question about Bframes quant

[gatekeeper_007]

I wanted to ask about this for some time now.

-when I use, quantization for Bframes :3 and /Bvops:1/1.50/1.00 or quant 4/, Bvops 1/1.50/1.00 or quant 4, /Bvops:1/1.25/1.00

it seems I always get the same result, something like this...

6202

now, if I use a quant 2, /Bvops:1/1.50/1.00 or quant 3, /Bvops: 1/1.25/1.00 or quant 4, /Bvops: 1/1.00/1.00

I get ... all the B frames at a quant 4 quality none at quant 5 and the P frames of quant 2 are droppin' some %.

#My question is >>> Look at the pic. above...> how can I swap the B frames of quant 5 with those from quant 4.
I meen : let's say with the first example settings I'm getting a B frame average quant 4.75 and with the second a quant 4.00, how can I get a 4.25.

I hope it's clear what I'm asking for.
pc. pls don't tell me that: Bvop quant=((........
I've tried so many different combinations and it always will be the 1st way or the other when I want something in the middle.

Thx.

[gatekeeper_007]

something I forgot to say...
when I go for 2pass encode everything works fine.
The problem is when I need to compress something on the fly 'single pass'


I'm sure... that I'm doing something wrong
I'm just tryin' to find out what...

[Brother Darrell]

Don't know if this answers your question, but something that more is in line w/keeping b frames hugging the p frames, is setting your bquant ratio to 162 and offset to 000(or 1.62 & 0.00 if you are using VFW) You can also set max brames to a higher number and sensitivity to 30. I sometimes use the Nx/30 settings for encoding at 1024x.
( But then...I always do a 2pass encoding. ) Hope that helps in some way.

[DarkZell666]

You don't sound very clear about what you're asking.
Ah yeah, you'll need to put some coma's in there 'coz I'm having trouble reading your post ... lol.

Maybe once the attachment will be approved we'll have a better idea of what's going on :)

[foxyshadis]

The bframe formula is very simple, with CQ: (Quant * Ratio) + Offset, rounded down. A quick algebraic rearrangement should tell you how to get them to have the quants you want.

[gatekeeper_007]

1st I want to thank you all.

@Brother Darrell
If I recall... I allready tried something like that _didn't help either.

@foxyshadis
what makes me post is that when I do a 2pass enc. I get what I want
but when I do a 1pass enc. let's say I want 4.25 or 4.50 ok? well... I get 4.00 or 4.75 but no 4.50 or 4.25 (whatever settings...) which is totaly stange.
plus...the difference I get is not caused by the pframes

pc. I've start thinkin' about unistall everything which have to do with the encodes and reinstall them back.
I haven't done this for a very long time and I've got tones of programs installed for that matter, maybe something gets the codec 'confused'
I know it's a full's thought but I can't think of anything better...

[foxyshadis]

You don't have to do anything so drastic as a reinstall to fix xvid. Just get the latest version, and hit "load defaults" to wipe all settings out.

The average B quant depends on the average P quant; if you're encoding to q2 and want all q4 Bs, just set b-off to 2 and b-ratio to 1. B frames won't necessarily average out to exactly what the formula gives, unless it's an integer value, though it will come close.

btw, if the screenshot is important you might want to upload it to an image hosting service.

[henryho_hk]

gatekeeper, if you want average non-integer quantizers in constant quantizer mode, I can only think of using "zones" (different quantizers in different _pre-defined_ ranges of your movie). On the other hand, if you know your materials well, you can try the constant bitrate mode, which also gives you non-integer quantizers in average.

~~~ Don't hit me ~~~ :P

[gatekeeper_007]

@henryho_hk
I don't use constant quantizers because I like to control the final size,(exept for the credits).

@foxyshadis
I've tried it_but nothing//I even moved to an older version to see what happens_again nothing...

so I did what I had to do for sometime now, unistalled everything (plus manualy deleted what couldn't be unistalled)
and reinstalled only what I need the most, each with a reboot.

... problem solved!

I'm not that smart when it comes to computers, so I can't really say what was the cause of it, and the truth is that I don't care anymore :)
even though it still remain's strange that it would affect only the single pass.

thx for the replys

pc. I'm really sorry about postin' this, but the truth is that at first I thought that was just a settings false of mine, afterwards I begane to realize that it had nothing to do with it...