768×576 Clip?

Stuart Robinson wrote on 8/27/2006, 10:12 AM
Next problem is a clip that's been provided as an AVI and is actually 768×576. This is the square-pixel equivalent of 720×576 PAL.

The footage itself is anamorphic, so should ultimately be displayed at 1024×576 (or 16:9 on-screen).

I'm having a few problems with this clip in Vegas, I'm getting black bars top and bottom, or when using the PAL 16:9 properties profile, black bars to the left and right. Setting the source ratio as 1.00 (ie. square pixel) doesn't seem to help.

I wondered if anyone had any pointers as to what properties to use to get this clip to output as anamorphic 16:9 PAL encoded as 720×576?

Thanks!

Comments

Spot|DSE wrote on 8/27/2006, 10:44 AM
Are you displeased with the Pan/Crop means of bringing this to full-frame? I'm gathering that you've converted the pixel aspect of the clip to .9 already, since you mention "Setting the source ratio as 1.00 (ie. square pixel) doesn't seem to help."
Stuart Robinson wrote on 8/27/2006, 11:56 AM
Thanks for the reply.

>Are you displeased with the Pan/Crop means of bringing this to full-frame?<

I'd rather use all the resolution available if possible, the clip isn't the greatest quality so rather than expanding the frame or cropping elements, making it smaller and living with some letterbox areas top and bottom would be preferable.

>I'm gathering that you've converted the pixel aspect of the clip to .9 already...<

Actually no, the clip still has square pixels. How does one do that, is it a case of manually entering a value in the clip or project properties field? I've tried 0.9 in a few places and there are still black bars (sides or top/bottom).

Marco. wrote on 8/27/2006, 1:37 PM
Vegas expects the square pixel equivalent of a DV PAL video to be 787x576.

So try applying a pixel aspect ratio of 1.0247 to your 768x576. If my math is right this should correct the proportion.

Though sometimes - dependend on the source - it is better to leave the black borders and to keep the geometrie this way.

Marco

Edit:
I oversaw your file should have 16:9 properties. What I wrote above would (hopefully) get you a correct 4:3 result.
Try a PAR of 1,3646 then for your 16:9 file. Not sure if I'm right here.

Stuart Robinson wrote on 8/27/2006, 2:38 PM
Marco,

>So try applying a pixel aspect ratio of 1.0247 to your 768x576. If my math is right this should correct the proportion.<

Thank you, that has done the trick, having set the clip to 1.0247 the preview in Vegas is now using the entire frame.

My next problem is how to render this clip as an MPEG-2 file, the project settings are PAL DV (pixel ratio of 1.0926) and I'm using the DVD Architect PAL Widescreen profile, but the rendered file has huge black bars left/right so it's assuming the image area is the equivalent of 4:3.

I can render using the 4:3 DVDA profile and the result looks OK, but I'll have to go through the file and change the MPEG-2 flags to 16:9 and that seems like a bit of a bodge.
Marco. wrote on 8/28/2006, 2:15 AM
Try setting your project to widescreen properties and modify the PAR of your clips to 1,3646.

If you've set your internal preview to "Simulate Device Aspect Ratio" (by right-click) your video should look o.k. now - and in proper 16:9.

If you render now with the DVD Architect PAL Widescreen profile your result should be fine. Presupposed my math was correct again ...

Marco