Top 10 MP4 Trimmer for Mac and Windows 1. We have taken the liberty and narrow down to 15 best mp4 trimmer for Mac and Windows pc. If you are still undecided, this is the right article for you. Since they are many free tools that allow you to trim MP4 videos you might get confused on which one to use. In 2019, there are numerous MP4 trimmers that you can purchase, but you can still go for MP4 trimmer free tools available. Which is the best MP4 trimmer for Mac and Windows PC in 2019? Trimming of MP4 video is one of the normal video editing practice as it allows you to remove the unwanted sections of your video and retain the desired portion.