About OGM and OGG

Is it just the name difference?
I wish it were that simple. The biggest problem is that people are using OGM primarily to encode DVD's with DivX video and Vorbis audio. I fear that people might be using OGM, and convince themselves that they're using completely free software, when they're not. After all, 'Ogg' is from Xiph, and Xiph only produces free stuff. DivX and XviD are MPEG-4 variants, and subject to any holds that the MPEG patents have on those technologies.

Again, nothing wrong with DivX or XviD, they're just not completely open standards. Patents apply. It doesn't mean they're not useful, it just means that you might be getting more than you bargained for on the legal side of things.

More about technical differences between Ogg and OGM (Ogg vs OGM)

Ogg and Ogm file format are the same. The main difference is the first header in each stream. OGM uses several standardised header formats, audio, video and text, in order to make identifying unknown codecs easier in directshow (and subsequently other frameworks). That is with those three headers you can use any audio or video format you choose without have to write custom header parsing routines for each codec in the demuxer.

In other words ogmtools provides the standard du jeur for encapsulating various common-in-avi codecs in an Ogg bitstream, like 'divx', 'mp3' and so on.

There are quick tools to convert OGM to Flash. You may get the best video quality to share online with fast speed.