I'm not 100% sure what that format is DORIFTO_N()B, but I'm guessing some low bitrate wmv. I wouldn't bother converting a lossy render to another lossy compression.
Get yourself
VirtualDub, and re-capture your run in a lossless format.
Lossless codecs I've played with:
- HuffYUV: is a very fast, lossless Win32 video codec.
- Arithyuv: is a lossless video codec designed for video capturing.
- Helix YUV Codecs: are two almost identical Video for Windows compatible codecs for decompressing/viewing I420 and YV12 AVI files or the output of AviSynth scripts...
- TechSmith Screen Capture Codec: is a lossless video codec optimized for screen recording.
- Lagarith Lossless Video Codec: offers excellent compression, the MSU Lossless Codec and FFV1 are the only codecs that outperform Lagarith in terms of compression.
- MSU Lossless Video Codec: easy-to-use and understand interface.
- YV12 QuickTime Codec: consists of an image decompressor component, an image compressor component, a movie importer component, and a movie exporter component.
I still prefer to capture with huffyuv in VirtualDub. Be warned though, files can become quite large (it is lossless afterall). Lagarith is pretty good too - slightly more compression than huffyuv for smaller files but a greater chance of dropping frames on a slower computer as a result.
Then take your lossless avi's and edit in your fav video editor. For best video quality, do not use any lossy codecs until your final render.
Since youtube converts yor video to flv anyways after it's uploaded the only benefit you get from heavily compressing your final render is a shorter upload time. Like the rest of the guys who commented, my files were usually 40-50mb's and encoded with xvid because it is YouTube's preferred upload format.
(I suppose the other train of thought is that Youtube is gonna kill image quality anyways, so theres no point in trying to keep it. But that's not my way of thinking )