People often find that they need help finding the best media player for themselves and use several simultaneously. This is especially common for people who have just switched from Windows to Mac. On Windows, they used only one player, MPlayer for Windows, this media video and audio player for the Windows platform, which supports many media formats. While macOS owners, for the first time, need help understanding how to use this system after Windows, and when they start figuring it out, they spend some time searching for the perfect video/audio player.  

The best option for macOS operating system. 

Many players have basic features that just about everyone has.  

Elmedia Player is a handy and functional player supporting over 500 formats and devices. You can add files one by one or at once in a folder from your computer and download videos to the program directly from the Internet or a DVD. In addition to video and audio conversion, the program provides basic editing features: adding visual effects, trimming, and gluing fragments into one clip.

A distinctive advantage of the media player is built-in export configurations optimized for viewing on a particular device. So you can save your movie on a cell phone, tablet, or even a game console without losing quality. The list of supported devices is constantly updated. I do not know open avi on mac, so I recommend you use Elmedia Player. 

The best option for Windows. 

This is the best version of Elmedia Player for Windows. Despite the large number of files that can be played with the standard media player Windows Media Player, the player plays with third-party players such as Media Player Classic. 

It is an extremely lightweight open-source AVI multimedia player for the Windows operating system. It supports displaying all common video and audio formats. Thanks to the open source, the application has no ads and no built-in spyware that can collect data about the user. 

A distinctive feature of the utility is the playback of FLV files with the ability to rewind. It is well-optimized to work on older computers. It is possible to play clips by link, add subtitles for movies and automatically search for them on various resources on the web. 

The program is fully translated into Russian, although the project's official website remains only in English. The development of the product was stopped in 2017. 

Advantages: 

• free 
• open source - no malware 
• Availability of a large number of languages. 

Disadvantages: 

• outdated interface 
• no cross-platform development and technical support officially discontinued