This clip from Fallout 3 is more interesting because of the complexity of the scenery then the actual content. For the most part, when I convert raw FRAPS footage from 1600x900 down to 720p x264 w/ AC3 128Kbps audio at CRF 21, I get a video in the 2000-4500 Kbps range. This particular clip instead weighs in at 18200 Kbps (and one 20 second segment hit 21000 Kbps).

So it will be interesting to see whether YouTube can encode this at anything approaching a decent quality. The really dense and difficult to encode spot starts around 00:20 and lasts till around 00:50 as we move through the tall clumps of grass. On the x264 version, you can see the individual blades in the texture quite clearly.



Now, still images aren't the best way to see video encoding issues, but in this case, the still frames should make it clear in comparison.





The upper frame in each pair is from YouTube 720p, the lower is the x264 720p video (CRF 21). Look closely at the crispness of the road texture, the individual stalks of grass, or the trees on the horizon.





Another good example. On the x264 version (again, CRF 21) you can see that the object on the left horizon is a billboard because you can see the boards that hold it up. On the YT version, it's much more of a grey muddle and harder to determine what it is.

(Yes there are small differences in which frame I managed to screen cap... I tried really hard to get within a frame or three though.)

All that being said, this particular clip is extremely taxing on any codec. The main reason that the x264 holds up so well is that the upper limit on my encoding for the bitrate is 40000Kbps (--vbv-maxrate / Max local bitrate (kbit/s) / default of [0]). Which is compatible with BluRay.