Although MPEG4 and MP4 are different, it is easy to convert MPEG to MP4 or vice versa with the best free video converter. But from the angle of container format vs filename extension format, I think you can gain a better understanding through MKV vs MP4. Which is better MP4 or MPEG4? Both of them have their pros and cons.
But MP4 is the format of most streaming videos on the Internet which is easily more playable on mobile devices like Android, iPad, iPhone than MPEG format. You can use MPEG4 format to save subtitles, images, videos, and audio. The former is a digital multimedia container format, while MP4 is a filename extension. How do I convert iMovie to MP4 with just one-click?