Question for WorkPrinter/Mac users (frame blending)

Post by **brightlight** » Thu Jan 24, 2008 10:08 am

When changing the playback speed in FCP, does anyone check off the frame blending mode?? I tried this on a sample clip, and the image is clearer (when scrubbing from frame to frame), but the playback seems slightly choppy, and it seems like it's playing a little slower. Maybe my eye has adjusted to using the frame blending mode, but should I not be using it at all?

Post by **filman** » Thu Jan 24, 2008 9:49 pm

it depends from which effect you want to obtain : if you click on "frame blending" the computer will recompute the new intermediate frames ( if you slow down) and the images will be softer because the frames are averaged together. if you uncheck, the computer simply cuts ( if you speed up) or repeats the int. frames (and so you will avoid rendering) and the images will be as clear as in origin. hope to be helpful
regards

Post by **johnnhud** » Thu Jan 24, 2008 10:41 pm

If you want a true 1 to 1 copy of your transferred film, do NOT check Frame Blending. The beauty of a WorkPrinter is it's ability to scan fully progressive images (even with a non-progressive camera) and assign 1 frame of film to 1 frame of video.

By enabling Frame Blending your are essentially doing just that. Blending two frames together to create a third, non progressive frame. While it will appear to make your clips run smoother, it will also soften them considerably.

Remember that most older footage WAS a little choppy because the cameras ran at 18 Fps or even slower (9fps). If your transferring 24fps footage, you wont notice the choppiness so much.

Post by **brightlight** » Thu Jan 24, 2008 10:45 pm

Thanks, I'm starting to see the difference between the two. The big difference is when I freeze on one frame, and if the frame blending is on, you can see the interlaced "artifacting", whereas I just get a still of the whole frame when it's not checked. Plus as the guy above mentioned, I don't have to render when I change the playback speed.

Post by **Dave Anderson** » Sun Feb 03, 2008 3:04 am

I am wondering the same thing. I used to frame-blend (interlace) everything via Dodcap for smoother playback on standard TV's. Am I better off keeping everything Progressive now (especially with the advent of the newer progressive scan TV's?)

Johnhud, sounds like you'd recommend keeping it off for everything?

Thanks.

Post by **Chris-B** » Sun Feb 03, 2008 2:01 pm

I guess it is up to personal preference.

I prefer non blended for film shot at 18fps, for PAL. (I've never used an NTSC system). I have found that many people in North America prefer blended for film shot at 18fps for NTSC.

Maybe it is something to do with the 18fps converted to 30fps (NTSC) compared to 18fps converted to 25fps (PAL), so more duplicated frames with NTSC that may give jumpier playback - Just a guess.

I just prefer the slightly jumpier clear image, rather than the smooth slightly blurry one.

I think that the frame blending blur always looks worst on a PC monitor than on a normal CRT TV, same goes for the jerky unblended stuff it looks a lot smoother on a TV (PAL).

Try a clip both blended and unblended and burn a DVD, or dump to DV, and watch it on a CRT TV to see which one you prefer.

Not sure of the results with a Plasma or LCD TV.

Luckily in PAL countries we have the option to shoot at 24/25fps to avoid this issue altogether, there are no cameras I know of that shoot 29.97/30fps ( I can image there are some out there that do 30 or even 32fps)

Just my thoughts on the issue,
Chris.

Post by **johnnhud** » Mon Feb 04, 2008 7:31 pm

Dave Anderson wrote:I am wondering the same thing. I used to frame-blend (interlace) everything via Dodcap for smoother playback on standard TV's. Am I better off keeping everything Progressive now (especially with the advent of the newer progressive scan TV's?)

Johnhud, sounds like you'd recommend keeping it off for everything?

Thanks.

Let me clarify. I would only recommend keeping Frame blending off if you are concerned about making a true 1 to 1 copy of your film. If you do that then your copy will be no more jumpy or choppy than the original source footage. If you desire to smooth out the playback of the film, then adding frames is the solution. However you loose your "progressive" image for one that is of lower quality.

For example. Frame Blending off would result in the following playback

Frame 1, 2, 3, 4, 5, 6, 7, 8 ,9, 10, 11, 12, 13, 14, 15, 16, 17, 18

Frame Blending ON would result in this

Frame 1, 1-2, 2, 2-3, 3, 3-4, 4 4-5, 5, 5-6, 6 6-7, 7 7-8, 8 8-9, 9, 9-10, 10....etc...

When the frames are blended it takes frame 1 and 2 and creates a blended frame of 1-2. Frame 1 fills the Odd scan lines, while frame 2 fills the even scan lines, thus destroying the progressive image but also giving the illusion of smoother playback.

Here is a video image that compares interlaced to progressive.

I would never say "Never use frame blending" because it depends on what result your looking for. However the best way to add additional frames of footage without destroying the original source is to use a program that builds frames using Optical Flow, like Shake. But this would also be VERY impractical for general transfer issues.

-Johnnhud

Post by **brightlight** » Mon Feb 04, 2008 8:29 pm

I am doing all my projects with the frame blending mode switched off now. I think one of the main points of the WprkPrinter is that it is a progressive scan transfer, so the output should be progressive as well. I also agree that the two modes look quite different when viewing them through a computer monitor or a SD TV.

As John mentioned in his post, the big difference is when you take a still image of a single frame. No interlacing or artifacting when the frames aren't blended.