it to 25 fps. The resulting 25p will play twice as long as when it was 50p.

Your FCP7 timeline will be 25p and in it you'll intercut the normal speed 25p with the slow motion 25p.

Dennis Couzin
Berlin, Germany

for my money, the best de-interlace in FCP is the Nattress smart de-interlace.

for the record, i haven used the compressor one, as i prefer to monitor my results in FCP,
by rendering small, appropriate sections.



for the slo-mo, what ive done in the past is this:

stack 2 version of the clip in FCP.
apply de-interlace to both,
one set to upper, one to lower,
on the top clip, also apply a blink filter, one frame on, one frame off.

you'll have to experiment with the order of upper / lower: it's been a while since i did this, and i've forgotten the fine details.


nick

for the slo-mo, there's also Nattres plug in which i think can do the same thing.
not 100% sure but i think it's his Map Fields plugin.


nick

So for the slowmo stuff, i'll be using AE.
But for the rest, can i just create a 25p FCP project and put the 50i footage in it and just add a deinterlace filter??? Is that right?
thks
Camille

Yes, it's G Map Frames in the Standards Conversion pack. It will take interlaced video, separate out the fields and expand up each field to make a frame, thus turning 50i into 50p (which in a 25fps is 50% slowmo).

Graeme: I guess that's expand up and expand down alternating fields. But there's better deinterlacing available than line doubling, which was my motivation for working out the double deinterlacing routine in 2012. It lets you use the best 50i-to-25p deinterlacing you can find, twice, to do 50i-to-50p. It's too tedious to be practical, but that was its concept.

Now we should evaluate the very simple Compressor method described in the 3rd paragraph in my post above. I've only tried it on this 50i test clip, and it made this 50p. The 50p has smoother sloping edges than line doubling could yield.

Dennis Couzin
Berlin, Germany

Quote
Camille
But for the rest, can i just create a 25p FCP project and put the 50i footage in it and just add a deinterlace filter??? Is that right?

yes, but i would wait till you have finished cutting.



Denis, maybe we're both talking without having the full knowledge.

i blind tested 3 de-intelace filters in FCP, and Graeme's Smart De-interlace came up the best, in picture quality and that included smooth edges

i wasn't comparing it with compressor results.

have you compared compressor results agains any FCP filters?


nick

Nick: my experience is with DV-PAL You've got just 288 lines in a field and bad deinterlacing looks bad. The FCP7 deinterlace filters are garbage. Compressor's "Better (Motion adaptive)" deinterlace is decent. Compressor's "Best (Motion compensated)" deinterlace produces some nasty artefacts.

I'm sure there are better deinterlacing algorithms out there.

Dennis Couzin
Berlin, Germany

hi, Dennis

yeah, my test were on DV PAL, too.
we had to blow up a film for theatrical
Nattress was best, compared against FCP's (worst!) and another 3rd party
tests were done in SD, but i went with the best one.

again, i haven't compared w compressor, maybe one day i will,
but as i said, i prefer to do the work in a timeline where i can make more informed decisions.



cheers,
nick