Complete open format to export

I want to use a customized format to export timeline labelled "Free DVD 6mbps" specifying "mkv" extension and this line/parameters:
vcodec=theora acodec=vorbis video_rc_min_rate=0 video_bit_rate=5744000 audio_bit_rate=256000 frequency=44100 size=720x576 progressive=1

But when I export a video with this, the result is not playable with VLC/MPlayer/gxine/totem and not valid as a clip for Kdenlive project.
Which is the best solution to generate the most compatible and open video file format?

Forums:

I'm not using theodora yet. for genral usability, mpeg, it's the most widly used. though quality and compression suck on it. divx is always a good genral

Ok, but I'm asking for open formats, and compatibility/usability only if it's possible.

The last versions of ffmpeg seem to support Matroska formats.