What does MKV to MP4 Converter do?
MKV and MP4 are containers, not video codecs. An MKV holding H.264 video and AAC audio may be moved into MP4 without re-encoding, while VP9, Opus or unusual streams require conversion. Tubelexity exports the primary video and audio tracks; additional subtitle, attachment and alternate-audio tracks are not silently copied.
How to use MKV to MP4 Converter
- 1Choose a local .mkv file.
- 2Review detected video and audio codecs.
- 3Use fast remux for compatible primary streams or re-encode.
- 4Preview and download the MP4.
Supported inputs and outputs
Inputs
MKV with a primary video stream
Outputs
MP4 video
Practical uses
- Making MKV recordings playable on more devices
- Preparing archived video for web playback
- Creating an MP4 editing copy
Browser and media limitations
- Extra MKV tracks and attachments are not preserved.
- Browser-native MKV preview is limited.
- VP9 or Opus generally requires re-encoding for MP4.
- Large multi-track files require substantial memory.
How local processing works
Processing uses FFmpeg.wasm locally in this browser. The media engine downloads on first use, but Tubelexity does not upload the selected media to a processing server.
Frequently asked questions
Is MKV a codec?
No. MKV is a container that can hold several video, audio and subtitle codecs.
When can MKV be converted without re-encoding?
When its primary streams are compatible with the MP4 container, such as H.264 video and AAC audio.
Are MKV subtitles preserved?
No. This converter exports the primary video and optional primary audio only.
Does the MKV leave my device?
No.