best VBR bias & quality prec settings

[jagx]

what is the optimal VBR bias & quality prec settings?
CCE version 2.67

thanks
jagx

[Fr4nz]

Originally posted by jagx
what is the optimal VBR bias & quality prec settings?
CCE version 2.67

thanks
jagx

For quality prec I think a good compromise is 15.

For vbr_bias, it depends how much the film you want to encode lasts.

I think a value between 23-25 is good for films < 2 hours.

If your film lasts more than 2 hours then go from 15 (if it is VERY LONG...for example lord of the rings, which lasts about 3 hours) to 23.

[Mutant_Fruit]

So, if a film is less than 2 hours, i go with 23-25. If the film is really long i go for 23?

[Fr4nz]

I'd suggest 20-23 if > 2h., 15-20 if it lasts ~3h.

[The_Flash]

I think you might be better off basing the bias on the average bitrate for main movie instead of the running time which can be deceiving.

I also have found that a Quantizer value of 16 or less in v2.67 seems to cause too much blocking on flat parts of the image, as well as several other problems mentioned by RB in the helpful thread here: http://forum.doom9.org/showthread.php?s=&threadid=74460

[Fr4nz]

Originally posted by The_Flash
I think you might be better off basing the bias on the average bitrate for main movie instead of the running time which can be deceiving.

I also have found that a Quantizer value of 16 or less in v2.67 seems to cause too much blocking on flat parts of the image, as well as several other problems mentioned by RB in the helpful thread here: http://forum.doom9.org/showthread.php?s=&threadid=74460

Which settings (image quality and vbr_bias) would you suggest for a movie like "The return of the King" which lasts 3 hours and 12 minutes??

[The_Flash]

First of all, I personally wouldn't try to cram that onto one DVDR. Having said that you could probably split it to two discs w/o any compression at all.

Now, assuming you did want to try that. I'd probably start with the bias at 25 and the quantizer at 24. Run a few short sample encodes on selected scenes (high action, low action, dark backgrounds, etc.) and adjust the two settings from there. Since each film is different, what works once unfortunately isn't going to work every time. Especially not in a severe case like this.

[Fr4nz]

Sorry I forgot to say you that I use CCE 2.50, so IIRC it uses different range values for vbr_bias and image quality.

EDIT: I also have to say that the film, removed all the tracks and extras I don't want (so only the film with one audio track), has a bitrate of approx. ~2700kbps.

[The_Flash]

It's tough to say without a little experimentation. And in fact, everyone has their own idea as to what is acceptable. For example you may prefer to sacrifice a little detail for less flat noise while someone else may not.

I actually thought that the VBR Bias value range remained the same between v2.50 and later versions, but I may be wrong. If later versions are on the same scale I think I'd stick with 25, if they are not you can assume trying a value slightly less than that of the default as a starting point.

RB recommends using between 40-50% of the value for the Quantizer or Image Quality Priority. Because your bitrate is so low however I would suggest starting at 20 and adjusting as need be after your sample encodes.

Best of luck, let us know how your project turns out.

[Fr4nz]

Actually I found quite acceptable an image quality of 15 (maybe it could be better with a value between 17 and 20) and a vbr_bias of 20 (maybe I could try values < 20 and see what happens).

[Video Dude]

CCE Basic does not include VBR bias & quality prec settings.

Are these values hard coded into CCE Basic? If so, does anyone know their values?

[EddieTH]

Originally posted by Video Dude
CCE Basic does not include VBR bias & quality prec settings.

Are these values hard coded into CCE Basic? If so, does anyone know their values?
Actually, as of 2.69 Basic does allow you to set the Quantizer Characteristics (quality prec), but DVD-RB only supports it for SP. I don't know what VBR bias it uses though, and I've often wondered.

[Video Dude]

Originally posted by EddieTH
Actually, as of 2.69 Basic does allow you to set the Quantizer Characteristics (quality prec), but DVD-RB only supports it for SP. I don't know what VBR bias it uses though, and I've often wondered.

I was wondering what the default values were for CCE Basic 2.67. Perhaps the default values used in CCE SP for these settings are the ones hardcoded into CCE Basic?