OGM file format (.ogm)

What is an OGM file?

In short: An OGM file (.ogm) is a video file in the OGM format. OGM was an unofficial attempt to make Ogg carry arbitrary video and multiple subtitle tracks, which the official specification did not support. It can be converted to MP4, MOV or GIF for free in a web browser with iHateFiles, without uploading it.

A community extension of the Ogg container from around 2002, before Matroska took over.

OGM was an unofficial attempt to make Ogg carry arbitrary video and multiple subtitle tracks, which the official specification did not support. It was never standardised, and Matroska did the job properly, so OGM survives only in old collections.

What OGM is good at

• Multiple audio and subtitle tracks, unusual for its time
• Open, in spirit if not in specification
• Still readable by VLC

Where OGM falls short

• Never an official standard
• Abandoned in favour of Matroska
• Support is patchy even among players that read Ogg

When to use OGM

Convert OGM to MKV or MP4.

How to open a OGM file

VLC and a few older players.

The thing that usually goes wrong

Because OGM was never standardised, two files can differ enough that one player reads one and not the other.

Inside a OGM file

OGM was a community effort to make the Ogg container carry video, at a moment when the official Ogg specification had not settled how to do it. Anime fansubbing groups adopted it around 2002 because it could hold multiple subtitle tracks and multiple audio languages in one file, which nothing else convenient could at the time.

It was superseded within a couple of years by Matroska, which did the same job with a properly designed specification behind it. OGM was never standardised and its tooling was abandoned, so what remains is a stratum of early-2000s archives and very little else.