HOWTO: CompCheck with XviD dev4api / 1.0beta in GKnot 0.28.x

[LigH]

Because several users in the german doom9/Gleitz forum asked if it is possible at all, I'd like to tell you which settings worked for me:

After pressing "Save & Encode" in the preview window and setting up the AviSynth filters, activate CompCheck, and set up the XviD codec as follows:
Choose "Twopass, 1st pass" in the encoding mode combobox
Disable "Discard first pass" in the "1st pass" tab in the dialog which appears when you click the "..." button to the right of this combobox
Because GordianKnot 0.28.x reads the frame sizes from the finished AVI file into a file called VDENC.LOG, the AVI file containing the CompCheck result must be written with full frames, not with drop-frames as usual for a 1st pass - else the VDENC.LOG file would contain "0 bytes size" statistics for each frame, which is not useful.

Please don't blame me if this was already documented somewhere; at the moment we have many complaints about the lack of guides covering version 0.28.x of GordianKnot, especially in german language (the guides about versions up to version 0.27 are outdated at this point) - so I hope this hint is more helpful to many users than annoying because of repeating probably already known facts...

[Doom9]

at the moment we have many complaints about the lack of guides covering version 0.28.x of GordianKnot, I was under the impression I had updated the guide only a short while ago. Did I miss something? Obviously XviD 1.0 is not included because it was neither available at that time, nor is it officially supported in GKnot right now.

[LigH]

As far as I know, the guide was not yet translated into german - at least I didn't find it by looking quickly over the current german guides, the DivX 5 guide still contains a link to 0.27, and the XviD guide still recommends processing the video in VirtualDub after preparing an AVS.

-

And you know: There are users who don't even know Forum Rule #1... :rolleyes:

[len0x]

I don't have xvid 1.0 installed but I doubt that 1 pass (either 100%quality or quant=2) encoding was removed there. You just need to select the correct mode and quality/quantizer. The registry settings for xvid 1.0 was changed so by default GK tries to put value for 1 pass 100% for dev-api-3, but now it has to be always adjusted for comptest.

P.S. note that for encoding with gk 0.28.7 its enough to set defaults with correct passes just once - they will always be used afterwards.
(but there is no defaults for comp test, so it can't be saved/restored).

[LigH]

Of course, 1-pass with 100% quality may work the same way. So there shall be 2 ways to achieve the same result. I'll try that soon...

[jp80]

Well doom9 released just yesterday a guide for xvid 1.0 and GK 0.28.7 . But I dont understand and wonder why does it cover only the 2nd way of the guide for previous versions of xvid, i.e Gordian Knot / Virtualdub, and not the 1st way too, i.e Gordian Knot (see both ways here: http://www.doom9.org/xvid-guides.htm)?

[birdy]

Can btw anyone here explain why Gknot is not able to open Avi files that have been encoded with Xvid beta1 and 2>?

Files compressed with older versions open fine!


Edit:
I have to rectify the question!
If XVID beta1 or 2 installed then GKnot is not able to open any xvid file!
But if older XVID installed then GKnot can open even ones encoded with beta1 and 2!

[jonny]

@LigH:

Why not using "Enc"? :)

PS:
Using a quant=2 encode or a 1st pass unchecking "Discard first pass" gives exactly the same results.

[LigH]

What is "Enc", a new encoding tool, made for 2-pass conversions? If so, I think I slightly remember... If not, searching in more than 150 hits will become too expensive for me, so please help.
__

I recently realised that there is no "quality/quantizer based 1-pass mode" in XviD 1.0 / dev4api (choosable from the main dialog). So what do you prefer:

a) unchecking 1 checkbox;

b) selecting and typing into least 4 of 6 edit fields?

And don't make the mistake and enter {2..2}/{2..2}/{2..2} as quantizer ranges when using B frames: The default settings (factor 1.50, offset 1.00) would instead result in {2..2}/{2..2}/{4..4}!

[len0x]

Originally posted by LigH

I recently realised that there is no "quality/quantizer based 1-pass mode" in XviD 1.0 / dev4api (choosable from the main dialog).


