Capture Aspect Ratio Question

[stevendm]

I was under the impression that a normal NTSC tv signal is broadcast with a 4:3 aspect ratio. This is great as 640 x 480 is 4:3. What happens to this aspect ration when I convert it in DVD Workshop for DVD-R? The outgoing video file is 720 x 480.

Is the picture stretched horizontally to fit 720 pixels vertically? If so, this is not 4:3 anymore.

Should I do some avisynth processing so that the visible portion of the video file is 640x480 with black borders on the sides?

What gives here? Am I just thinking wrong here?

Thanks for the advice.

Steven

[Dodzzz]

You shouldn't edit anything, the final output will be 720 x 480, but it will be displayed as 4:3 automatically by DVD players if the file was encoded with 4:3 Display flag.

[stevendm]

That make sense. Now I will ask the original question that brought me to the one I asked above.

I want to shrink down the image to compensate for apparent overscan problems during capture. I think that by shrinking down the image by about 5% I can see the same amount of screen real estate from my DVD that I did when I watched the original broadcast. I am judging this by looking at the relative position of the TV Land logo to the botom-right corner of my TV.

I know that I cannot take off the same number of pixels on each side. That will stretch out the picture. Do I take 1.5 times the amount form the sides as I do from the top (720 / 480)? Do I take 1.33 time the amount from the sides (640 / 480)?

I know if I leave the file alone and encode it the logo is moved down and to the right a noticeable amount.

Or is there a way to adjust the amount of captured vide that my ATI 8500DV will capture? This wil make everything a moot point. I am capturing at 352 x 480 with a PicVideo MJPEG at q19.

Thanks

Steven