dvx100 and blender

Hi folks,

I’m trying to composite some work in blender with some footage from a dvx100 in vegas video. My problem is that I can not get the size/aspect/pixel size to match.

The original dv video is pixel aspect ratio 0.9091 (NTSC DV), 720 x 480 and progressive (non interlaced) with a 23.976 (IVTC Film) frame rate.

I have tried using the ntsc preset with its AspX 10 and AspY 11 and with a 1 to 1 ratio. Both, however, when brought into vegas appear to be too short.

I have searched other posts for a solution and cannot find one; so any help will be much appreciated.

Try rendering it with square pixels (AspX & Y both set to the same value… 10 should be okay). Just make sure the resolution is still 720x480.

EDIT: I’m an idiot. You said you already tried square pixels. The standard aspect for NTSC is 4:3… so try those as your AspX and AspY values.

thanks for the suggest Fweeb. I measured the frame from vegas and it turns out they are 654 x 480, so setting blender to render this with a 1:1 AspX and Y works.

I’m not sure why the footage isn’t 720 x 480 but whatever works, right?

Blender has settings to render your footage correctly. I don’t know where you’re getting that 0.9091 number from, just use .9 in future computations. In Blender however just use the NTSC render setting, it’s all set up already. Just make sure you’re progressive to match your footage.

I don’t think you have to worry about that 23.976 rate either Again, where are you getting these numbers? 23.976 is unnecessary. Just render at 24 fps and import into Vegas.

If for any reason you’re still getting aspect ratio problems, render your scenes at 720x540 (with your aspect XY at 1:1) and tell Vegas you’re importing square pixel data. Vegas should correctly adjust it to non-square.

When mixing live footage with CG, you should emulate video noise (assuming of course, you’ve rendered photorealistic CG, and it’s worth the process:-). I’m not sure how to do this within Blender, but if you have sufficient compositing capability in Vegas (and I’ve read that there is), synthesize a color noise layer using a 50% gray still image at a noise level consistant with your video noise (inother words, add a noise filter to your 50% still layer and adjust to match). Give it a mild blur to match your video noise fiffusion, then apply the layer with an OVERLAY transform on your CG footage. Adjust the noise layer density to match the video noise.

Hopefully all that made sense. :slight_smile:

Just a blind-ass guess, but Vegas probably adjusts the video to square pixels so it displays with proper proportion on your computer monitor. So… it’s still working with images at 720x480, but you’re working in the smaller area.

That’s just my guess, though.

Hi !

The pixel aspect is a problem, when you try to match the TV or DVD standards, because these standards seems no to be standard !

I explain a little :

I want to render a movie with Blender, in Pal 25fps 1024 x 576.
I use Pal, because I’m french, and the European standard is Pal.

I have extracted some pictures with Photoshop, from several commercial DVD : Terminator 2, and Shrek 2 for example. I have selected the area around the image :

I have noticed that the height of the 2 black strips was very different from a DVD to an other one.

This means that the really usefull number of lines contained in the picture is not the same for all DVD.

At first sight, It seems to vary from 420 to 525, and I do not know if there is a rule. It may be variable according to original format of the camera.

This means that the initial picture is more or less stretched to fit in a 16/9 picture format, without taking care of a particular ratio of the image.

In these conditions, it is not easy to chose a pixel aspect !

Philippe.

1024x576?

That’s your problem right there. D-1 PAL is 720x576. Measuring the letterboxing on DVD’s isn’t going to help you much at all, because the final resolution is going to be either PAL or NTSC to play on a television. “Standard” film aspect is supposed to be 16:9, but that’s not hard and fast, as you noticed.

A quick google will give you this site, which is pretty informational. Most DV and miniDV cameras that I know about shoot to a D-1 standard (NTSC & PAL), but this site should explain most of this for you.