Julieanne Kost | Principal Evangelist at Adobe Systemshttp://blogs.adobe.com/jkost/lightroom-training-videos
Working with video in the Library module of Lightroom Classic offers some simple tools for previewing, setting poster frames, and creating stills from frames that can be exported to the Develop module. Lightroom Classic imports many common digital video files from digital still cameras. You can preview video clips in the Loupe view of the Library module, scrub videos, set poster frames, and more.
To know about the supported video formats, see Supported video file formats in Lightroom Classic.
Note: Lightroom Classic stacks the capture frame with the video clip. The stack is only visible when viewing All Photographs or the folder containing the clip. If you captured the frame while in a collection, the frame will be added to the collection but the stack will only be visible when in All Photographs or the containing folder. Neither the frame nor the stack will be visible when viewing smart collections, published collections, Quick Collection, Previous Import, or other built-in collections.
You cannot open videos directly from Lightroom Classic into Photoshop.
If you edit the metadata of a video file in the Library module, the changes are stored in the Lightroom Classic catalog. The information is not available to other applications. You cannot see or edit the video camera’s capture time in Lightroom Classic.