How useful is VHQ4 in your encodes?

[JohnMK]

If you've compared the file size of your encodes in VHQ4 vs. 1, and have the results handy in % difference, please post here. I'm trying to determine generally how useful VHQ4 is for other people.

My anecodte:

VHQ4/1: 1058MB vs. 1089MB
Hollywood-style movie, modern, clean, 2 hours long. GMC, QPel, low quants (2's and 3's mostly), hvs-best custom matrix, turbo mode, 2 b-frames with default settings, anything else pertinent that I'm forgetting?

This is a 3% reduction in file size for about a 50% reduction in encoding speed on my machine (P4 HT).

[Tommy Carrot]

VHQ4 in my experience reduces the ringing artifacts quite nicely (or at least i imagine it ), so for this reason i use it defaultly, as i find ringing very irritating.

[Blue_MiSfit]

i see it like this:
I usually let the comp encode all night. VHQ4 seems to enhance the quality of the video quite a bit for me. It really minimizes blocking and haloing. as such it is definatley worth it to me. Turning it off wont make me wake up earlier if you know what i mean.

[RadicalEd]

[edit]Redid test.
Settings are now default minus bframes, still quant 2.[edit2]Since I guess it's relevant to speed optimizations, I'm on an old Athlon tbird. 1Ghz and decoding from a helix yv12 encoded avi, for further speed info.[/edit2]

VHQ|Speed (s)|Size (bytes)|__% time_____________|% compression
0____6________3,907,584_______100%_______________0%
1____8________3,745,792_______133%_______________4.14%
2___12________3,717,120_______200%(150%)_________4.87%(0.77%)
3___16________3,708,928_______267%(130%)_________5.08%(0.22%)
4___21________3,700,736_______350%(131%)[263%]___5.29%(0.22%)[1.20%]

Parenthensese are the percentages against the previous level (normal % are against 0). The bracketed values under VHQ 4 are percents against VHQ1.

[aketon]

I have noticed some artifacts when I use VHQ4! I encoded "GLADIATOR" once with VHQ1 and then with VHQ4! After a very closer look in some action scenes, I saw that VHQ4 produced more artifacts than VHQ1! I know that this thing sounds a little bit crazy, but I couldn't believe it either! The most funny part is that when I used both VHQ1 and trellis, I had much better quality than VHQ4! That's my opinion although!

[temporance]

I have a related question: There are seven motion search precision settings and five VHQ modes. That makes 35 permutations. Add in other settings such as chroma mode, turbo, trellis and you have more than 100 permutations.

I would like to decide on a few (say four) permutations which give good performance and represent a good spread over the encoding speed / quality spectrum.

Does anyone have any favorite combinations of these settings?

TIA

[Jawor]

I can't post any numbers here, since I made no such comparison lately, but at a fixed target size I can clearly see the difference between VHQ=1 and VHQ=4. VHQ=4 is terribly slow on a Celeron 1200 MHz , but I use it anyway - it RULEZ!

[JasonFly]

I have a question about the use of VHQ.
I have an .avs which is so slow that I change my mind between the 2 XviD pass and decided to switch between VHQ1(in 1st pass) and VHQ4(in 2nd).
Regarding the speed optimizations in the first pass(i suppose they had something to do with vhq, qpel, gmc and some other slow calculations), does the VHQ number has an importance in 1st pass?

If this wasn't clear enougth, i reformulate:
Can I switch/change VHQ between two pass?

[Didée]

> Can I switch/change VHQ between two pass?

Yes. It's not 100% optimal, but the difference is minor.

1st pass is there to get the framesizes & frametypes for the 2nd pass. Since the actual size difference between VHQ1 and VHQ 4 is not that big, you can rely on XviD's rate control to compensate for it.

If you do so, it might be a good idea to alter the overflow settings a little:

1st=VHQ1, 2nd=VHQ4 - leave "degradation" at [your setting], and bump up "improvement" & "strength" by 50%.

In the opposite case, 1st=VHQ4, 2nd=VHQ1 (why ever do that? "Oh, 2nd-pass takes too long, but I have to get that train!"), do the opposite: leave "improvement", and bump "degradation" and "strength".

Personally, I won't recommend the "20/20/20" thingie - but that's just my picky preferences


- Didée

[sysKin]

Originally posted by JasonFly
Can I switch/change VHQ between two pass?

VHQ is automatically disabled in first pass - so don't worry if it was enabled in 1st pass or not, pass was identical.

