(http://speeddemosarchive.com/demo.pl?Portal_PC_1427)
You really (really) do not want to use a codec a this step. If you want a clean video, you have to use proper tools for each task.
You can either use startmovie with TGA, which is long but will be the best quality, or consider Fraps, which will be faster, easier, and with the same quality at the end.
Next, append the files with a little editing or something in Vegas for example and render it uncompressed.
Then, when you will have the final video, you could use an encoding tool to make something awesome.
Hmm in fact there is another solution for step one, use HuffYUV (http://www.free-codecs.com/download/HuffYUV.htm) which is a lossless codec. x264 does it too but it’s a bit more complicated.
To add it to your system’s codec list, once you have downloaded the file, right-click on huffyuv.ini, then “install”.
It has a few options but there aren’t that important if I reckon correcly.