What's the best way to convert GH animation frames to a video?

I've created a number of BMP frames using the animate feature of grasshopper, but I'd much rather convert the frames to a single video file. I've found a few freeware JPG to Video converters, but I'd first need to convert the BMPs to JPGs. Yet Photoshop wont even open the BMPs created by grasshopper.

Does anyone have an established work-flow for converting the BMP images created by grasshopper into a video file?