Convert MKV to MP4

MKV to MP4の使い方

1. 1

   Add MKV files

   Drop up to 3 .mkv videos — recordings from OBS, downloads, ripped discs — of up to 500 MB and 10 minutes each.

2. 2

   Check what will happen

   Fast · no quality loss means H.264 or HEVC video moves over as is; Re-encode means the video or the sound needs converting for MP4.

3. 3

   Adjust quality for re-encodes

   High is preselected; Balanced or Small and a lower resolution make re-encoded files lighter.

4. 4

   Convert and save

   Press Convert to MP4 and download each name.mp4 or the whole batch as a ZIP.

MKV to MP4 について

MKV (Matroska) is a flexible open container: it can hold almost any video and audio codec, several audio languages, subtitle tracks, chapters and attachments. That flexibility is also why phones, smart TVs, iMovie, Premiere and social networks often refuse it, while they all accept MP4. Converting MKV to MP4 is mostly a change of container.

When the MKV holds H.264 or HEVC video, which is the case for OBS recordings and most downloads, the video is copied into the MP4 without re-encoding. AAC or MP3 audio is copied too, so the job takes seconds and nothing changes in quality. Sound in formats an MP4 player can't rely on — AC-3, E-AC-3 and DTS from films, Opus, Vorbis or FLAC from open-source tools — is converted to AAC at 160 kbps while the picture is still copied. Video in VP9, AV1 or older MPEG-4 is re-encoded to H.264, which plays on every phone and TV; that is the slow case.

MP4 can't hold everything MKV can, so only the first video and the first audio track come across. Subtitle tracks, extra languages, chapters and attached fonts are left behind; to keep subtitles visible, add them back with the Add subtitles tool, which can burn them in or put them in a track MP4 supports. Files larger than 500 MB or longer than 10 minutes need Pro.

MKV to MP4：よくある質問