Blood Diamond Redux
Specifically, Kevin informed me over email that using tools at his disposal he was able to determine that the VC-1 video encode for Blood Diamond, which is identical that on the Blu-ray Disc, is at an Average Bit Rate (ABR) of around 13Mbps over the entire program. According to Kevin, this is approximately the same ABR he found for the VC-1 encode of The Matrix on HD DVD, which is stunning in its image quality, and further that the total amount of disc space used for the entire spate of program material on the Blood Diamond Blu-ray Disc is 22GB (what makes that last even more bizarre is that Blood Diamond apparently is replicated on a 50GB, dual-layer BD, but using less than half that capacity?).
His point is two-fold. One, comparing the bitrates for two different titles isn't an inidicator of image quality as the source material for any two different programs can vary in quality, and also have dramatically different data requirements as far as how much data is required to produce a good image. Two, the bit budget issue is simply false because the 22GB total of the entire program for Blood Diamond on BD wasn't even close to maxing out a 30GB HD DVD disc.
Let me say first that I don't have a problem admitting being off-base on this, or to put it bluntly, being wrong. I posed my original Blog on this in the form of a question and made clear that speculation was involved. But being stubborn there are a couple of additional things I think are worth saying here.
As a metric, ABR over an entire program has the potential pitfall of not necessarily indicating whether the bitrate in many individual scenes dips low enough to denigrate image quality in those particular scenes. And while The Matrix may have encoded spectacularly well at around 13Mbps, the opposite has also been true. Other movies have required much higher data rates to achieve spectacular results with VC-1, according to Kevin Collins' own data. Aside from the obvious stuff like blocking artifacts and excessive noise, would Blood Diamond have at least looked sharper overall with a higher bitrate?
So, to me some question still remains as to whether BD's needs in this regard were properly met, regardless of reason. Noting that Blood Diamond has a lower ABR that's similar to titles that do look spectacular doesn't really answer the question of why BD looks so soft overall in HD. Is the source material of this recent movie that flawed? When the transfer was made did the people involved at any point get concerned with what they were seeing and compare the results they were getting to the same scenes running at the higher data rates that have been required for some titles? Don't know. All I do know is that like a lot of reviewers I was expecting more from an HD transfer of such a recent film.