Does converting from WebM to MKV improve video quality?

No, the conversion only changes the container format and preserves the original encoded streams without improving quality.

Can I add multiple subtitles or audio tracks to my MKV file during conversion?

Yes, MKV supports multiple audio and subtitle tracks, and this tool allows muxing those into a single file.

Will my converted MKV play on all devices?

Playback depends on both container and codec support; devices must support the codecs inside the MKV for proper playback.

Convert Your Video from WebM to MKV Format Online

Easily convert video files from the WebM format to MKV using our online converter. Preserve your original streams while gaining flexible container features ideal for archiving and distribution.

Upload Your File | Maximum Size Upto 25MB

Quick Access To 38 WEBM File Conversion Pairs

What Is This Tool?

This online converter allows you to change a WebM video file into an MKV container without re-encoding the original streams. It helps you organize multiple audio tracks, subtitles, and metadata within a flexible, open container format suitable for long-term storage and playback.

How to Use This Tool?

Upload your WebM video file from your device or cloud storage
Select MKV as the desired output format
Optionally add subtitle tracks, chapters, or attachments if supported
Click the convert button to start the process
Download the converted MKV file once ready

Key Features

Converts WebM video files to the MKV container format
Preserves original encoded audio and video streams without re-encoding
Supports adding multiple audio tracks, subtitles, chapters, and attachments
Enables creation of rich metadata for distribution and archiving
Open, royalty-free format compatible with many tools

Examples

Mux a WebM video with VP9 and Opus audio into MKV adding ASS subtitles and font attachments without losing quality
Convert a batch of WebM video captures into MKV files organized with chapters and multiple language audio tracks for archiving
Prepare a review copy by combining WebM files into an MKV container with selectable subtitle formats and alternate audio commentary

Common Use Cases

Archiving web-optimized WebM videos into MKV containers to add metadata and multiple subtitles
Creating screening copies with alternate audio commentary and subtitle tracks in a single MKV file
Converting lightweight web videos to flexible MKV files for offline playback and compatibility with Matroska-based tools

Tips & Best Practices

Ensure your device or player supports the codecs contained in your WebM file for playback after conversion
Use this conversion primarily for muxing rather than re-encoding to preserve quality
Add subtitles and attachments during conversion to enrich your MKV files for distribution or archiving
Test playback compatibility on your target devices since MKV support varies depending on codecs and features used
Avoid using WebM lossy video streams as archival masters; use MKV to organize but rely on original quality

Limitations

Converting containers does not change the underlying video or audio codecs
Playback depends on device support for WebM video codecs like VP9 or AV1 contained within MKV
Older or low-end devices may experience higher CPU usage when playing VP9 or AV1 streams
Advanced MKV features such as attachments or uncommon subtitle formats may not be supported by all players
Some platforms need alternate codecs like H.264 for universal playback, requiring re-encoding rather than container changes

Frequently Asked Questions

Does converting from WebM to MKV improve video quality?: No, the conversion only changes the container format and preserves the original encoded streams without improving quality.
Can I add multiple subtitles or audio tracks to my MKV file during conversion?: Yes, MKV supports multiple audio and subtitle tracks, and this tool allows muxing those into a single file.
Will my converted MKV play on all devices?: Playback depends on both container and codec support; devices must support the codecs inside the MKV for proper playback.

Key Terminology

WebM: An open, royalty-free media container format designed for web video delivery, usually containing VP8/VP9/AV1 video and Vorbis/Opus audio streams.
MKV (Matroska): An open, flexible multimedia container format that can hold multiple audio, video, subtitle tracks, chapters, and metadata in one file.
Muxing: The process of combining multiple streams such as video, audio, and subtitles into a single container file without re-encoding.

Quick Knowledge Check

What is the primary benefit of converting WebM to MKV?

It changes the video codec to H.264

It preserves original streams in a more flexible container

It compresses the video for smaller size

Which of the following is a limitation of this conversion?

It re-encodes the video to improve quality

Some players might not support advanced MKV features

It removes all subtitles from the file

Which codecs commonly found in WebM might have playback issues after conversion?

VP9 and AV1

H.264 and HEVC

MPEG-2 and DivX