2-Pass VBR vs. 3-Pass: Any meaningful quality difference?

[Zoloft]

Is there a meaningful difference in quality between the two? Is it worth the extra time? I've experimented a bit and can't say that I see much difference, except for 3-pass taking considerably longer.

I would be interested in knowing what other people have experienced with this.

[snowmoon]

I used mulit-pass on occasion, but have abandon it completly in favor of single pass encoding. I recommend you look over at www.kvcd.net/forum and research the one pass predicion model for getting the correct size ( within a margin or error ) using one pass encoding.

Saves me tons of time over multi-pass.

[Zoloft]

And the quality is good with single-pass?

[adam]

I personally think that 3 passes vs 2 can make a noticable difference if the source lends itself well to VBR encoding. In other words, if the movie has alot of high movement and alot of low movement scenes than I believe that the bitrate can be further optimized with an additional pass.

1-pass vbr can achieve very good results, arguably as good as 2 or 3 pass vbr, but I'm not convinced it can achieve higher, at least not with a high enough avg bitrate. As far as I'm concerned, 1-pass vbr is good for saving encoding time at the possible expense of some quality and at the expense of some amount of filesize prediction. I choose multipass vbr because encoding time is really of no concern to me. I encode one movie at at time and regardless of my settings its always done by the time I wake up.

[snowmoon]

For SVCD I know from personal experience that one pass beats multi-pass hands down for quality. THe constant quality ability of single pass degrades the whole video gracefully.

[vitualis]

THe constant quality ability of single pass degrades the whole video gracefully.

This may be somewhat subjective, however.

Regards.

[crahak]

There is no clear cut answer for that one. Too many factors to consider. You can do some tests and draw your own results, see if it's worth the extra encoding time (in which situations, sources, etc) I generally encode VBR and it gives me good results.

[Kdiddy]

For SVCD I know from personal experience that one pass beats multi-pass hands down for quality

VERY VERY subjective opinionated statment.

[crahak]

See? People won't agree on it. Too many factors influence (especially the person doing the encoding and watching) Hmmm, kdiddy stop editing your posts :P Makes mine sound weird

[kwag]

http://www.kvcd.net/forum/viewtopic.php?t=1294
http://www.kvcd.net/forum/viewtopic.php?t=1729
http://www.kvcd.net/forum/viewtopic.php?t=1604

In that order please. Maybe after reading, anyone who prefers multipass will have second thoughts

-kwag

[vitualis]

Um... not at all...

There are more reasons to do multipass encoding than filesize prediction.

As for the filter, from what I can tell, that is a technique that can be used for any number of passes and not exclusive to one pass.

Sure, they are methods that can improve single pass encoding (and perhaps to such a degree it isn't worthwhile doing a multipass encoding), but from a purely mathematical standpoint (TMPGEnc excepted since it seems to be optimised for CQ encoding), an additonal pass (all other things being equal) will always look as good or better than not having an additional pass.

Regards.

[bbb]

This thread was hijacked by Kwagologists.

The poster asked for quality differences between 2-pass and 3-pass VBR.

Kwagologist 1: For CQ encoding go to KwagisGod.com.

Kwagologist 1: 1 pass is the best ever!

Grand Kwag: Come to my site by clicking here, here, or here. You are under my spell. Follow me my children and devote your donations to my coffers. Do not think for yourselves. No need to learn standards. Trust in my magical X50000 templates and if that don't work try my X50000+100000KKK template and if that doesn't work change the resolution in half and if that doesn't work try Version 2 template coming soon. It's just that easy!

[vitualis]

I can see a flame war brewing so I'm going to lock this post.

@ Zoloft: Trust your eyes! That's ultimately all that's going to matter if you are making video discs for yourself. If you can't see a big difference between 2-pass and 3-pass in the method you are using (and you think that the video looks okay), then you've answered your own question for yourself.

There are scenarios when you may prefer 3-pass over 2-pass and if you keep on experimenting, you'll get a handle on what YOU prefer to do.

Regards.