[XviD-devel] [TODOLIST ITEM] Bit rate controler module

[Marc FD]

[...]

> i know the API will be harder to code this way, but RC is a crucial part
of
> encoding,
> and there is not only 1pass ABR, 2pass VBR and 1pass const quantizer
modes.
> this way you can implement various RCs, like :
> 1pass hybrid 2pass, 3pass, 1/2pass cluster mode, ect...

>1pass hybrid 2pass ? (explain me what it is)

they idea is to buffer frames and to scan them to know what is coming.
this way, you have consistent information who helps you to makes very
accurate
1pass, that's why it's called "hybrid 2pass". (it's only 1pass, but a smart
one ;-)

>3 pass is no problem.

sorry, i didn't thinked "normal" 3pass (BTW, it's overkill)
2pass is really enough for accuracy.
what's cool is fast 2pass (hybrid 3pass)

it's like hybrid 2pass, but with a little thing more.
it's only interressing when decoding of the source is
very fast. first, you scan the entire file. it's the 1st
pass. it's much faster than encoding. the info you gathered
with this quick 1st pass helps the 2nd pass (a hybrid 2pass-like)
to do RC between a little timescale (scanned & buffered frames)
and a big timescale (entire movie).

of course these RCs are not much better than 2pass nor needed.
it's just cool ^^ (and sometimes fast)

>Look at the code and read the ToDos... i think we have first to sort out
>how we can handle bframes before considering some higher problems... we
>have first make the code consistent for todays use

yes, yes you're right. we should start to get it working well.

>before writing the "universal killer" RC.

it's just that RC is one of the most powerfull
things in video encoding, and is cheap in amost
all codecs. but remember SBC helped to (sometimes) do
magic with a crappy encoder like DivX ;-).
(of course SBC is now crap. it's just an exemple)

XviD's VBR is one of the best. but still far from perfect ^_^

Cheers,
MarcFD