What kinds of attachments can an MKV hold?

Anything. MKV attachments commonly include subtitle fonts, cover art, chapter/cue XML data, and other files the publisher bundled with the video. The extraction preserves the original bytes of each attached file.

Does this re-encode my video?

No. Only the attached files are copied out; the video and audio tracks are not re-encoded or downloaded.

Extract attachments from an MKV file online

Q: How are the extracted files named?

Extracted files are named by their position in the container (attachment-0, attachment-1, …) so they stay unique and predictable.

Some MKV videos carry more than video and audio. This page extracts attachments from a .mkv file — fonts, images, subtitle data, or any other file that was embedded in the container.

How to extract MKV attachments

Upload a Matroska (.mkv) file up to 80 MB.
Press Convert file.
Download each attached file from the result page.

What you get

Every attachment stream the MKV declares, available as a separate download up to 32 files. Files are copied byte-for-byte and named by their position in the container (attachment-0, attachment-1, …).

When this helps

Subtitles reference a font that you need in the same folder
You want to inspect the cover art or thumbnail stored inside the video
An MKV bundles extra data (cue sheets, XML, images) you need as files

This extracts attachment streams only. Video, audio, and subtitle tracks are ignored, and no re-encoding happens.