dvd movies
 

why are some movies that i download have the picture squashed together? Is this something to do with compression?

How do i fix this?

A codec issue I think.
Do a searh for codecs on this forum or have a look here:
http://nimo.titanesk.com/

'If' not a codec issue, it could've been poorly encoded. For example, an ntcs video converted over to pal format or vice versa without taking this into consideration. ntsc & pal use different height dimensions & frame rate. Else it might have been widescreen squashed into normal ntsc/pal format. I think they call that letter-boxing when they squeeze a 16:9 aspect video into 4:3 aspect ratio.

is it possible to decode it back to the right dimensions?
How would i go about doing that?

IF that's what the problem is. You'd need an app & encoders that allowed you free choice of dimensions. But once a graphic file has been cahnged, although you might be able to approximate the same original settings, there would be some loss of quality. You could potentially do it with an app like QuickTime Pro using say, divX/mpeg4 codecs. Set for QT format & press Options. Under size you'd click custom. But then you might not even need xtra codecs but the ones QT pro comes with. I have QT Pro & Apple's FCP & DSP so I get some xtra codecs like mpeg2 anyway. I can't remember which codecs you get with QT pro alone. I've also dwnlded 3rd party qt codecs using QT's MIME & update functions. I've also dwnlded some other free ones, namely divx & a couple of others. I suppose it all comes down to what you want to do with it in the end; eg: just watch on comp, or burn to cd or dvd. Best for cd is avi (mpeg4 can be used here) or mpeg. Depending on your burner app, some will convert the video to the required format before burning. eg: mpeg 1 for vcd, mpeg2 for svcd & dvd. Off-hand I don't know what the sizes for widescreen are, there's more than one. I've never worked in it & know little. I think you'd need to reduce the vertical dimension by 25% to 360 lines instead of 480 (w/o cropping.) I don't know much about this area, you can visit: http://www.videohelp.com/ & perhaps http://forum.dvd-guides.com/