VOBs, or Video Object files, are DVD movie files encoded with MPEG video data, according to PC Magazine. Converting VOB files to MP4s (MPEG-4s) is not difficult since they are compatible formats; however, one must find a program that can read and convert VOB files and/or whole DVDs. HandBrake is a free program for download that deals specifically with ripping and converting DVD and VOB files to a number of different formats, including MP4s. Note that converting VOB files to MP4s may result in loss of audio/video quality, due to compression standards.
Click the main "Source" button in the upper left-hand corner of the screen.
Use the finder window to locate your VOB files. Open them in HandBrake.
If you are converting off a DVD, insert your DVD and wait for HandBrake to recognize the data. If it doesn't recognize it after a few moments, click "Source" to locate the DVD files manually. Choose your chapter or track selections.
Click the "Presets" or "Toggle Presets" button to open a side menu of preset options.
Choose one of the "iPod" presets. These are formatted for MP4 conversions.
Choose your "Destination" output by clicking the "Browse" icon. Rename your file, if needed.
Click "Start" to begin the conversion process. Depending on your files' sizes; this will take several minutes.