Private media conversion
MKV to MP4 Converter
Transcode an MKV's primary video and audio into a broadly compatible H.264 MP4 without uploading it.
The engine downloads once from a CDN. Your media remains on this device.
How to use the mkv to mp4 converter
- STEP 1Choose a MKV file up to 200 MB.
- STEP 2Convert it locally to MP4.
- STEP 3Download the finished MP4 file.
About this tool
MP4 output makes Matroska content easier to use in browsers, phones, messaging apps, presentations, smart televisions, and social platforms.
The first video becomes H.264 CRF 23 and the optional first audio becomes 160 kbps AAC. Fast-start metadata supports progressive web playback.
Processing time depends on duration, source bitrate, output format, and device performance.
Frequently asked questions
Are subtitles and alternate tracks retained?
No. This compatibility converter selects the first video and optional first audio stream. Subtitles, attachments, and additional tracks remain in the source MKV only.
Is my MKV file uploaded?
No. FFmpeg WebAssembly performs the conversion in your browser. The engine downloads from a CDN, but your media stays on your device.
What is the maximum file size?
The browser converter accepts files up to 200 MB. Long files may require substantial device memory.