No limit on filesize. For some reason your machine cannot handle the avi.
The mp4 should look the same as the avi.
Make sure you have a dedicated seperate disk for video.
As Ann says, there is no file size limit (assuming your hardware can handle it) -- but converting video is never a good idea.
I recommend you use the original video, directly from the camcorder.
If your computer is properly configured and you have the latest version Quicktime, you should be able to edit it in Premiere Elements 12.
>recommend you use the original video, directly from the camcorder
Does that mean that version 12 will now work with Gopro video without the conversion that Gopro recommends?
-below says Mac (Win process should be the same) but even GoPro says to convert to edit
-use to convert http://gopro.com/software-app/cineform-studio/
There is no limit on the file size. Regarding the poor quality of Mp4 in PRE12:
1. Make sure you have selected correct project preset (most of the time PRE automatically selects the correct project preset for you.).
2. Right click on the source monitor in PRE and click on Playback Quality-->Highest
3. In case you are getting poor quality after rendering the timeline try the following:
a. Go to Edit--> Preferences-->General and change Timeline Render Quality from "Draft Quality" to "High Quality"
I have no problems editing GoPro footage in its native form.