Why AVC's got 1pass-ABR and XviD hasnt??

[Episodio1]

Why AVC's got 1pass-ABR in its short life time and XviD hasnt in all of these years of development??


Thanks.

[stephanV]

it does...

[Episodio1]

So is it "single pass" and choose the "target bitrate" as "ABR"??

Because when I click on MORE OPTIONS, the window's title is CBR. :(

[Sirber]

VBR is a limited way of ABR IIRC.

With ABR you can do CBR as well as pure VBR.

[Didée]

Why AVC's got 1pass-ABR in its short life time and XviD hasnt in all of these years of development??
Because you did not implement it. We are all waiting for you. :)

[stephanV]

So is it "single pass" and choose the "target bitrate" as "ABR"??

Because when I click on MORE OPTIONS, the window's title is CBR. :(

In video encoding ABR is often referred to as CBR. How "ABR" your encoding is will depend on the settings you use (quant restrictions and such). True CBR (CBR as in PCM) is even almost impossible for compressed video. A 1-pass ABR mechanism will always be very close to CBR anyway if you want it to reach to the target bit rate.

VBR is a limited way of ABR IIRC.
I think you meant to say CBR instead if VBR here...

[Doom9]

Because you did not implement it. We are all waiting for you.good one ;)

[Episodio1]

"Because you did not implement it. We are all waiting for you"

So curiosity doesnt fit in this forum.

Ok, it's good to know.

[chilledoutuk]

it came across as a complaint or a dig at the developers of xvid rather than a question.
Perhaps the developers didnt see any value in developing single pass VBR, I didnt and still dont.

[Teegedeck]

"Because you did not implement it. We are all waiting for you"

So curiosity doesnt fit in this forum.

Ok, it's good to know.
Nah, you can just post any question you can think of, even stupid ones. It's all nice people here. Only asking in a rather complaining tone was not quite the smart thing to do. If you'd put it 'why hasn't XviD got ABR?' you'd have got straight answers but if you sound like complaining about a free software, then you're likely to step on some people's toes and trigger similarly unfeeling reactions. You see, people like Didée, Sirber, StephanV and Doom9 have been spending lots of their spare time to create free tools for the community, so they are sensitive to complaints about free software. If somebody gives you a gift you don't complain that it's not quite the thing you would have bought yourself, you just accept it. See also General conduct - or how to accept a gift properly (http://forum.doom9.org/showthread.php?t=52597).

Edit: BTW, chilledoutuk, single-pass quantizer IS perfect VBR. :p
(Perfect VBR means you have very little control of the bitrate.) The difference between ABR and CBR is just a gradual one; loosen the restrictions on CBR and you get ABR. CBR also isn't ever really constant bitrate. Rather imprecise terms, eh?

[Didée]

Let me add that I would have nothing, absolutely nothing against XviD's 1-pass CBR (ABR) mode allowing a little more VBR :)

It's not like the concepts were not out there - ffdshow's 1-pass mode has been better configurable than XviD's one for a veeery long time, and x264's might be even better (supposely, I never tried it...). It's just that noone seems interested in developing XviD anymore. Have a look at the developer's mailing list (http://list.xvid.org/pipermail/xvid-devel/) - October's archive is about the poorest thing ever seen in there. :( :(

[IvS]

CBR and ABR are inefficient old methods that restrict modern codecs terribly. They restrict what the codec can and should do. The codec wants to do something, "ABR" says "hold on there, you can't do that right now, you're going by my rules, forget all those rules meant to make the format a whole lot more efficient than my lousy oldschool rules". It's the same for video codecs as it is for audio codecs. Vorbis for example does provide an "ABR" method, and mentions that it hurts quality severely because it restricts how the codec *should* work. And there are codecs like XviD for video and Musepack for audio that just don't offer such suboptimal old methods for encoding.

[Kopernikus]

Sometimes it is important to have such constraints. For example if you only have limited bandwidth to transfer a videostream. Then you can't say: "Dear Videocodec. Do what you want."

ABR/VBR/CBR isn't so unnecessary.

[Episodio1]

"In video encoding ABR is often referred to as CBR."

Thanks, stephanv.

I see now, Teegedeck. :)