MKV to MP4 Converter

Convert MKV video files to MP4 format

Related Tags
Files 80 FFmpeg 28 Video 27 Transcode 21 MP4 13

Convert MKV (Matroska) videos to MP4 format. MKV is a flexible container format often used for high-quality video content, while MP4 offers universal compatibility with all devices and platforms.

Click to upload file or drag and drop file here

Maximum file size: 100MB

Only applies when re-encoding. 18-28 is recommended range

Key Facts

Category
Images, Audio & Video
Input Types
file, select, number
Output Type
file
Sample Coverage
4
API Ready
Yes

Overview

Easily convert MKV (Matroska) video files to the universally compatible MP4 format. This tool allows you to transcode your high-quality MKV videos using advanced codecs like H.264, H.265, or MPEG-4, customize audio tracks, manage subtitles, and adjust CRF quality settings to ensure seamless playback on any device.

When to Use

  • •When you have high-quality MKV video files that will not play on your mobile device, smart TV, or web browser.
  • •When you need to transcode video and audio codecs to meet specific platform requirements, such as converting to H.264 and AAC.
  • •When you want to quickly change the container format from MKV to MP4 without re-encoding by copying the original streams.

How It Works

  • •Upload your MKV video file using the file selector.
  • •Choose your preferred video and audio codecs, or select 'Copy' to bypass re-encoding for a faster container swap.
  • •Configure subtitle handling options and set the CRF quality level if you are re-encoding the video.
  • •Click convert to process the file and download your optimized MP4 video.

Use Cases

Preparing high-definition MKV movies for playback on iPads, iPhones, or Android mobile devices.
Transcoding MKV files with H.265 video to H.264 to ensure compatibility with older smart TVs and media players.
Stripping unwanted subtitle tracks and compressing large MKV files using custom CRF quality settings to save storage space.

Examples

1. Fast Container Swap for Mobile Playback

Home Media Enthusiast
Background
A user has a high-quality MKV movie stored on their home server but wants to watch it on an iPad, which does not natively support the MKV container.
Problem
The user wants to change the container to MP4 quickly without wasting time or CPU power on re-encoding the video.
How to Use
Upload the MKV file, set both the Video Codec and Audio Codec options to 'Copy (No Re-encoding)', and set Subtitle Handling to 'Remove Subtitles'.
Example Config
Video Codec: copy, Audio Codec: copy, Subtitle Handling: none
Outcome
An MP4 file is generated in seconds without any quality loss, ready for instant playback on the iPad.

2. Compressing and Transcoding for Web Streaming

Content Creator
Background
A creator has a raw MKV recording from OBS that uses a high bitrate and needs to upload it to a web platform that requires H.264/AAC MP4.
Problem
The original file is too large to upload easily and uses codecs that are not optimized for web streaming.
How to Use
Upload the MKV recording, select 'H.264' for the video codec, 'AAC' for the audio codec, and set the CRF Quality to 22.
Example Config
Video Codec: libx264, Audio Codec: aac, CRF Quality: 22, Subtitle Handling: none
Outcome
A highly compatible, compressed MP4 video file optimized for web streaming with excellent visual quality.

Try with Samples

audio, video, file
Video H.264 Samples
Sample video files encoded in H.264 (AVC) format
matched family video
video
WebRTC Real-Time Communication Samples
Comprehensive WebRTC samples for peer-to-peer audio/video communication, data channels, screen sharing, and signaling server implementation
matched family audio,video
audio, video
Video AV1 Samples
Sample video files encoded in AV1 format
matched family video
video
Video H.265 Samples
Sample video files encoded in H.265 (HEVC) format
matched family video
video

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FAQ

Can I convert MKV to MP4 without losing video quality?

Yes, by setting both the video and audio codecs to 'Copy (No Re-encoding)', the streams are transferred directly into an MP4 container without quality loss.

What is the recommended video codec for maximum compatibility?

H.264 (libx264) combined with AAC audio is highly recommended for universal compatibility across almost all modern devices and web browsers.

How does the CRF quality setting affect my output video?

Constant Rate Factor (CRF) controls the visual quality during re-encoding. Lower values (like 18-22) produce higher quality but larger files, while higher values reduce file size.

Can I keep the subtitles from my original MKV file?

Yes, you can choose to convert subtitles to 'mov_text' or copy them directly, though copying may fail depending on the player's compatibility with MP4 subtitles.

Is there a file size limit for the MKV video upload?

Yes, the maximum supported file size for MKV video uploads is 1 GB (1,073,741,824 bytes).

API Documentation

Request Endpoint

POST /en/api/tools/mkv-to-mp4

Request Parameters

Parameter Name Type Required Description
videoFile file (Upload required) Yes -
videoCodec select No -
audioCodec select No -
subtitleCodec select No -
quality number No Only applies when re-encoding. 18-28 is recommended range

File type parameters need to be uploaded first via POST /upload/mkv-to-mp4 to get filePath, then pass filePath to the corresponding file field.

Response Format

{
  "filePath": "/public/processing/randomid.ext",
  "fileName": "output.ext",
  "contentType": "application/octet-stream",
  "size": 1024,
  "metadata": {
    "key": "value"
  },
  "error": "Error message (optional)",
  "message": "Notification message (optional)"
}
File: File

AI MCP Documentation

Add this tool to your MCP server configuration: 

{
  "mcpServers": {
    "elysiatools-mkv-to-mp4": {
      "name": "mkv-to-mp4",
      "description": "Convert MKV video files to MP4 format",
      "baseUrl": "https://elysiatools.com/mcp/sse?toolId=mkv-to-mp4",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

You can chain multiple tools, e.g.: `https://elysiatools.com/mcp/sse?toolId=png-to-webp,jpg-to-webp,gif-to-webp`, max 20 tools.

Supports URL file links or Base64 encoding for file parameters.

If you encounter any issues, please contact us at [email protected]