OPV Encodes on Big TVs

[halpern]

Has anyone tested OPV encodes on large TVs, like 45in+? I am asking because the encodes look great on my computer as well as my tv but I do not have a large one. I'm thinking that they look fine on smaller TVs but as the TVs get larger, VBR (multipass encodes 6 passes for example) would be more suited for such tvs. Does anyone have a large tv and could give me their opinion on the quality of OPV encodes on those TVs? i.e. blocky, pixelated etc.

[pg55555]

Please do a search before posting.

In this same page of the forum you can find the threadhttp://forum.doom9.org/showthread.php?s=&postid=601544#post601544
whose title is OPV vs 6 Pass VBR

Regarding your 45 inches TV, the quality is subjetive, so just try it yourselve

[halpern]

Sorry I should have searched..My mess up :). Thanks buddy.

[halpern]

I was lookin more for someone who actually has a larger TV and has seen the differences. I can't seem to find any post stating differences being viewed on large sets. I don't have access to one or I would test it. I tend to in the near future that is why I'm asking. If you're viewing OPV rips on your computer thats one thing but once you start to increase the TV size I'm assuming it could greatly affect the image quality of OPV rip.s

[Fishman0919]

I have a 64' Pioneer Elite and both OPV and 2 pass CCE look outstanding. I have sat in front of my TV looking at 10-15 sec clip from some of the hardest scenes I could find with CCE 2.50, 2.66, 2.67, 2.70 with OPV up to 10 passes till I couldn't see any more. I came to the conclusion (for me) that anything more then 2 passes even on the hardest stuff is a waste of time. I removed all ver of CCE from my machine but CCE Basic so I can't do more then 2 passes and waste time.


Sorry for the babbling, to anwser your question... yes OPV looks great on a big TV's.

[Sir Didymus]

Originally posted by Fishman0919
I have a 64' Pioneer Elite and both OPV and 2 pass CCE look outstanding. I have sat in front of my TV looking at 10-15 sec clip from some of the hardest scenes I could find with CCE 2.50, 2.66, 2.67, 2.70 with OPV up to 10 passes till I couldn't see any more. I came to the conclusion (for me) that anything more then 2 passes even on the hardest stuff is a waste of time. I removed all ver of CCE from my machine but CCE Basic so I can't do more then 2 passes and waste time.


Sorry for the babbling, to anwser your question... yes OPV looks great on a big TV's.

Hi Fishman0919. :)
Just want to quote. I dont'have a huge TV like you, but did some testing. These tests and my personal experience lead EXACTELY to the same conclusion you stated.

Cheers,
SD

[halpern]

Awesome. Thanks alot man. I have been getting made fun of by some friends thats OPV sucks and that it will be horrible on big tvs. Of coarse I don't really care but it is good to know you don't see much of a difference. Thanks for the input. Much appreciated.

[jdobbs]

The quality you will get from OPV is fixed based upon the Q value. It will be very close to what you'd get through multiple passes that would result in the same output size. My tests have shown that multipass usually does better when compared by the "numbers" -- but the difference is seldom at a level that you could visually detect. On occasion I've even seen OPV do better.

The disadvantage of OPV is not directly the quality -- but the size prediction. While a multipass encode can be pretty much coaxed to go all the way to the edge of the DVD, OPV may not have the granularity to do that. For example, you may choose a Q that leaves 400MB unused, and then decrement the Q by 1 only to find out it has become 400MB too large.

[halpern]

Ok thanks Jdobbs. It has cut my time down to 1 hour for a full movie doing OPV which is a very big decrease in time. The comparisons of OPV to Retail look so simliar that I really can't tell the difference. I just figured blowing it up to a huge size on a big TV would definately make the image more pixelated and have more artifacts. Thanks again everyone!

[archaeo]

jdobbs wrote:
The quality you will get from OPV is fixed based upon the Q value.

At what Q value do you usually think about a multi pass? Is it based primarily upon how close you get to full disk? I had read some of Ddogg's earlier posts regarding OPV and he mentions something about a 'sweet spot' for OPV's being around 18-32.

[halpern]

For OPV I have a Q value of 16 which is default I believe for .70 of dvd-rb. For multipass what I would normally do is set it for says 6 or 8 passes and just let it run. So I'm assuming its using the default values. I never really analyzed the .vaf file. I did for my first few dvd rips because thats what the guides had stated. Eventually I just set it for the # of passes and let it run. Q value of 16 for OPV seems to produce great results so far.

[archaeo]

For OPV I have a Q value of 16 which is default

I believe you're talking about 'Quality Precision', which is different from the Q-value obtained from OPV.

[halpern]

That I didn't know. How do you set the Q Value when doing OPV?

[archaeo]

You don't.
Check out this post: http://forum.doom9.org/showthread.php?s=&threadid=87851

I went through the same learning curve regarding OPV :)

[halpern]

Thanks for being understanding. I'm just so used to the old Roba method. I'm still trying to realize that this OPV might be just as good as 8 passes hehe.

[jdobbs]

Originally posted by halpern
Ok thanks Jdobbs. It has cut my time down to 1 hour for a full movie doing OPV which is a very big decrease in time. The comparisons of OPV to Retail look so simliar that I really can't tell the difference. I just figured blowing it up to a huge size on a big TV would definately make the image more pixelated and have more artifacts. Thanks again everyone! I'd like to clarify that the OPV method to which I'm referring is relates to CCE. I do not recommend one pass encoding using QuEnc except when you are in a terrible hurry, as the quality definitely suffers. QuEnc's one pass encoder is not Q based.

[jdobbs]

Originally posted by halpern
Thanks for being understanding. I'm just so used to the old Roba method. I'm still trying to realize that this OPV might be just as good as 8 passes hehe. That's a common mistake people often also confuse Q with quantization (to which it is related, but not not exclusively).

There is no literal "Q" value fed to multipass -- but you can be assured that the resulting "Q" is the highest it can be for a given target size.

The other big down side, of course, to OPV is that you have to own a copy of CCE SP -- which isn't cheap. There just happens to be a lot of video professionals who visit DOOM9 -- so the likelihood of someone owning it is higher than the world at large.

[halpern]

Exactly ;)