Seriously? I don't believe that...

[LigH]

The combobox only has 3 modes:

- Single pass
- Twopass, 1st pass
- Twopass, 2nd pass

In "Single pass", I can only chose a "Target bitrate (kbps)".

[len0x]

that is a major bummer!
Can someone from regular xvid gurus confirm that?

It kinda throws to hell all comp checks used in many automatic tools! :(

Not mentioning that I just implemented Quality based encoding for AutoGK and if xvid 1.0 does not support it then I have to remove it :(

[jonny]

@LigH:
It's in my signature :D


I recently realised that there is no "quality/quantizer based 1-pass mode" in XviD 1.0 / dev4api (choosable from the main dialog). So what do you prefer:
...


I'm not sure i'm understanding all you write, anyway:

Select a zone, click "edit", change the "Rate control" from "Weight" to "Quantizer" and you have quantizer encoding.

Or:

You can also choose "Twopass - 1st pass" and uncheck "Discard first pass", you should obtain the same result as a q=2 encode (not tested this with XviD 1.0, but i bet works as the previous versions).

Or:

One pass with br=10000 :D (untested but should give *almost* same results - depending on the min-quants you configure)

[LigH]

Originally posted by jonny
@LigH:
It's in my signature :D

:cool: - Me, blind...
__

Originally posted by jonny
Select a zone, click "edit", change the "Rate control" from "Weight" to "Quantizer" and you have quantizer encoding.

:cool: - Me, blind again... I'll look there a bit closer next time
__

Originally posted by jonny
You can also choose "Twopass - 1st pass" and uncheck "Discard first pass", you should obtain the same result as a q=2 encode (not tested this with XviD 1.0, but i bet works as the previous versions).

That's what I proposed.
__

Originally posted by jonny
One pass with br=10000 :D (untested but should give *almost* same results - depending on the min-quants you configure)

:scared: Not with me, my dear... :devil:

[LigH]

Using "Single pass" is not possible for the CompCheck:

- Select "Save & Encode"
- Set up the Codec
- Select "Single pass"
- Set up zone to QF=2.0
- Press "OK"

a) Call the codec setup again: "Twopass, first pass" is selected! :eek: (Zone: QF is still 2.0)

b) Try anyway: CompCheck writes only drop frames! :eek:

So, "Discard 1st pass" seems to be the only option.

[jonny]

Some tests with a 1000 frames clip, using Enc.



Tests "with quant=2"

All default, but:
Encoding type = Twopass - 1st pass
Discard first pass = unchecked
Final video size: 35,635,922 Bytes

All default, but:
Zone/Rate control/Quantizer = 2.00
Final video size: 35,635,922 Bytes

All default, but:
Target bitrate (kbps) = 10000
Advanced options/Quantization/Min I-frame quantizer = 2
Advanced options/Quantization/Min P-frame quantizer = 2
Advanced options/Quantization/Min B-frame quantizer = 2
Final video size: 35,484,028 Bytes



Tests "with quant=3"

All default, but:
Zone/Rate control/Quantizer = 3.00
Final video size: 23,837,695 Bytes

All default, but:
Target bitrate (kbps) = 10000
Advanced options/Quantization/Min I-frame quantizer = 3
Advanced options/Quantization/Min P-frame quantizer = 3
Advanced options/Quantization/Min B-frame quantizer = 3
Final video size: 23,787,907 Bytes



a) Call the codec setup again: "Twopass, first pass" is selected!

GKnot probably reset the value (this doesn't happen in a "normal case" - for example configuring the codec with VDub).
I've an old GKnot version installed so i can't verify.
Anyway i think len0x will confirm this.


So, "Discard 1st pass" seems to be the only option.

With the current GKnot, probably yes.

[len0x]

Originally posted by jonny
GKnot probably reset the value (this doesn't happen in a "normal case" - for example configuring the codec with VDub).
I've an old GKnot version installed so i can't verify.
Anyway i think len0x will confirm this.


yes, because I can't determine if codec configuration dialog was opened and proper pass was set or not... Idea was to have comp check working even if user doesn't know anything about codec configuration.