Why Format Factory is not on macOS？
Format Factory is a great video converter app on Windows, but it is not released on Mac, if you want to have a similar tool on macOS, there is a great tool on Mac App Store, which is Video Converter X2.
This is a free app on Mac App Store, which support almost all video/audio format. Video Converter X2 provide the quick template to convert the file, this is very helpful if user is not a professional video/audio editor.
The user rating of Video Converter on Mac App Store is 4.9 stars. It is a quite high score as a free apps.
All formats supported
Video Converter X2 support video format: MP4、AVI、3GP、WMV、MKV、VOB、MOV、FLV；audio format: MP3、AC3、FLAC、AAC、M4A、AIFF、WAV etc. It even support QLV, qmc, ncm, VOB etc.
For subtitle file like srt, ssa, ass, Video Converter X2 can load the subtitle into video, and embed the subtitle into the target files.
HD, HDR, Blue ray, all kinds of video format are very big video files. Vidoe Converter X2 can compress the file easily and you can preview the estimated size before the converting. Choose the balance between size and video quality.
Any music format can be converted into mp3, flac, so you can play on a common device.
Video Converter X2 can merge several video files into one single video file with a unique video format.
So yes, there is no Format Factory on macOS, but Video Converter X2 can be a best free alternative to Format Factory.