How to Convert MP4 to MKV on Windows

What matters

MP4 and MKV are containers, not codecs. The same video stream can often move between them without changing the decoded picture.

If your streams are compatible with MKV, a remux is preferable because it avoids a generation of encoding loss and is much faster.

Step-by-step

1. Step 1If the target requires a different codec, a real transcode is needed and quality/size become setting-dependent.
2. Step 2Check the final file for audio tracks, subtitles and metadata that matter to your workflow.

Keep the workflow local

FastConvert is positioned as a local Windows media converter. The conversion itself is performed through FFmpeg on the machine rather than sending the media to a browser upload service.