Recording in MKV, editing in MP4
Screen recorders such as OBS often save to MKV because the file stays readable if the recording crashes partway through. An MP4 that’s cut off mid-write can be unrecoverable. The catch is that video editors, social platforms and phone galleries generally expect MP4.
If your MKV contains H.264 video and AAC audio, ClipFit moves the streams into an MP4 container without touching them. A one-hour recording converts in about the time it takes to read the file.
When re-encoding is needed
MKV can hold almost any codec. Files with VP9, HEVC, Opus or FLAC are re-encoded to H.264 video and AAC audio so the MP4 plays on any device. This takes longer, roughly proportional to the length and resolution of the video.
Only the first video track and first audio track are kept. Subtitles and extra audio tracks, such as a separate microphone track from OBS, are not carried over.
Converting a whole folder of recordings
Select up to 20 MKV files at once and they’ll be converted one after another. Each file gets its own download button as soon as it’s ready, so you can start using the first recordings while the rest finish.
Because nothing is uploaded, large recordings aren’t held back by your internet speed. A gigabyte-scale remux on a slow connection would take far longer to upload to a website than to process locally.
Private by design
ClipFit processes your video inside your browser using FFmpeg compiled to WebAssembly. The file is never uploaded, so there’s no waiting for transfers and no copy left on a server. Once you close the tab, nothing remains.
Questions
Is MKV better quality than MP4?
No. Quality depends on the codec and bitrate inside, not the container. The same H.264 stream looks identical in MKV and MP4.
Does it keep subtitles?
Not currently. Only the main video and audio tracks are converted.
How large an MKV can I convert?
Up to 500 MB per file. For longer recordings, split the file first or remux it with a desktop tool.