Imported AVI has different dimensions than original file

[MicroImage]

I used Nikon Elements to collect an ND2 file (224 x 696 pixels) using a CCD camera with square pixels. The ND2 file was then saved as an AVI. I used ImageJ to import the uncompressed AVI to do some particle tracking. However, the dimensions in ImageJ are 300 x 696 pixels. What is going on here? Any suggestions?