Converting a fullscreen video to widescreen letterbox?

[starwarsgeek]

I did a search in the forums for some info about this, but didn't see any, so please forgive me if this is posted already somewhere. Is there any way for me to take a 4:3 video clip (.avi) that I have and convert it into a 16:9 aspect ratio video? Or is that impossible without "professional" equipment? Or is it just impossible period?

[midnightsun]

yeah it can be done, you will have to pad the picture on its left and right sides in order to make it widescreen. (this is if your intention is to preserve the proportions)

Example:

AVI res:640x480, square pixels (DAR=PAR=1.333=4:3) [DAR means display aspect ratio, PAR means pixel aspect ratio, which for AVI's are coincident because AVI's have square pixels. This may not- and most often is not- true for mpeg's, which contain a display ratio information, called flag, that tells the player what the output aspet ratio (=display aspect ratio) is, regardless of the actual resolution of the movie]

To make it 16:9 you have to fill the screen with black until the ratio of width to height equals 16:9=1.78, that is in this case:

852x480 (rounded to the nearest mod4 number)

This is for AVI output.

If you want mpeg you can do the same, but you will also resize to 720x480 and tell the encoder to do a 16:9 movie.

Then you're done

PS There is a guide written by DJRumpy in the articles section of the forum that explains how resolution, aspect ratios and stuff work. Look it up.

[starwarsgeek]

Thanks for the tip... I'll check out that guide. Does the guide explain how to pad the picture on the left and right as well?