What “MKV movie” tells you
MKV describes a Matroska container. It can hold video, audio and subtitle tracks, but the extension alone does not tell you the resolution, spoken language or picture quality. Those depend on what was put inside it. Matroska’s format introduction distinguishes a container from a compression codec.
Small files and long films
A 300MB or 700MB label is a size, not a guarantee of a good-looking image. Running time matters: the same amount of data spread over a longer film leaves less data per minute. Multiple soundtracks and different compression choices can also change the total. Compare the edition’s details instead of assuming every small file is 480p or every large file is 4K.
Use the download controls of the viewing app
When a service offers offline viewing, its own app manages the download, storage and expiry. A streamed film does not necessarily have an offline option on every device. MkvKing’s Watch now button opens viewing choices; it does not download an MKV file. My List saves the name of the movie for later, not its video.
Find a title from an old filename
Remove resolution, codec and uploader fragments from the filename. Search the movie name and year, then compare its cast. If you have a series filename, try the name with its season and episode. This is often enough to recover a forgotten film without keeping a confusing collection of old links.