# 1A 45 DF A3 — File format magic numbers

For 1A 45 DF A3, offset is 0; extension is mkv mka mks mk3d webm; format is Matroska media container, verified against its source on 2026-08-03.

- **Hex signature:** 1A 45 DF A3
- **Offset:** 0
- **Extension:** mkv mka mks mk3d webm
- **Format:** Matroska media container

## What the source says

> ki/Free_Lossless_Image_Format> Free Lossless Image Format | 1A 45 DF A3 | ␚Eߣ | 0 | mkv mka mks mk3d webm | <https://en.wikipedia.org/wiki/Matroska> Matroska media container, including <https://en.wikipedia.org/wiki/WebM> WebM | 4D 49 4C 20 | MIL␠ | 0 | stg | "SEAN : Session Analysis" Training file. Also used in compatible software "Rpw : <https://en.wikipe

## Source

- https://en.wikipedia.org/wiki/List_of_file_signatures

Last verified: 2026-08-03. Review by: 2027-08-03.
Part of [File format magic numbers](https://referencesource.org/file-format-signatures/).