Hello Syaido,
The IMAQ Vision software includes features where you can extract frame image data from avi files. From the image data you have extracted, you can continue and wire them to other VIs to do your analysis. Using this, you will not actually have to convert your avi files to BMPs. I hope that will help you get started with your project. I have attached a file that actually reads a avi file and extracts a frame of your choice out of it. Have a good day.
Ken Sieber
National Instruments Japan