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Cropping in Vegas (or other software)

boon23 said:
Aspect ratio is maths, nothing else than that.
Digital movies work with a trick to create widescreen by stretching pixels.
So the width with which you need to calculate for NTSC is 854. Yet what you use is 720. The height has to be calculated as if you used 854 width.
For example:
Your video is 2.35:1.
for an avi (no pixel stretch) the size would be: 854x363 or 720x306.
For your 16:9 mpg the size would be: 720x363.
So you have the usual 720 width, but will see a stretched height. The widescreen setting will correct that.
Click to expand...

Thanks, boon. I understood about anamorphic already, but this helps me to understand what Throw told me to do when making the MP4. The program doesn't see the black bars does it?

I still don't know how to input any of this into Virtualdubmod MPEG-2 though, unless you can only do it when you frameserve?
 
for virtualdub you also need to set the black bars to get back to the full 720x480 for NTSC.
as for my example:
720x363 is the size for the video
Using the resize filter you set this size and use "expand frame and letterbox image" using 720 for width and 480 for height.
These are the black bars.
From this you can either export to lagarith avi or frameserve. Both options are good for the final mpg rendering.
 
boon23 said:
for virtualdub you also need to set the black bars to get back to the full 720x480 for NTSC.
as for my example:
720x363 is the size for the video
Using the resize filter you set this size and use "expand frame and letterbox image" using 720 for width and 480 for height.
These are the black bars.
From this you can either export to lagarith avi or frameserve. Both options are good for the final mpg rendering.
Click to expand...

Drat! I didn't tick the "expand frame and letterbox image" option!

This is what I did.

Nulltransform and crop to 710x480.
Resize using lanczos3 to 720x480.
Used various other filters to correct colour, flicker etc.
Frameserve to CCE
Select 16:9 in the settings option and exported.

The clips I exported do read as 720x480 in Womble and VLC and look perfect. Does this really mean I have to do it all over again? :cry:

Sorry for being extremely thick about all this. Everytime I think I've understood everything, something else crops up.
 
Well, it's been a long time since this thread was posted in, but I've recently found out a few things I didn't know about the situation elbarto1 described. It has been bothering me for some time.

Apparently, the thin black bars that are sometimes visible on the sides of a DVD transfer are meant to be there. This is because of nominal analogue blanking (NAB). http://en.wikipedia.org/wiki/Nominal_analogue_blanking

Basically, even if you have a modern television capable of an exact/just/1:1 scan, you should use it primarily for blu-ray/HD DVD. DVDs encoded with NAB should be viewed on wide/16:9 mode, whatever your TV calls it, not exact scan, because the 8 pixels on the left and right (or 9 for PAL) are considered junk and do not form part of the correct aspect ratio for the movie. In fact, on exact scan, the picture is slightly off from its correct proportions, though the result might not be noticeable. This is why there are often black pixels, or junk image pixels, at the sides. They are not meant to be seen and ought not to be seen; consequently, their presence is not evidence of a bad transfer.

This affects how I view certain source material, because I have a number of DVD transfers that, when viewed on exact scan, seem at first to have differences in the sides. I have thought until recently that these transfers exhibited a problem that needed correcting. For example, I resized my two LOTM transfers to match because of this. It turns out that I need not have bothered to resize - though cropping new borders was still a good idea, and I learnt a great deal in doing it that I have since applied to other situations.

If the differences in the sides of transfers still bother people,they could crop eight pixels from both sides to make them match and author a 704x480 DVD, which is apparently valid in the DVD standard. Alternatively, one could pad both sides with 8 pixels of black bars and author a 720x480 DVD as usual, which is probably what I shall do when I redo my LOTM edit at some point.

A number of modern transfers do seem to ignore the NAB convention, such as the Star Wars 2004 Special Editions. Transfers that do exhibit analogue blanking are not incorrect though.
 
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