OGM Video Format

What is OGM video format? OGM video format (OGG Media) is a container format, like AVI. It has 2 main advantages over AVI: the first is seeking and the second one is the multiplexing overhead. OGM consists of Video and Audio streams. Usually OGM Audio stream is Ogg Vorbis or AC3. Ogg Vorbis is an open source patent free audio codec that can rival the quality of upcoming commercial codecs like AAC, MP3Pro and VQF and which can surpass MP3 and WMA audio. OGM Video stream usually is compressed with XviD or DivX codec.

In 2002 the lack of formal video support in Ogg resulted in the creation of the OGM video format, a hack on Ogg which allowed the embedding of video from the Microsoft DirectShow framework into an Ogg-based wrapper. OGM was initially supported only by closed source Windows-only tools but the code base was subsequently opened. Later, Video (and subtitle) support were formally specified for Ogg but in a manner incompatible with OGM. Independently, the Matroska container format reached maturity and provided another alternative for people interested in combining Vorbis audio and arbitrary video codecs. As a result OGM is no longer supported or developed and is formally discouraged by Xiph.org. Today video in Ogg is found with the .ogv file extension which is formally specified and officially supported.

OGG is another media container format (generally used for audio data) developed by Xiph.Org. Audio stream stored inside OGG container can be compressed using any codec, but OGGs most often carry audio encoded in the OGG Vorbis format. OGG Vorbis is a lossy audio codec. It is popular among open source communities, because Vorbis is completely free, open, and unpatented. OGG Vorbis is used in video games, on many websites. Also, national radio stations such as Radio France, CBC Radio, Virgin Radio provide Vorbis audio streams.

OGM video format is another extention for the OGG container adopted by Windows users to distinguish music (OGG) and video (OGM). Although not an official extention it is used by DivX and Xvid encoders that put video into the Ogg container.

In order to play OGM video file formats with any directshow compatible video player you must install Ogg Vorbis package.
In order to play OGG files with any directshow compatible audio/media player you must install free Ogg Codecs.