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How many passes?

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(Disussion continues from the review thread)
Originally posted by: bongloads
...the official Cinema Craft Encoder Manual DOES NOT SAY "image quality slightly improves each time encoding is repeated, but quality improvement reaches its limit at 3 ~ 4 times of encoding" (you probably pulled that from someone's extremely uninformed guide). Yes it does, in the manual for CCE-SP 2.50. And in Doom9's (extremely uninformed ) CCE FAQ it is stated that this also holds true for later versions. Of course it does.
Originally posted by: bongloads
But it DOES state that "image quality improves with each additional pass". Albeit a small increase in overall bitrate, it IS an increase.
Huh? Since when did an additional encoding pass increase the overall bitrate? The whole idea of carrying out multiple passes is to optimize the allocation of the available bits to where they are needed the most, at the expense of less complex parts of the video. The overall average bitrate remains the same. (Why I have to explain this to someone who claims to have extensive knowledge of encoding is beyond me.)

My laserdisc rips were encoded with 3 passes. I couldn't tell any difference between pass 2 and pass 3, but I did use a relatively high bitrate. (Also bear in mind that encoding video originally from a laserdisc source is less demanding than the sharper, more detailed image from a digital source).

In the opinion of the Doom9 FAQ author, anything more than 3 passes is just a waste of time. The DVDR Releasing Standards state that if the final average bitrate is over 4000kbps then 5 passes are required.

It would seem that a 9-pass encode is an excessive waste of PC resources for no additional advantage. In my opinion, the average bitrate is 10 times more important than the number of passes you use - which is why my DVDs have 192kbps AC3 audio (which incidently is the bitrate recommended by Dolby labs for 2 channel audio) to make more room available for the video.

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thanks Moth3r for the info,i know it was directed to someone else, but i still found it very informative.
DJ
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Moth3r,
Ok, first, way to rip me apart for the term "overall bitrate" - I mean, of course, overall image quality. Which I will tell you again and again that the more passes you do, the better your DVD image will look. It might "seem" to you to be an excessive waste of PC resources for no additional advantage, but have you actually put that theory to test? Well I have, and I have the discs to prove it. Check out my post to a.b.starwars - I presume you own the original - and tell me that a 9 Pass isn't silky smooth. Note the aliasing of text in the reduced quality menus and the relative lack thereof in the introductory scroll and end credits (which is absolute HELL on an encoder). And I did a 2 Pass on the extras disc, and it looks like shit in comparison - with a much lower starting overall bitrate, I might add. Clearly not a waste of "PC resource". In fact, how long does a 3 Pass take really? Maybe 3 hours, sometimes 2. My 9 Pass discs usually take from 8 to 10 hours. Set it up while you sleep, let it run all night, get up in the morning to a beautiful encode. Really, what is your computer doing at night anyways? Take a look around the scene and notice that all the DVD release groups use 6-9 passes, why do you think that is? You think Cinema Craft Encoder does all those extra passes for fun? No. It's an option for a reason, most people are just to lazy to do some tests and find out. Now granted, laserdisc copies of Star Wars maybe don't have the highest bitrate to begin with, but when does it really count - STAR WARS, that's when. If I spent endless hours perfecting a laserdisc rip, you can bet I wouldn't cheap out on the encoding. What if, just what if, you would have "wasted" a few more hours of your pc's precious idle time and gone all out on the encoding? It would have looked even better, I guarantee you. Iron F'n Clad.



-Bongloads.


"Knowledge is power, hide it well."

sigs are for teh gheys
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Not that I am an expert or anything but, I know that all the release groups of dvds do at least 6, I believe there is even a push to do at least 9. But Like I said I am no expert, far from, I dont know how the 3 pass would compare to the 9 pass.

Wish I was home to check out bongloads post a.b.starwars.
Set it up while you sleep, let it run all night, get up in the morning to a beautiful encode. Really, what is your computer doing at night anyways?

Posting to a.b.starwars