My footage is from a Cananon Vixia HF S10
It is AVCHD full hd that records in .mts The clips are 1920 by 1080, most likely progressive instead of interlaced, although I'm not sure how to find out.

So far, I've been converting them with WinFF (Im running Ubuntu Lucid Lynx) to NTSC DVD Fullscreen (although my monitor is widescreen). It works fine for editing, but I cannot render files that use certain video effects (like Speed, set to 1000%). Im not even sure which profile i should be rendering in, but since Im producing mpeg clips, I figured that rendering to Mpeg2 2pass would work best.

Ok, so a few questions, using the clips ive exported already, which profile should i be using for rendering.

and am I converting my camaras files in the best way, what is the best way, should i use something other than winff, or should i use a different profile within winff, and then which profile should i render with after that.

Basically, what is the best combination for exporting and rendering for ubuntu's lucid lynx with a newer typical full avchd camcorder?

any help with this would be appreciated, i don't understand the differences between any of these file formats.

Also, considering that rendering often crashes for me, at about 14% into a file, is it because i need a repository to update kdenlive? Is there a repository for support, if so what is it?

Thanks

By converting to NTSC DVD you loose your HD quality.
You can use Kdenlive's transcode feature to convert to DNxHD, which should be fine for editing.
Regarding the crashes: What version of Kdenlive (and of MLT) do you use? Which distro?