Radek

[Didée]

Originally posted by sysKin
VHQ is automatically disabled in first pass - ...

... unless your 1st-pass was set up to be a zone using a fixed quantizer.

But admittedly, I was thinking within the (un-)restrictions of my usual methods, and forgot a little about the default behaviour

Sorry, Jason.

Syskin, thanks for clearing up that half-nonsense I produced.


- Didée

[JimiK]

Originally posted by sysKin
VHQ is automatically disabled in first pass ...

...if you don't choose a full quality first pass I do it at full quality, because when the file is not too big, I just keep it to burn it to DVD.
O.K., what I really wanted to ask is: can anybody confirm aketons observation? I can't imagine being that true, because there was a lot of testing and debugging going on, before Xvid was labeled 1.0. I use VHQ4, because I think it reduces swimming in the background. (Did not yet have the time to test the improvements of version 1.1 yet, but I'm rather curious about the results)
Best regards,
JimiK

[stephanV]

Originally posted by JimiK
O.K., what I really wanted to ask is: can anybody confirm aketons observation?

aketon has seen it, so he can post screen-shots no? would be helpful for everybody...

[Teegedeck]

Screenshots! Screenshots!

Seriously, when anyone claims to have discovered something startling it would be most useful if he/she posted screensots, avs-file and XviD setup.

aketon, can you please encode a clip at constant quantizer, once with trellis and vhq=1 and once with trellis and vhq=4? Then, please load the results into VDub and do some snapshots where you discover artefacts or other interesting differences.

Alternatively, if you still have both your Gladiator encodes, load them via avs ("directshowsource") so we can view the frame quantizers, too, with ffdshow's 'OSD' function. Would be greatly appreciated.

[gatormac]

Originally posted by sysKin
VHQ is automatically disabled in first pass - so don't worry if it was enabled in 1st pass or not, pass was identical.

Radek

If it is disabled for 1st pass is it disabled for single pass as well?

[sysKin]

Originally posted by gatormac
If it is disabled for 1st pass is it disabled for single pass as well?

No, just 1st pass - and just like everyone pointed out, I should have said "1st pass that is not full quality and uses weight zone".

@aketon - when was that? I don't believe that was any 1.0.x.

@all - when you compare VHQ1 vs VHQ4, don't look at filesize. I could easly re-tune VHQ to produce quite a big range of filesizes - current tuning is for maximum PSNR and it just so happens that this setting reduces bitrate at fixed quant by such a fraction. Could make it equal.

Radek

[kilg0r3]

Originally posted by sysKin
current tuning is for maximum PSNR

Which makes me nagging for a retuning of VHQ for maximum SSIM or - which would be even better - for maximaly positive subjective experience. For this we would only have to set up a test that equals Roberto's audio tests. A collection of clips encoded with different tunings of VHQ and here we go! Don't you say this would too much of a hassle

[aketon]

OK! I don't have "GLADIATOR" right now (he had an accident ), but I had done some tests with "INTOLERABLE CRUELTY", and after at some tests I still see vhq-1 and trellis to preserve more quality than vhq-4 and trellis! The codec I used to encode "GLADIATOR" was Xvid 1.0 RC4 !!!

Does anybody know how to post some the pictures???

[stephanV]

you can upload them here and then provide links or use the image tags.

(go easy on the JPG-compression or use png if you can )

[aketon]

HERE IS MY TEST!!!!!!

Codec: XviD 1.0 final Koepi
---------------------------
Settings:
---------
VHQ-1 clip:

default settings
quantizer 8
VHQ 1
trellis on


VHQ-4 clip:

default settings
quantizer 8
VHQ 4
trellis on

-----------

MY IMAGES:


sCREENSHOT 1:

ORIGINAL


VHQ-1 TRELLIS ON


VHQ-4 TRELLIS ON


If you look carefully at the trees, you will see that VHQ-4 smooths
much more than vhq-1!

Imagin now the same smoothing on a wall with a lot of detail (from stones)!
In "GLADIATOR" the differnces were even more bigger! VHQ-1 keeped all the
details in most of the action scenes in the arena on the walls, where VHQ-4 smoothed
everything!



SCREENSHOT 2:

ORIGINAL


VHQ-1 TRELLIS ON


VHQ-4 TRELLIS ON


Look at the trees near the sky again! VHQ-4 smoothes much more than VHQ-1!
Look at the grass the details! The original picture has a white thing in
the middle of the grass! In VHQ-1 is a little bit smoother! In VHQ-4 the
white thing dissapears!