You cannot convert a single .ifo file to MP4, or any other video, which is what ifo to mp4 conversion would be. Nonetheless it should be possible to convert whole DVD media (.ifo, .vob etc.) to a single video format (like the MP4), with some dedicated DVD Ripper software specially designed for this job. These programs essentially grab and convert video data in order to save them in one of the multimedia files, often compressed
Open IFO file Open MP4 fileA video ripping tool for Mac
A DVD ripping software package
Older video converter from Wondershare