Vegas > Gimp > Vegas

Infinite5ths wrote on 8/15/2008, 12:06 PM
I've been searching the forum for a half hour and haven't found the info I need.

The difference between square PAR and NTSC DV or NTSC DV widescreen PARs is clear to me. If I want to take a DV clip from Vegas to Gimp as PNG images, I understand that the PNGs will appear slightly distorted in Gimp due to it's square PAR display.

The "Render Image Sequence" script compensates for the DV>Square PAR difference by automatically converting the SAR.

Debugmode Frameserver leaves the SAR at 720x480, which will be opened by GIMP as if it were a square PAR [i.e. it will be visually distorted].

Is it possible to convert/export from Vegas to a square PAR PNG format [using the Render Image Sequence Script], do the edits in Gimp, then convert back to 720/480 DV without a two-generation conversion quality loss? Or do I just have to get used to editing distorted 720x480 PNGs in Gimp if I want to preserve the original DV quality?

Comments

jetdv wrote on 8/15/2008, 12:20 PM
Using the script is exactly the same as pushing the "Save Snapshot" icon above the preview screen. There's no choice and the image will be converted to the square aspect ratio.
Infinite5ths wrote on 8/15/2008, 12:31 PM
Right...but I do have the option of using the Frameserver instead. Which is one reason why I ask the question above.
rmack350 wrote on 8/15/2008, 4:56 PM
Basically, before photoshop started simulating aspect correction, everyone just lived with the distortion. In SD it wasn't really all that much and there were ways to output from photoshop or Aftereffects to an SD studio monitor to watch what you were doing.

There are some cases where using the script method could be fine because you'd actually end up with more pixels. For NTSC SD, however, the frameserver route would be better because that method doesn't throw out data like the native Vegas frame capture does.

The basic workflow in other NLEs is to export a sequence of images exactly at project size, process them in whatever application you need to use and then either render out from there or reimport the processed frames.

Yes, you might have to view uncorrected frames in the external application and this might cause your squares and circles not to be square and circular.

Rob Mack
Infinite5ths wrote on 8/15/2008, 6:33 PM
OK...well that answers my question.

I have slowly learned that some times it's much easier to compensate mentally [or with a little elbow grease] for a problem than to find a technical solution. This sounds like one of those times. :-)

Thank you for the info.
musicvid10 wrote on 8/15/2008, 9:42 PM
Most snapshot functions inside NLE's capture square pixels.

One exception is the capture utility Scenalyzer Live. In the options is one to save the captured still at square or captured PAR. Saved my tail a few times.

However, if you are trying to match a rendered output, such as for a menu background in DVDA, better to go with a full-res snapshot in Vegas, and then resize it in Photoshop (or Gimp) to 873x480, as an NTSC example. Sometimes, it's important to "preserve the losses."
Infinite5ths wrote on 8/15/2008, 10:14 PM
This is about creating a workflow for FX work in GIMP & Blender: rotoscoping, lighting FX, mattes, 3D CGI for composites, etc.

I'm saving for a nice camera, so I don't want to sink money into After Effects, Boris, etc. Fortunately, I have generous friends with cameras who know how to run them. So I can put some time and money into buying and learning how to use a good camera of my own.

My focus now is to learn and practicing the whole DV production process. A talented 3D animator is working with me in Blender. With the borrowed cams, CGI output, editing/post system, sound/music tools, and several talented friends, I anticipate some exciting work.

That said, FX is the one area where I have no specialized tools - just Blender & GIMP. I need to transfer quality, loss-less frame images between these programs.