Which settings to use to get quality encodes.

[SunMar]

Hi,

Right now I'm fiddling around with XviD and some stuff is pretty unclear to me, after reading several guides, Koepi's PDF and the XviD FAQ here.
Most of the stuff that's unclear to me is how exactly everything can improve and/or lower quality. At most places the description for the options tell roughly what they do, however that usually doesn't give me a clear idea on how they exactly affect the quality of the video.

That's what I want to learn though, how to make high quality avi's in acceptable file sizes. Although the effect of most options differ from movie to movie, it's probably still possible to get a good idea on when exactly they give what effect.

Currently I've got Koepi's 14032003-1 build installed and I'm going to go through all the options that are under the "Global" and "Quantization" tabs.
I don't expect everything to get answered, but hopefully most will :).
Some things I already partially understand, so I'll mention what I know about it. Please correct me where I'm wrong.

1. Motion search precision
I presume this "only" determines how thoroughly XviD should go through the video stream, with the higher the precision the better the quality (although the difference between Very High and Ultra High is perhaps unnotacible with some video streams, it's still higher or rather not lower).

2. Quantization type
H.263 softens and MPEG sharpens, with usually results in MPEG having a higher detail in lower resolutions and H.263 having less noise.
What's unclear to me about them though is what'd be best for high resolutions/bitrates? I used to just go for MPEG but now that I've read that H.263 reduces noise that seems more attractive.
Besides those two there's also modulated, which switches in the stream between H.263 and MPEG.
Modulated differs from the MPEG4 specs though so they're not recommended so I'll probably stick to that recommendation.
I did see though that ppl were taking about a combination of two things, MPEG/H.263 in the 1st pass, Modulated in the 2nd pass and combinations like that.
Why would you change the quantizer between passes and what are the (dis)advantages of doing that?

3. FourCC used
Just the tag that tells the player which codec it has to use to decode the video stream with, best to leave it at XVID I presume :).
Is the reason why you can also choose DIVX and DX50 though because all 3 comply with the MPEG-4 specs so they all should be capable of decoding the video stream?

4. VHQ mode
The "popup" text sais VHQ 1 should always make the video stream look better at the expense of a longer encoding time.
The VHQ 2/3/4 modes though could hurt quality, where the chance that they hurt the quality increases as the bit rate is lowered.
After reading that, is it safe to assume that at high bit rates the quality is most likely going to be increased rather than decreased, with the exception of perhaps one or two scenes?

5. Max/min I-frame interval
If I remember correctly from some text I read a while back, I-frames are also known as key frames.
From what I gathered I presume that I-frames are basically "complete" frames which do not "carry-over" pixels from previous frames and thus basically rebuild the screen.
The more you have of them, the faster encode errors are "fixed" again and they keep the stream in sync so to speak.
They improve quality, but they take up more space too, so too few of them can "break" the stream, but too many of them starts taking up way too much space.
I presume the default min. of 1 and max. of 300 values are sufficient for a good quality.

6. Lumi masking
It increases the compressability in very dark and bright scenes because the human eye tends notice encode errors in those scenes less.
It helps lowers the overall size, but if size doesn't matter you can just as well turn it off since (notacible or not) it lowers quality.

7. Greyscale
I think this speaks for itself.

8. Interlacing
Should be used when the input stream is interlaced aswell, otherwise it's probably a bad idea.

9. Chroma motion
The XviD FAQ sais this about it:
Chroma optimizer reduces PSNR by it's nature. The _mathematical_ deviation to the original picture will get bigger - but the subjective image quality will raise (as mentioned, the "stair step artifacts" get less).

That definantly clarified things for me ... uh not :confused:.
What's PSNR and what are these "stair step artifacts" ?
I have no idea on whether or not I should turn this feature on or off.

10. Quaterpel
If you compare two streams with the same bitrate where one uses Quaterpel and the other doesn't, the one with Quaterpel has a higher quality.
Thus usually it increases quality, but if you are aming at a specific filesize it's possible that without is better, just completely depends on the video stream.

11. Global Motion Compensation
I have no idea what exactly this does, only that it doesn't work too well in combination with VHQ.

12. B-frame control
12a. Maximum B-frames
Bi-directional frames. According to the "popup" it decreases size at the cost of quality, but it also says that it decreases noise and only maybe decreases sharpness.
Isn't less noice a good thing though :confused:?
It also says that 2-3 is recommended for most encodes, but how I can find out what would be more optimum for my encode?

12b. Ratio, offset and threshold
What do these values mean and what are good values or what is a good way to find out what good values for these for a video stream are?

12c. DX50 B-VOP compatibility
Based on what the "popup" said, it's better left turned on.

12d. Packed bitstream
According to the "popup", 2-pass isn't all too fond of this so when doing a 2-pass encode it's better to leave it turned off.

13. Quantization (min/max I/P/B quantizer)
What exactly are these quantizers, how can I determine what the optimum settings are for my encode and what exactly are P-frames?

[NeVeRLiFt]

I think it would be nice to know which settings effect speed without giving much quality in return....

I mean you can make some nice quality encodes with XviD, but if your not careful with the settings you can end up making a 3-5hr encode take over 9hrs easy maybe even 12hrs or longer with filters added.

XviD... the way encoding was meant to be ;)

[bond]

1) use the search function, you will find tons of quides and threads which will answer your questions
2) if still something is unclear or you want to share your ideas use the "newbie settings" (http://forum.doom9.org/showthread.php?s=&threadid=53136) thread to ask such questions and dont start a new one...

