I have a number of .iso video files 4.7GB is size. I'd like to convert them to perhaps .avi or .mpg4 format to reduce the size and for playing on equipment that likes files not DVDs. Running Linux Mint 17.1 with Mate Desktop. Is there software to do this directly? Do I need to firstly make DVDs then use a ripper? Any suggestions on which software to use?
An iso file of 4.7GB is no video file, but a DVD Image file. You should be able to mount the iso
mount -o loop ISOFILE MOUNTPOINT
You will still have to extract the AV Information, that is organized in chapters on a DVD and create a video stream from that.
It will be some research and work, but the best results can be achieved with avconv.