Footage shot in 60i to be slowed down and view on internet at DVinfo.net

Brendan Pyatt · August 22nd, 2008, 03:41 AM

Hi,

I have many clips shot in 60i which I would like to slow down and then distribute on the internet.

I have been told that I should convert it to progressive and then use a plug-in like Twixtor.

What is an easy way of converting 60i into progressive?

I am using FCP Studio 2.

Thanks.

Giroud Francois · August 22nd, 2008, 03:50 AM

if your plan is to use full size video, you need to deinterlace.
if you will display smaller size, the easiest way is to keep only on frame (dividing video height by 2).
if the size is neither full size nor half size but in between, you have to deinterlace first, then resize.

Brendan Pyatt · August 22nd, 2008, 04:07 AM

Quote:

Originally Posted by Giroud Francois

if you will display smaller size, the easiest way is to keep only on frame (dividing video height by 2).

i think it will be smaller than half size - around the size of a youtube video window.

what do you mean by 'keep only on frame'

whats the best way to de-interlace?

there seems to be quite a few tools for doing this - can I do it in FCP or is the a better easier way?

Furthermore, how do tools like like Twixtor help with slo-mo?

Giroud Francois · August 22nd, 2008, 07:36 AM

if it is smaller than half size, you do not need to deinterlace.
first make it half size, then resize smaller.
Usually when you make a video half size , the computer simply discard one frame, so you get it "deinterlaced"

Brendan Pyatt · August 22nd, 2008, 01:03 PM

thanks!

I am not sure i really understand this though....

I thought progressive was a full frame and interlaced a half frame (alternate lines).

My understanding was that to get a decent picture on the internet - to be view on computer screens a progressive image was better as tv de-interlace and computer screens don't.

Giroud Francois · August 22nd, 2008, 03:46 PM

interlaced picture creates a problem because 2 frames of an interlaced picture are not taken at the same time.
So if the subject is not moving, the lines (even and odd) stack fine and you will not see any trouble with the picture.
if the subject is moving fast , you can imagine that a frame contains a totally different picture than the next frame (at one frame subject can be at left, and in the next frame subject moved to the right . When you mix them to rebuild the picture, you see the problem.
progressive screens are displaying both frames at the same time, so they shows this "interlaced artifact".
TV screens are sending one frame, then the other one, so you do not see the problem.

When resizing video the process is the same, picture is first rebuild, then pixel are resampled to the target size. If picture is interlaced, you could get 3 lines from a frame, then 3 lines from the other frame. when rebuilding the picture, the artifact is there.

dividing a picture by 2 is the only case when resizing is ok for interlaced picture.
because taking one line on two is the same than discarding one frame.

August 22nd, 2008, 03:41 AM	#1
Brendan Pyatt Regular Crew Join Date: Sep 2005 Location: Southampton UK Posts: 165	Footage shot in 60i to be slowed down and view on internet Hi, I have many clips shot in 60i which I would like to slow down and then distribute on the internet. I have been told that I should convert it to progressive and then use a plug-in like Twixtor. What is an easy way of converting 60i into progressive? I am using FCP Studio 2. Thanks.

August 22nd, 2008, 03:50 AM	#2
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	if your plan is to use full size video, you need to deinterlace. if you will display smaller size, the easiest way is to keep only on frame (dividing video height by 2). if the size is neither full size nor half size but in between, you have to deinterlace first, then resize.

August 22nd, 2008, 07:36 AM	#4
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	if it is smaller than half size, you do not need to deinterlace. first make it half size, then resize smaller. Usually when you make a video half size , the computer simply discard one frame, so you get it "deinterlaced"

August 22nd, 2008, 01:03 PM	#5
Brendan Pyatt Regular Crew Join Date: Sep 2005 Location: Southampton UK Posts: 165	thanks! I am not sure i really understand this though.... I thought progressive was a full frame and interlaced a half frame (alternate lines). My understanding was that to get a decent picture on the internet - to be view on computer screens a progressive image was better as tv de-interlace and computer screens don't.

August 22nd, 2008, 03:46 PM	#6
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	interlaced picture creates a problem because 2 frames of an interlaced picture are not taken at the same time. So if the subject is not moving, the lines (even and odd) stack fine and you will not see any trouble with the picture. if the subject is moving fast , you can imagine that a frame contains a totally different picture than the next frame (at one frame subject can be at left, and in the next frame subject moved to the right . When you mix them to rebuild the picture, you see the problem. progressive screens are displaying both frames at the same time, so they shows this "interlaced artifact". TV screens are sending one frame, then the other one, so you do not see the problem. When resizing video the process is the same, picture is first rebuild, then pixel are resampled to the target size. If picture is interlaced, you could get 3 lines from a frame, then 3 lines from the other frame. when rebuilding the picture, the artifact is there. dividing a picture by 2 is the only case when resizing is ok for interlaced picture. because taking one line on two is the same than discarding one frame.