If you need to perform this conversion yourself without losing quality, tools like are the gold standard. A simple command can "remux" the video (changing the container without re-encoding the actual video data): ffmpeg -i input.mkv -codec copy output.mp4
This process is nearly instantaneous because it doesn't "re-render" the video; it just moves it into a new "box". 11588.mkv.mp4
: MP4 is the industry standard for hardware-accelerated decoding, meaning it uses less battery on your phone or laptop. How to Convert Your Own Files If you need to perform this conversion yourself