macOS has a picture-in-picture mode but only Safari and iTunes can use it. There are some apps like VLC Player that can support it but they need the help of additional apps. If you’re looking for a simpler way to watch videos in Picture-in-picture mode, one where you can play any and all types of media files, including MKV files, give IINA a try. It’a free open-source app with a great picture-in-picture mode.
macOS apps are normally pretty easy to install but IINA relies on CocoaPods to work. CocoaPods manages dependencies for a few different development languages. The average Mac owner may not have it installed. To install it, open Terminal and enter the following command. You will need to provide the admin password to allow CocoaPods to be installed.
sudo gem install cocoapods
Videos in Picture-in-picture mode
Open a video in IINA. Once the video is playing, click the Picture-in-picture mode button next to the Playlist button.
The player will switch to the picture-in-picture mode. The usual rules apply here; you can move the PIP window around anywhere you like and if you close it, the video will return to the main app window.
IINA is no VLC player rival but you will find that it is reasonably well-equipped. You can queue files to play with the playlist feature and tapping the space bar will play/pause whatever is playing. The only area where this app outshines VLC player is in its support for the MKV format.
The MKV format isn’t common so many stock media players can’t play it. The ones that can play MKV files only support a certain codec type which is the same shortcoming that VLC player has. IINA can play an MKV file regardless of the codec because it supports them all. It also supports other common file types so it will take care of most basic media player needs.
IINA isn’t going to run on older versions of macOS. It supports macOS 10.11 and later though the app’s page recommends using 10.14 i.e., Mojave at the very least. It has a dark mode, supports the Touch bar, and can find subtitles for your files.
The app, although open-source, is in active development and you can opt to try its beta or nightly version as well. They’re available for download on the app’s website.