Convert MKV to MP4
MKV recordings and videos that play on phones, TVs and editors.
Convert MKV videos to MP4 to play them on a phone, a TV or a games console, open them in iMovie or another editor, or upload them to a website that only accepts MP4. Most MKV files already contain H.264 video, so the conversion is usually instant and loses no quality.
How to convert MKV to MP4
- Select your MKV video (up to 100 MB).
- Click “Convert to MP4”.
- Wait a few seconds while we prepare the MP4.
- Download the MP4.
Why convert MKV to MP4
MKV (Matroska) is a very flexible container: it can hold several audio tracks, subtitles and chapters, and it survives crashes during recording, which is why many people set OBS Studio to record in MKV. Its weak point is compatibility: VLC and most computers play it, but many phones, TVs, consoles, editing programs and websites don’t.
Instant when possible
If the image of your MKV is in H.264, which is the case for most recordings and downloads, we copy it as it is into the MP4: no re-encoding, no quality loss and almost no waiting. If it is in another codec (HEVC, VP9, AV1), we re-encode it in H.264.
The sound is copied if it is already AAC; otherwise (Opus, AC-3, FLAC…) it is converted to AAC, which every device plays.
What isn’t carried over
- Only the first audio track: if the MKV has several languages or a commentary track, the MP4 keeps the first one.
- No subtitles or chapters: if you need the subtitles, keep the MKV or the separate subtitle file.
- No metadata: title, tags and dates are left out.
Limitations
- One video at a time, up to 100 MB. If the video has to be re-encoded, it can’t be very long: the message will tell you the maximum.
- If you record with OBS, it can do this conversion itself for your own recordings: File › Remux Recordings.
- To make an animation from a clip instead, use MKV to GIF.
Frequently asked questions
Does converting MKV to MP4 lose quality?
Not if the MKV is in H.264: we copy the image without touching it. Only when it is in another codec, such as HEVC or VP9, do we re-encode it, with a very small loss that is hard to notice.
Why doesn’t my TV play MKV files?
Many TVs, consoles and phones only support MP4, or they open the MKV but not the codec of its sound or image. An MP4 in H.264 with AAC sound plays on practically all of them.
Are the subtitles of the MKV kept?
No. The MP4 we create only carries the image and the first audio track. If you need subtitles, use the MKV with a player such as VLC, or keep the subtitle file and load it alongside the MP4.
Is it better to record in MKV or MP4 in OBS?
MKV is safer: if OBS or the computer crashes, the recording is still usable, while an unfinished MP4 can be lost. That is why it is common to record in MKV and convert to MP4 afterwards.