(I'm stupid, sorry, but:) How to do ModQuant?

[LigH]

Sorry guys, I'm afraid I'm too stupid to find a useful guide how to do an encode with modulated quantizers properly - one reason might be that dialup connections are too expensive for me to search and read for more than half an hour; the other is that Koepi didn't update his "XviD options explained", they are still at the date of March 2002, and there the idea of the modulated quantiser is so vague that I just can't understand what he means.

So I wonder if there is any guide which explains what I shall do when I'd like to use this feature properly. Maybe one of you knows them all very well and can give me a hint. (Or did I point out a possible lack of documentation about this very specific topic?)

[Koepi]

http://forum.doom9.org/showthread.php?s=&threadid=30454

The search function would have brought up that thread very fast :)

[LigH]

Joker... :mad: I know how the search function works -- I just couldn't find the best search pattern: The one I used resulted in a few dozen results, and they were just too many to read them all (you know, online costs); I think the one you listed was not in the results, else I would have found it (just use 'quantizer' instead of 'quantisation', and everything is different).

But anyway - thank you for the link, this helped a lot!

(And still: A fresh XviD help file would be nice, XviD has changed so much since March, just to mention the GUI structure...)

[Gazza]

LigH
As far as I know the latest help (or nearest to it) comes with Koepi's downloads. There are also additional help by hovering the mouse over input boxes. This will provide better information.

Note, these help hints are just that. They can get you going but the best training is to jump in and give it a go.

Wow - I write like Koepi !!! Maybe some of what he has stated over and over again is sinking in..


Gazza

[LigH]

Dear Gazza,

I was indeed talking about that help file which was installed with his codec. For example, after installing XviD-23092002-1.exe, the XviD_Help.chm is of 7th March, 2002 - that's half a year ago.

And the text there is anything but really helpful:

If you choose "Modulated" (only for 2nd pass! If used in first pass it'll result in MPEG quant type!), you have to check which quantizer will get used more often. If the average quantizer in 2nd pass is e.g. 3.7, you should use .h263 quantization type, if 2.5 it's better to use MPEG quant type on first pass.

Let's see what I could understand:

- The first pass shall not be done with "ModQuant".
- I have to check the QF distribution to decide which one (H.263 / MPEG) to use for the first pass...

... but is there a tool which helps me here, or do I need to let DebugView run along and analyse the log at the end? And then I would have to run four passes in the worst case: Two for a temporary file to analyse that for QF distribution, then again two with the correctly chosen first pass QF type if I used the wrong one? Or even better five runs: Each two with either H.263 or MPEG for both passes, analysing both results, and the final second pass with ModQuant?

I just would like to have a small step-by-step guide how ModQuant was intended to be done. Then I will be glad to give you much input about Koepis new HQ ModQuant variant.

And once again, please don't be too mad at me - it is just too expensive to search a long time for hints in so many thousands of topics (even just reading takes its time, not to mention translating and understanding, and finally deciding if the topic I just read was helpful for me). As a jobless computer scientist, I just don't have the money for hours of searching.

[Koepi]

That's the pain with modulated quantizers.
It's still valid as it is describes in the help file.

An educated guess will help you finding the right first pass quant type - in worst case you have to do 3 passes.

Please don't get aggressive when you're lacking the idea of ALPHA testing software - you can't get help on EVERYTHING, you have to understand some concepts yourself.

(Sorry to be rude here, but I dislike that demanding sound of those posts - demand for help that we can't give, you have to check that for yourself to find good guesses, like usual when guessing, experience helps, which we can't simply "beam over").

Regards,
Koepi

[LigH]

Originally posted by Koepi
Please don't get aggressive when you're lacking the idea of ALPHA testing software - you can't get help on EVERYTHING, you have to understand some concepts yourself.

Koepi, I'm sorry if I sounded too raged - it was just hard for me to understand, maybe for one reason that english is not my native language, but maybe for another that I couldn't get to the basics quickly enough.

I really would like to help you, too, because I know that you are one of the most important XviD developers - but as long as I don't understand the basics, I can't send you help for advanced ideas... Well, I hope I'm going to get it - I'll try my best.