Once upon a time downloading video with a BitTorrent client meant you needed DivX, XviD or one of the other AVI wrapper codec combinations installed on your system for video playback to function properly. While DivX is still wildly popular for HD file sharing, particularly in the television show swapping space, a couple of unlikely formats are making headway in the lower bitrate space.

OGM has been around for awhile, but it’s only recently started gaining traction in the file swapping space as a viable alternative to AVI wrapper formats. Depending on who you ask, OGM supposedly maintains audio and video sync better than AVI wrapper format DivX, although I haven’t found any science to back that story up. OGM vaguely translates to Ogg Vorbis Media. The wrapper uses OGG audio combined with Theora (and occasionally DivX) video for playback. Theora is billed as an open alternative to MPEG-4, based on On2’s VP3 codec, which is a complicated way of saying Theora is an open solution for playing back video, unencumbered by the licensing complexities of MPEG-4.

VLC Media Player is currently the only media player with native support for OGM, but thanks to efforts of the RadLight team, there’s a Ogg Media filter that makes it possible to configure Windows Media Player to play OGM through a slightly convoluted series of steps.

I previously mentioned the rising popularity of RMVB, which is also making inroads on the space previously owned by DivX. RealMedia Variable Bitrate is gaining traction in large part due to the Helix Community nurtured by Real. While those of us who followed Real’s history maintain a certain level of prejudice about anything attached to the company’s name, they deserve credit for creating a great codec in their more recently releases. The tool sets available for personal use are still less than perfect. Combining RMVB video segments requires tracking down the right tools and dealing with the quirks of apps like Easy RealMedia Tools (which works great but doesn’t include English instructions), until someone in the community further simplifies the RMVB manipulation process.