A couple newbie questions

[chadsdsmith]

I realize that some of these questions are very subjective, but I have searched these forums and still have a few questions.

1. Does any one have links to any screenshot comparisons of various quality settings vs the original blu ray?

2. Do you guys find that moving from high quality to highest quality makes a difference on a bd25 if a fair amount of re-encoding has to be done? (ie, taking a 30+gb movie down to bd25)

3. Do you find that two pass has a bigger effect on picture quality than the quality setting or no? How much encoding time does two pass add if one pass is taking my computer about 4-6 hours on high quality one pass.(I am more concerned w/ quality, but was just curious)

4. At first I was using the automatic settings, but found that even on discs that had a fair amount of re-encoding to be done, bd rebuilder was choosing good quality, which my mind tells me is not enough (probably placebo effect but whatever). Is this because bd25 really doesn't need a high setting to get nearly identical results? or should I continue to use high settings(and possibly two pass) for any real world difference?

Thanks

[jdobbs]

1. Screenshot comparisons are pretty much useless. It's like trying to judge two raging rivers by looking at a single drop of water from each. When is the last time you watched a movie one frame at a time?

2. Highest quality would make very little (if any) detectable difference on a BD-25 encode. The exception might be if it was an extremely long (in terms of framecount) source.

3. Two pass makes a considerable difference compared to ABR. CRF can do better, but at the expense of size unpredictability. Single pass is faster, but two pass isn't twice as long (the first pass is typically much faster than the second).

4. I'd suggest you leave it set to "Automatic". If BD-RB chooses "Good" -- that's all that is needed based upon the size, target, and complexity. Choosing a higher quality setting will simply take longer without really improving the final product. If you want to be overly careful -- just set AUTO_BIAS=3 (See HIDDENOPTS.TXT).

There might be exceptions to any of these statements -- but the exceptions are rare to the point of being negligible.

[chadsdsmith]

Thanks very much for the response. I agree that screen shot comparisons are pretty useless in real world viewing, but they would give a good indication of the differences (or lack thereof) between the various settings, so I was just curious. I will try two pass on the bigger files.

[jdobbs]

Not really. Lots of things are taken into consideration. Here's an example: Back when CG was new the designers thought that making individual clear images was the best way to improve the overall appearance of a video. Later they found that the human eye "hated" clarity in motion -- so they had to purposely "blur" images in motion in order to make the film look better. If you looked at it frame-by-frame it would actually look much worse, but as a film it was improved. Lots of characteristics of improved encoding use similar concepts -- aimed at the true target (a motion picture) rather than individual frames. In those cases a frame comparison might actually tell you the exact opposite of what you're trying to determine.

[chadsdsmith]

I agree with you that clarity in motion is not always pleasing to the eye. The best example of this would be some of the newer tvs w/ their frame enterpolation technology. The displays make up frames in between actual frames so that they can be refreshed in a way that eliminates the excessive blur often associated with lcds. I can't stand the way it makes movies look like an afternoon soap opera. I will say again, however, that screenshots would be a way of comparing the original source blu ray to the finished product, which will likely exhibit the same kind of motion blur as the original and thus give an idea of what settings work for the individuals preference/ocd reasoning for having settings the way thay are : ).
All of this also depends on the viewing enviroment as well. For example, I have a 55' plasma which I sit about 7ft from. I may notice some degraded quality on a given movie that someone watching a 42' tv from 9' may not. Reallistically, my current setup probably won't show any discernable differences from setting to setting, but I plan to upgrade soon to ether a larger flat panel or possibly a projector setup. In that case, I would prefer to have the best backups I can so I can keep my originals locked up and out of the way of my 2 yr old lol. With all of this said, i can tell you that your software is amazing and has surpassed all expectations. I was always used to dvd compression and could always notice the difference between original and backup if anythng over 10% compression or so was being used. On blu ray, the level of quality is very impressive at even 20-30% compression. Thanks again for the response.