Lightroom Video Support

Some video file formats—such as MOV and AVI denote container file formats rather than denoting specific video data formats. Container files can contain data encoded using various compression and encoding schemes. Lightroom can import these container files, but the ability to import the data that they contain depends on the codecs (specifically, decoders) installed.

By installing more codecs, you can extend the ability of Lightroom to import/play some of the video file types. Many codecs installed into the operating system (Windows or macOS) work as a component inside the QuickTime or Video for Windows formats. Contact the manufacturer of your hardware or software for more information about codecs that work with the files that your specific devices or applications create.

Source: https://helpx.adobe.com/lightroom/kb/video-support-lightroom.html