I have a bunch of clips that get imported with an incorrect pixel aspect ratio. The only way I know how to fix it is to go and edit each one by hand, but that is a pain with about 100 clips. Is there a way I can do this all at once?
If you fix it in Pan/Crop by using "stretch to fill frame", you can fix the first one, copy that event, then select the rest, right-mouse button click on one of them, and Paste event attributes. This will copy the Pan/Crop settings from the first to all the others.
I suspect the OP is merely opening his media in the default project template and may be assuming the aspect is wrong because of the preview dimensions.
That is a much more common mistake for a first-time user than incorrectly flagged media aspect, although not impossible. We would need further information to determine which it is.
I'm using clips from two different cameras in a project that is set up for widescreen video. The older camera comes in with a PA of 1.0. The new, widescreen camera comes in with a PA of .909. When I render these clips, they show up as skinny with letterboxing on the right and left. If I change the PA to 1.21, then it fills the frame correctly. I render to a 1.21 widescreen format.
I am having similar problems with two cameras. For clarification, this "aspect ratio" parameter in pan/crop panel, is it the pixel aspect ratio (PAR) or Display aspect ratio (DAR)?