Naiara

From MKV
to MP4.
Done.

Keeps the moving picture and the sound, if the original has it.

Convert my file

We don't keep your files after converting them.

Got several? Open your workspace

What do you want to convert?

Or drag it here · Up to 50 MB

Video

Keeps the moving picture and the sound, if the original has it.

The first video track and the first audio track are converted. Extra tracks and subtitles are left out.

Videos up to 10 minutes and 4K. The first video track and the first audio track are kept; subtitles and extra tracks are dropped.

Processed only for this conversion. The original and the result are deleted from the server when it's done.

Start with what you want to do.

Pick the result. We'll set up the conversion.

Browse all formats

What file do you have?

Pick its category and we'll show you what you can do with it.

My file is PDF. I need it as…

TXTText onlyJPGOne image per pagePNGOne image per pageWEBPOne image per pageDOCXEditable contentPPTXEditable contentXLSXDetectable tablesMDEditable content

One, ten,
or all at once.

Mix formats in the same queue, check the preview and download everything in a ZIP. Unlimited files per batch, free.

Open my workspace
Memories.jpgPDF
Presentation.docxPDF
Interview.mp4MP3

Example layout · your files are only processed when you press Convert.

All your tools.
Your way.

Every tool is free. Choose Plus to use AI, work without ads and restore your photos every month.

Naiara Free

€0

Free, with ads.

  • Every format and tool
  • Unlimited files per batch and ZIP download
  • Previews and private files
Start for free
Naiara PlusNo ads

€9.90 / month

One subscription for AI and your restorations.

  • AI features: summarise, translate and rewrite
  • No ads in any tool
  • 10 standard restorations every month
  • Everything in Free included

Renews automatically every month. Cancel from your account. Restoring and colorizing uses 2 credits. Monthly restorations don't roll over; credits bought in packs are kept. Technical limits per file still apply: 50 MB and up to 10 minutes of audio or video.

Changing formats should be this easy.

Your files are never published and don't appear in your restoration history.

  1. 1

    Choose your file

    Select one of the 54 supported formats, up to 50 MB.

  2. 2

    Tell us the format you need

    You'll only see options that work with your file. The conditions of each conversion appear before you start.

  3. 3

    Download and get on with your day

    Save the result from this tab. If you convert a multi-page PDF to images, you'll get them together in a ZIP.

How to convert MKV to MP4

MKV (Matroska) is a very flexible container: it can hold several audio tracks, subtitles in multiple languages and almost any codec. That flexibility has a cost: many phones, TVs, video editors and browsers will not play it.

This converter turns your MKV into an MP4 with H.264 video and AAC audio that works on virtually any device.

Step by step

  1. Click Select file and choose the .mkv video (up to 50 MB and 10 minutes).
  2. Check that Convert to shows MP4.
  3. Click Convert video to MP4 and wait; it can take up to two minutes.
  4. Download the MP4 and check the audio language.

Audio tracks and subtitles

This is the most important thing to know about this conversion: only the first video track and the first audio track of the MKV are kept. If the file has several languages, the MP4 will contain only the one listed first.

Subtitles, whether text or image-based, are not included in the MP4, and neither are chapters or the attachments an MKV sometimes carries.

Re-encoding and limits

The video is always re-encoded to H.264 and the audio to 160 kbps AAC, even if the MKV already used compatible codecs. That makes the result predictable in any player, at the cost of a small quality loss and a conversion that takes longer than a simple container swap.

Videos up to 10 minutes, 4K resolution and 50 MB are accepted, so full episodes and films will not fit. The MP4 is ready to start playing while it downloads if you put it on a website.

Frequently asked questions

Are the MKV's subtitles kept?
No. The MP4 contains only the first video track and the first audio track.
Can I pick the audio language?
No, the file's first audio track is used. Reorder the tracks in the MKV beforehand if you need another one.
Does the video lose quality?
It is re-encoded to H.264, with a small loss that usually is not noticeable.
Why can't I convert a whole film?
The limit is 10 minutes and 50 MB per file.