About quality settings using avidemux on Linux

[kinematic]

As some of you may have read I've been playing around with XviD encoding and i've gotten some good results and as i'm trying to learn more about it someone suggested to read through the xvid presets thread but this isn't of much help to me because it talks about options to configure the XviD codec wich simply aren't available on Linux.
Another part of the problem is that at the moment i can't really make any sense of it since i'm still a n00b to this whole thing so i've come to ask for some help.

First al all....should I be messing with b-frames and if so when and to what should i change them from the standard of 2 b-frames?

The same thing goes for quantisizer restriction for i,p and b-frames.....is there some sort of rule of thumb on the type of encodings when i should change them?

The last question is about the tuning of the second pass.
I've got several options here:
i-frame boost(%)--a value of 20 will give 20% more bits to every i-frame(currently set to the default of 0).

i-frames closer than...frames...--i-frames appearing in the range below this value wil be treated as consecutive keyframes(also at default 0).

Are reduced by(%)--reduction of bitrate for the first consecutive i-frames,the last i-frame will get treated normally(again at default 0)

Max overflow improvement(%)--how much of the overflow the codec
can eat into during undersized sections(at default of 5)

Max overflow degradation(%)--how much of the overflow the codec can eat into during oversized sections(at default of 5)

there are also some options for curve compression:
High bitrate scenes(%)--the higher this value,the more bits get taken from frames larger than the average size and redistributed to others(at default 0).

Low bitrate scenes(%)--the higher this value,the more bits get assigned to frames below the average frame size(at default 0)

Overflow control strength(%)--0=default from core(let XviD decide),else overflow payback percent per frame(at default of 5).

I know these will probably by n00b questions to you but i don't know what to do with it and we've all got to start somewhere so i'd appreciate some help ;-)

[nm]

As some of you may have read I've been playing around with XviD encoding and i've gotten some good results and as i'm trying to learn more about it someone suggested to read through the xvid presets thread but this isn't of much help to me because it talks about options to configure the XviD codec wich simply aren't available on Linux.
You mean they aren't available in Avidemux? There are other tools that (AFAIK) allow you to set all the options exposed by libxvid. At least MEncoder should allow extensive tweaking of encoder parameters. Note that the options you are looking for may be named differently in these alternative frontends.

The rest of your questions are not Linux- or Avidemux-specific, so I think the XviD forum is a better place to search for answers. Remember to use search first. I'm sure most of those questions have been asked and answered thoroughly before. The b-frames option has been discussed to death.

My personal opinion is that you should leave those options at default values in all cases. You need to know how the codec works with specific sources if you want to change them (and even then it is questionable if anything good comes from the tweaking). Instead of trying to figure out what those parameters do, your time is better spent on optimizing the preprocessing (filtering) applied to the source. You could also learn how to use more advanced tools such as MEncoder or AviSynth (through Wine).

[kinematic]

i actually did do a search with several keywords but couldn't find anything that explains it.
maybe someone can provide some links?

[RyosukeFC]

Check through the old XviD encoding guide that Doom9 did back in the day before x264 and friends came out. It's oriented toward GordianKnot, but the video codec theory discussed applies to all video encoding software (especially as it relates to XviD, which is discussed specifically). If you're talking about Avidemux2, which has been the "current" source tree for some time now, XviD options are almost as thoroughly exposed as they are using the XviD vfw codec under Windows, so you should have no trouble software-wise.

Though in my own tests, I could never get Avidemux (1 or 2), even very recent CVS/SVN snapshots, to sync properly using NTSC source material (either interlaced NTSC or progressive FILM type), as it seems to have some PAL-oriented framerate numbers hard-coded into the program (and even admits as much during the compile if you watch carefully).

So under Linux, mencoder is easily your best bet for video encoding. It's something of a pain to memorize all the command line options, but if you write yourself a simple GUI for it using GLADE or some such with your favorite common options, or even a simple shell script, it gets a whole lot easier...

Hope that helps...