Re: Paramount Makes Official Blu-Ray announcement! Read the press release here.
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Originally Posted by Man-Fai Wong
If a film transfer yields enough noise/grain to push the limits of video compression, then DNR may indeed become necessary, particularly if the format has less headroom to handle it. Whether this has actually been true for any signficant number of cases, I do not know. But there's nothing invalid about what I said unless you can show me that the lower limits of HD-DVD or the use of MPEG2 on Blu-ray would *never* be an issue no matter how noisy and/or grainy a film transfer is -- and I really doubt you can show me that. The fact is the video needs to be heavily compressed to fit w/in the limits afforded by *both* format, but more so for HD-DVD than for Blu-ray. And excess noise/grain can make compression inefficient, which can in turn lead to certain bad effects one way or another. And really, this applies to all sorts of data compression, not just video. Basically, there's no free lunch. Also, what you think is DNR might not be the only kind of DNR going on that might actually be needed. Depending on how one looks at it, stuff like aliasing artifacts can also be considered "noise" that needs filtering afterall. |
This is absolutely correct. DNR, contrary to popular belief, is not always applied strictly for aesthetic reasons IE grain reduction. Sometimes DNR is used because the transfer to a given video format doesn't look look like the original source. Sometimes the transfer will cause exaggerated noise because of the way the film grain interacts with the scan lines of the video format. In these cases and in others the judicial use of DNR can help the video version look more like the original source.
Of course like any useful tool DNR can be abused and a natural looking film can be made to look like plastic, but just because it can be abused doesn't mean its not a useful and sometimes necessary tool. Saying that DNR should never be used is kind of like saying they shouldn't color correct the transfer to make the finished version more like the answer print. I do agree that it should never be obvious that DNR was used.
Doug



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