View Full Version : Image Super-Sampling?

06-19-2007, 06:11 PM
In the Control Tree under Layer Settings is a check box for "Image Super-Sampling." What is it and what does it do?

06-19-2007, 06:15 PM
Also, just above that is Quality setting (Low, Medium, High). Why would anyone want a Low Quality video?

06-19-2007, 07:18 PM
See ISS in the manual :)

06-19-2007, 07:25 PM
NewTek has the best darn scaling I have ever seen.

06-19-2007, 08:52 PM
You set on low when you are trying to work fast... the just before render switch to high. This is key if you are doing a huge Pan and Scan with large digital photos

06-20-2007, 07:43 AM
Why would anyone want a Low Quality video?

Unless you are scaling, rotating, repositioning, or similarly manipulating the video, switching to high will require extra CPU time to process, for no benefit in image quality. The extra processing in high improves quality when you're doing things like rotating and rescalling.

Mister B.
06-20-2007, 09:31 AM
So switching to high is recommended when converting HDV to widescreen DV, isn't it?


06-20-2007, 11:24 AM
I've always been told that if you're using the render engine in SpeedEDIT to downconvert you don't need to set "high".

Mister B.
06-20-2007, 01:22 PM
I did not try switching to high when doing that but when downscaling HDV to widescreen DV the resulting DV quality is somewhat bad. Bit unsharp, slight color drift and a change in the luma. I hoped switching the layer setting to high at least could make the result sharper.


06-20-2007, 02:59 PM
Did it help?

Thing is, IMHO, it seems silly that one should have to tell a program that is going to RENDER one's output to use high quality, I can't think of ANY reason one wouldn't want that automatically.

I only see the controls as useful if one needs real-time output, in that case it's different, and one sometimes needs to give up quality for speed.

But again, for a render, it makes no sense to me.

Hopefully John Perkins will comment on this.

06-20-2007, 03:36 PM
See ISS in the manual :)

Thanks Steve, now I know there is a manual. I've just been learning by trial and error up to this point. I thought this software was too new and that all there was was the quick start guide.;D

Mister B.
06-20-2007, 03:58 PM
There is no difference when downscaling HDV whether I use "medium" without Super-Sampling or "high" with Super-Sampling turned on.
But I think I was mistaken when talking about the loss of sharpness.

Mister B.
06-20-2007, 04:20 PM
Just to be sure I retested downscaling HDV several times with different footage and always had super-sampling turned off/medium quality. I definately was wrong when I complained about a loss of sharpness. Sharpness is pretty fine!


John Perkins
06-20-2007, 05:40 PM
The quality setting changes two things, image scaling and alpha scaling when the video is not at full project size. (see below)

Low: quick scaling for both
Medium: best quality for image, quick for alpha
High: best for both

So for most cases, the default medium is as good as it gets and much faster. Unless the video is scaled larger/smaller then full screen AND there is an alpha channel, there is no point in turning on high quality. Even then for a lot of footage you may get the same result depending on the shape and smoothness of the alpha channel. Resizing a regular square is dead easy no matter how you do it.

ISS is only really useful for drastic rescaling, such as a web image to video size or making very small picture in pictures. It is not used unless positioning or resizing has been applied.

In SpeedEDIT we added another, better way to deal with video conversion scaling, such as DV footage used full screen in an HDV project.

For all reasonable, normal sizes, we have a huge number of custom resizers that are specifically tailored to only one purpose, i.e. 1440x1080 to 720x480 or 800x600 to 1920x1080, etc. These are very fast and very high quality.

As a rule of thumb, if you have heard the resolution in normal use, it's got a set of custom resizers. For example, 112x700 would not, but 640x480 or 720x486 would.

For "normal" up or down scaling, there is nothing that needs to be done, it is at highest quality already. It is only when you start compositing that these options may be needed.

06-21-2007, 07:13 PM

What about the case when DV footage is in an HDV project and its size has been increased for cropping the edges, or for stabilization? Would ISS help this footage?

John Perkins
06-21-2007, 07:28 PM
That's subjective.

It tends to blur a bit IMHO, but depending on the footage it may.

Paul Lara
06-25-2007, 10:51 AM
Thanks Steve, now I know there is a manual. I've just been learning by trial and error up to this point. I thought this software was too new and that all there was was the quick start guide.;D

The first page of the Quick Start guide offers this advice:
"This guide is intended to familiarize you with the key features and tools, and is not an exhaustive user manual. The user manual is installed as online documentation, and is also available in the SpeedEDIT Documentation folder."

The last page has this little nugget:
"Again, to learn more about any feature within SpeedEDIT, consult the online User Manual in the SpeedEDIT Documentation folder."