VC1 AP: 1 pass vs. 2 pass moderate bit rate: Comaprisions?

[sjchmura]

So .....

For say 720p encodes at 3-4mbit for XBOX360 compatibility etc and size issues.....

Have there been good quality comparisons (using the max quality of VC1 AP) between bitrate limited VBR (necessary for 360 compatibility) and simple CBR? It cuts the encoding time in 1/2.

Also, the impact, at these and higher bitrates of the "quality" slider in the CBR mode. Has this been looked it? Meaning, is 90% really 20% better than 70% or is it again only relevant at very very low bitrates (again, assuming AP, loopback on, look ahead 16 etc).

[zambelli]

For say 720p encodes at 3-4mbit for XBOX360 compatibility etc and size issues.....
Have there been good quality comparisons (using the max quality of VC1 AP) between bitrate limited VBR (necessary for 360 compatibility) and simple CBR? It cuts the encoding time in 1/2.
2-pass VBR will always be better than 1-pass CBR, no doubt about it.

Also, the impact, at these and higher bitrates of the "quality" slider in the CBR mode. Has this been looked it? Meaning, is 90% really 20% better than 70% or is it again only relevant at very very low bitrates (again, assuming AP, loopback on, look ahead 16 etc).
The quality setting in CBR mode controls frame dropping. If set too high, the encoder will drop frames to maintain quality. You don't want that. Leave the quality at default or set it low enough that no frames get dropped.