Here's the quick background of what I'm doing. I have some video shot with Canon HF100 (AVCHD 1920x1080, 60i) and some video shot with an older Sony DVD camera (mpeg-2 720x480, 60i). I'm combining them into one project in Vegas Pro 8.0b, and rendering to 720x480, 60i video (using Render As... / Mpeg-2 / NTSC DVD template).

Now, this part works like a charm, everything renders and looks great. Now, the HD video is 16:9, so it has black bars at the top and bottom in this final render, as expected. Fixing this is where I run into problems...

I used the "pan/crop" option to crop some of the sides of the HD video to get the aspect ratio to match the 720x480 video. I selected the "4:3 standard TV" preset, and then expanded it a little bit on the sides to get the proper aspect. When previewing this, everything looks great.

When I now render this video again (using the same options), the resized HD video now has very exaggerated wavy artifacts on the edges of moving objects. It's similar to playing interlaced video without de-interlacing, except the wave artifacts are at least 10-20 pixels high, not a single line as with the "combing" effect.

I'm totally puzzled here, I don't have enough video knowledge to even guess what is going on here -- the preview is fine, render without cropping is fine, but render with cropping has wavy artifcats.

Playing with different aspect ratios didn't make a difference -- choosing 4:3 preset and just having some black bars on the sides also produces the wavy artifacts -- it seems like any resizing of the original AVCHD does this.

Does anyone have any ideas or thoughts on what is happening here?