[mat]

It is the second time that I come across this problem:

With automatic 2-pass checked, I've tried to encode my FOTR, special extended edition with 300KBytes/s. The outcome was 417.7KB/s according to DIVA. I havn't calculated myself, but the filesize hints at 417 rather than 300.

Probably it has something to do with DIVA having encoded another movie before (using the wrong log file?). However, I have checked under 3ivx settings that "first pass" showed up.

Any ideas?

[appleguru]

This is a known bug (Actually discovered when encoding a similar movie you yours; LOTR: TTT, EE ;)). It is a bug in 3ivx and is currently being worked on. It only occurs with 2-pass, and with really really long-ass movies ;) This is also an issue in Xvid I think. The video that you got is essentially just QP2; thus the higher than expected bitrate. I bet it looks great though :P

[Stux]

Quote

Probably it has something to do with DIVA having encoded another movie before

No, I think it has to do with the extreme length of the feature...

TTT:EE also causes a dual-pass bug

Until its fixed (which should be in the next update) you will have to encode the movie with another mode, or perhaps chop off the credits or something to make it short (do it in two halves?)

[zav]

Think I ran into the same problem with Nemo.  Single pass at qp2 produced a 2.9 G movie.  Dual pass at best quality produced a blocky 848 Meg movie.

[JWMac3ivx]

I was encoding a 1hr 45min video with 'Dual Pass - Best Quality' and came across the same problem.  I had to use single pass to get the desired filesize.  Nice to know that this is a known problem, I just thought I was crazy and didn't know what I was doing...Well, I guess this is still true.

[V99]

Once again, dual pass is meaningless without specifying a bitrate.  If you don't set one, an arbitrary (to you) default is set.  "Best Quality" means for that specific bitrate, not "Give me the best you've got at any cost".  The latter is single pass constant quality QP2 (or QP1).  2 pass just analyzes the file in the first pass to decide what average quantizer is needed for the 2nd pass to meet the bitrate you asked for.  If you don't have a specific bitrate, 2 pass makes absolutely no sense to use.

(Edited by V99 at 1:50 pm on Dec. 27, 2003)

[Stux]

There may be a second bug of course.

The only dual-pass bug we are aware about occurs on extremely long videos (ie FOTR:EE and TTT:EE) where 2nd pass comes out to the same size as the first pass 7+ Gigs.

[zav]

Sooooo V, one thing I heart about 3ivx is that is appears to give me "best quality while getting the best bitrate it can."  

How do you propose I aim for that?  Can't 3ivx have a mode that does this?  Does it already?

If I don't know the bitrate I want, but the quality I want, because I don't care about a "specific" bitrate, then how can I set that bitrate?  I'd like 3ivx to come up with the bitrate required for the quality I desire on a per frame basis.

[V99]

There are 5 encoder modes.  4 of them are for meeting a bitrate, one of them is not.  If you do not have a specific bitrate, Single Pass CQ is the only encoder mode to use.  If you ignore that and use one of the other 4 without entering a bitrate, the codec assigns an arbitrary (to you) default bitrate which has no bearing on the results you want.

Single Pass - Constant quality (CQ):  "Give me this quality at whatever bitrate it takes"

Single Pass - Average bitrate (ABR): "Try and give me the best quality you can while averaging out to about this bitrate, while guessing about the contents of the file since you don't know what's coming in the future."

Single Pass - Constant bitrate: "Stick tightly to the given bitrate;  Lower quality on complex scenes so that the bitrate stays constant, because I want to stream this file, possibly streaming live.  Guess about the future like in Single pass - ABR"

Dual Pass - Constant bitrate: "Look through the whole file once and decide how to meet the constant bitrate the best way, because I still want to stream this file eventually, but I have some time on my hands."

Dual Pass - Best Quality: "Look through the whole file once and decide exactly what the best average quality you can use that will result in a file that exactly matches the bitrate I asked for and looks better than the single pass ABR because you didn't have to guess."

[zav]

THANK YOU V99!!

I'll try to digest all that and come up with something meaningful.