Another glitch to test

Tim20 wrote on 8/14/2012, 5:50 AM

When I had my ATI card installed I don't remember this happening but if others could try it.

Take a video clip and capture an image then import that image back in.

Do the colors appear more vibrant on the image vs video clip? Also doesn't matter on my system if it is a jpeg or png.

Might not be a big deal for many but when you are working in green screen and need part of a video to become a background plate it is a real pain.

Comments

Dexcon wrote on 8/14/2012, 8:28 AM

Yes, Tim20, I too have experienced a similar problem when using VP11. I created either a jpg or bmp still image from the start or end of, usually, a zoom to help overcome my wobbly handheld camerawork, but only of course when there was no movement in the shot (e.g. people moving about) which would also then be jarringly frozen. There was always a mismatch between the original footage and the still image which I had to correct finely via a combination of contrast, brightness, gamma and gain controls. It's a bit of a nuisance to say the least.
These days, I am using the velocity control to slow the image down to 3 fps and then rapidly rise the velocity to 100% (or vice versa) - and so far, this seems to be a good alternative and without the need for additonal grading.
Cheers

rmack350 wrote on 8/15/2012, 12:58 PM

I don't see color shifts, and I've been using Vegas to capture stills for other projects since version 4. Thousands and thousands of images...(sigh).

One thing you're not saying here is whether you're running Vegas in 8bit or 32-bit color mode. You imply in another thread that you're working in 32-bit float color mode. This may be part of the problem. When 32-bit color was first introduced people used to praise it for exactly what you're describing, not realizing that a color shift was a bad thing if you weren't doing it on purpose. The problem was that in 32-bit mode Vegas assumes some things about color based on your media, and the assumptions can lead to inconsistency. You have to be a lot more careful about mixing media in 32-bit float.

I'm not sure what happens if you're using 32-bit float and also using GPU acceleration. Does Vegas have to convert a frame to 32-float, send it to the filter, convert it to something else when it sends it to the GPU, convert the returned values back to 32-float, send it to the next filter, repeat...? If so...yikes!

There are other things to worry about with Vegas' still frame exports. Basically, it works best if your project is non-interlaced and has a PAR of 1.0. Otherwise, Vegas will automatically and manditorially deinterlace your image which introduces a bit of blur, and it'll apply the project's PAR to the image when it might not be in your interest to do that.

For example, if you export a still from an NTSC DV project Vegas would make it 655x480 (throwing away data). If you then use it as a still frame you're taking what was once 720x480, downsized to 655x480, and then stretched back out to 720x480.

I think this is less of an issue with most or maybe all of the HD project templates but it's not an issue at all if your project has a PAR of 1.0.

Rob

Tim20 wrote on 8/17/2012, 5:56 AM

Tried it in 8 and 32 bit with various footage and it all color shifts. I didn't notice this until recently and after I changed from an ATI to NVidia GPU, but I can't say that is the reason.