Thank you for reaching out and using the Apple Support Communities. We see from your post that your seeking a way to make your MP4 videos viewable on both Mac and Windows PCs. Having that shared compatibility between both operating systems is very important, especially when you want to share to them with others.
By converting, no format limit issue would exist. You can easily watch videos and enjoy audios on iPhone 5, iPad mini, iPod touch, Surface, Galaxy S III, Lumia 920, HTC One, etc. Far more than just a Mac video converter, Leawo Video Converter for Mac also acts as video editor, 2D to 3D converter, media player, screenshot camera, etc. Convert video and audio format to well compatible with Mac OS X (10.11 El Capitan included) For any audio-video files that are not included in the list above, the use of a conversion software like the Aimersoft Video Converter for Mac is necessary to make them playable on a Mac. The Aimersoft software is known to work with all known audio and video files. The best ways to format an external drive for Windows and Mac Compare the different options for formatting an external hard drive to work with Windows and Mac. And, no: the answer isn't always FAT32. How to Change Video Format with UniConverter Step 1. Add video files to video format changer. Open iSkysoft Video Transcoder for Mac after installation. You will see the application window as below. Just locate your files on your Mac and drag and drop it to the application. Multiple video files are.
In this situation, the best way to ensure that both a Mac and a Windows PC can access the videos from the same external device is to make sure the device is in the correct disk format. This article explains how to format a device or disk (e.g. USB flash drive, external hard drive) into the proper format that is accessible by both Mac and Windows computers: Disk Utility 12.x: Format a disk for Windows computers
In regards to your second question, check out this article: If QuickTime Player can‘t open an audio or video file
Please let us know if this resolves your issues.
Sep 1, 2016 10:19 AM