What is OGM?

OGM meaning Ogg Media File, was developed by Tobias Waldvogel. It is a container format (for video, audio and subtitles), which can do a few things the AVI format cannot:* Chapter support* Vorbis audio support (although AVI can support Vorbis audio, it should be considered a hack, and not reliable)Just like AVI, it also supports* multiple subtitle tracks* multiple audio tracks, of various formats (MP3, AC3, Vorbis (not in AVI), WAV)

OGM support for Windows (Including Microsoft's Windows Media Player) is available via Tobias's own OggDS, the less buggy Haali Media Splitter, or RadLight's Ogg Media filters (the latter of which can also decode Theora video, and is available on Unix-based systems with MPlayer). Fundamentally, the format is a hack of the Ogg container format, which has only been designed to support encoders endorsed by Xiph.org (website), the creators of Ogg.

It is most likely going to be viewed as a temporary solution, to be phased out when other media container formats (for example, Matroska) mature and come to support the same services. Originally, a major drawback of OGM was that it was not free software / open source, even though it was based on the open source Ogg framework.

The reason was that Tobias was embarrassed about the quick-dirty-hack quality of his code, wanting to improve it before releasing it to the keen eyes of the Xiph.org people. Tobias has officially joined the Xiph.org team since, and has donated all the code of his DirectShow filters including format manipulation and playback to their BSD-style free software licensed repository. It is available, though without documentation, in the "oggds" module of the repository.