AfterDawn: Glossary

Ogg Media (OGM) is a video, audio and subtitle stream Container format. It was developed by Tobias Waldvogel and has features that common AVI formats cannot do. These features in particular include

• Chapter Support
• Multiple subtitle tracks
• Multiple audio tracks of various formats including MP3, AC3, AAC, Vorbis and LPCM)
• Vorbis audio support as there is no correct way for AVI to support Vorbis

OGM support for Windows comes by way of the creator's own OggDS or Direct Show Filter, Haali Media Splitter, VLC or RadLight's Ogg Media filter. Most of these filters plug-in to Windows Media Player and allow for changing subtitle preferences (possibly between Japanese and American subtitles are one example), changing audio preferences (changing between the native language of an audio stream to an embeded dubbed language) or even simply fast forwarding to a particular part of the video stream much as you would a DVD player. On Unix based machines, OGM support is available through MPlayer, xine and VLC.

Originally, the OGM format was developed as a hack to the Ogg container and some say will only be a temporary solution to replacing Ogg as more mature and feature rich formats are taking preference amongst downloaders. Formats such as Matroska are getting the nod towards wider range of support. The one major drawback of OGM initially was that it was not a free software, even though it was based on the open-source project for Ogg framework. Later, the creator joined the Ogg development team and donated all his code to the Xiph.org people.

Typically and most often, OGM contained files carry video encoded in the MPEG-4 ASP format and audio in Vorbis or AC-3.

How to play OGM files

• An OGM file is an OGG media file. OGM is a container format that can store video streams, audio streams and subtitles. This article shows how to play OGM files and use some of its advantages over the AVI container.... (Read More)