Convert MP4 to MKV

A practical, local workflow for converting MP4 to MKV with optimo.

Last updated: 2026-03-18

To convert MP4 to MKV, run npx optimo video.mp4 --format mkv. MKV can be useful as a flexible container for tooling workflows. Optimo handles format conversion and optimization in a single step.

Command

Convert a file by targeting the output format:

npx optimo video.mp4 --format mkv

Tip: add --dry-run to preview changes.

Why convert?

  • MKV can be useful as a flexible container for tooling workflows.
  • Helpful when you want a container that supports multiple streams.

Format notes

MP4
The most compatible web video container; a safe default for delivery.
Optimize MP4Compress MP4Resize MP4MP4 guide
MKV
Flexible container used in many workflows; commonly remuxed/converted for delivery.
Optimize MKVCompress MKVResize MKVMKV guide

More from MP4

MP4 → WebMMP4 → MOVMP4 → AVIMP4 → OGV

More to MKV

WebM → MKVMOV → MKVAVI → MKV

Frequently asked questions

How do I convert MP4 to MKV?
Run "npx optimo video.mp4 --format mkv" in your terminal. Optimo handles the format conversion and applies optimization in a single step.
Why convert MP4 to MKV?
MKV can be useful as a flexible container for tooling workflows. Helpful when you want a container that supports multiple streams.
Does converting MP4 to MKV lose quality?
Optimo uses sensible defaults that balance file size and quality. For lossless conversion (where possible), omit the --lossy flag. Add --dry-run to preview the result before committing.