MP4 to MKV Converter

MP4 to MKV Converter | Online Free Tool | Elysia Tools

Tool usage guide

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Category: Media
Input types: file, select, number
Output type: file
Sample coverage: 4
API ready: Yes

Overview

Convert your MP4 and M4V video files into the versatile MKV (Matroska) container format. This tool allows you to repackage your video and audio streams without re-encoding using the copy option, or transcode them using codecs like H.264, H.265, VP9, AAC, and FLAC while adjusting CRF quality.

When to use

When you need to wrap an MP4 video into an MKV container to support advanced features like multiple audio tracks or soft subtitles.
When you want to change the video or audio codec of an MP4 file to open-source formats like VP9, Vorbis, or Opus.
When you need to compress an MP4 video by re-encoding it with H.265/HEVC and adjusting the CRF quality value.

How it works

1Upload your MP4 or M4V video file up to the 100MB limit.
2Choose your preferred video and audio codecs, or select 'Copy' to change the container format without re-encoding.
3Set the CRF quality value between 18 and 28 if you are re-encoding the video.
4Click convert to process the file and download your new MKV video.

Use cases

Remuxing MP4 files to MKV containers without re-encoding to preserve original stream quality.
Transcoding MP4 videos to H.265/HEVC with custom CRF quality settings to reduce file size.
Converting audio tracks within an MP4 file to open-source formats like Opus or Vorbis.

Examples

1. Lossless Container Remuxing

Video Archivist

Background

An archivist has MP4 files that need to be stored in the open-source MKV container format without altering the original video and audio streams.

Problem

Convert the container from MP4 to MKV without losing any quality or wasting time on re-encoding.

How to use

Upload the MP4 file, select 'Copy (No Re-encoding)' for both the Video Codec and Audio Codec options, and run the converter.

Video Codec: copy, Audio Codec: copy

Outcome

The video is instantly remuxed into an MKV file with identical stream quality.

2. High-Efficiency Video Compression

Content Creator

Background

A creator needs to compress a large MP4 video to save storage space while maintaining good visual quality.

Problem

Reduce the file size of an MP4 video by converting it to MKV using H.265 encoding.

How to use

Upload the MP4 file, select 'H.265/HEVC' as the Video Codec, choose 'AAC' for the Audio Codec, set the CRF Quality to 22, and convert.

FAQ

Can I convert MP4 to MKV without losing quality?

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

What is the maximum file size supported?

You can upload and convert MP4 or M4V files up to 100 MB in size.

When should I adjust the CRF quality setting?

The CRF quality setting only applies when you choose to re-encode the video (e.g., using H.264 or H.265), where a lower number yields higher quality.

Does this tool support M4V files?

Yes, the tool accepts both standard MP4 and M4V video formats as inputs.

What audio codecs can I convert to?

You can choose to copy the original audio or convert it to AAC, Vorbis, Opus, MP3, or lossless FLAC.

Video Codec: libx265, Audio Codec: aac, CRF Quality: 22

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Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Lossless Container Remuxing

2. High-Efficiency Video Compression

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