[NeVeRLiFt]

Originally posted by bond
1) use the search function, you will find tons of quides and threads which will answer your questions
2) if still something is unclear or you want to share your ideas use the "newbie settings" (http://forum.doom9.org/showthread.php?s=&threadid=53136) thread to ask such questions and dont start a new one...


I assume you have not read that thread... are you would know it mentions nothing I asked about in my post :rolleyes:
If you can take the time to ramble on like you did, maybe you can go that little extra and post something useful.

My question still stands ;)
Settings in XviD that effect SPEED a great deal but do not yield a great return in quality. IMHO XviD is really slow now with the wrong settings, nevermind the quality. I can produce great quality with codecs that are alot faster.

[snowbeach]

@SunMar
Most of your questions will be answered by my guide. Have a look. See my signature.

@NeVeRLiFt
Have you read my guide? ;) Otherwise produce great quality with other codecd that are faster! :D But I think, there are none! Or which are these, you use? :cool:

[SunMar]

Originally posted by bond
1) use the search function, you will find tons of quides and threads which will answer your questions
2) if still something is unclear or you want to share your ideas use the "newbie settings" (http://forum.doom9.org/showthread.php?s=&threadid=53136) thread to ask such questions and dont start a new one...

1) I have, several times. It lists tons of guides and threads yeah, but most of them do not answer my questions. Pretty much all of them just say what you have to do, not why you have to do it and that's what I'm trying to figure out. I'm not new to encoding, I've been encoding small stuff for about a year or something now and always blindly followed what some guide said, but I never got into the details which I'm trying to do now.

2) I could've done that, but since it was so long and tries to go a bit more in-depth than what's discussed in the "Newbie" Settings thread so I decided not to. That thread is mostly "What do I put here?", not "Why do I put that there?".
And if the mods don't agree they can always merge this thread into that one.

[NeVeRLiFt]

Originally posted by snowbeach
@SunMar
Most of your questions will be answered by my guide. Have a look. See my signature.

@NeVeRLiFt
Have you read my guide? ;) Otherwise produce great quality with other codecd that are faster! :D But I think, there are none! Or which are these, you use? :cool:


I can make high quality nice looking 1cd rips with DivX5 and divX3.11a both faster than XviD. I mean come on I can make a 2hr DVDrip with Nandub in 3-5hrs, with XviD and the wrong settings the same movie can take over 10hrs.

There is also Helix Producer Plus and RealVideo9 and WMV9 both work well(if you like smoothing).

[bond]

i really dont want to offend anyone but every of your questions (sunmar and nevermind) is already answered in this forum and in documents linked to in this forum.

all the knowledge people in here have, they are having because of reading this forum, so search and you will find...

but perhaps someone with too much free time is going to answer your questions although i dont know what will happen if koepi reads this thread before ;)

[NeVeRLiFt]

Good ole koepi ;)


Guess you dont know the answer there bound but can spam away and make idle threats :rolleyes:

[snowbeach]

@NeVeRLiFt

of course speed depends on your settings, but in most cases and in my case it depends on quality settings and not on wrong settings. speed also depends on your cpu system. probably an encoding on 900MHz machine will last longer than on a 3GHz machine. but it is your choice. i recommend you stay with other codecs.

[NeVeRLiFt]

Originally posted by snowbeach
@NeVeRLiFt

of course speed depends on your settings, but in most cases and in my case it depends on quality settings and not on wrong settings. speed also depends on your cpu system. probably an encoding on 900MHz machine will last longer than on a 3GHz machine. but it is your choice. i recommend you stay with other codecs.

I dont care what you recommend :rolleyes:

Thanks anyway.

[SunMar]

snowbeach:
@SunMar
Most of your questions will be answered by my guide. Have a look. See my signature.

Thnx, it looks pretty thorough. Will read it after I finish this reply ;).

bond:
i really dont want to offend anyone but every of your questions (sunmar and nevermind) is already answered in this forum and in documents linked to in this forum.

I'm not offended, I know what it's like to have newbies come in and ask questions which could be easily answered by the search button.
I didn't expect that all replies would be answers and your reply didn't surprise me either.

all the knowledge people in here have, they are having because of reading this forum, so search and you will find...

True, but IMHO there's a limit on how much time one should spend on searching. If I have a guide (snowbeach's hopefully :)) that answers the questions I could figure them all out in about 20 minutes tops.
When that's the case I do not want to spend several hours going through dozens of threads in the forum of which like 90% doesn't even come close to answering my question, but to find my answer I'd have to check them out anyways.
I spent ~30 minutes on reading the XviD FAQ, a guide and some threads I ended up in through the FAQ and some other threads that were recently replied to. After that I spent another ~45-60 minutes using the Search button to find out more information.
So, IMHO ~1h30m is plenty of time to look for answers compared to the 20m I'd need when I had a good guide, after that I decided to just post my questions.

but perhaps someone with too much free time is going to answer your questions although i dont know what will happen if koepi reads this thread before ;)

Like I said when I posted this thread: I don't expect everything to get answered.
Perhaps somebody with too much free time will answer, perhaps not, we'll see :).
I'm asking questions, not demanding answers and am satisfied with any links I'm given.

[snowbeach]

@NeVeRLiFt

ooops. quite aggrssive... :eek: :D

@SunMar
If all your questions are not answered in my guide, please post your questions in the newbie settings thread, so all interested in a good guide might help to make a better guide.

[NeVeRLiFt]

@snowbeach or anyone else who has an opinion on this...

VHQ Mode
What can anyone tell me about this and how it effects Quality vs Speed.

Lets take TMPGEnc for instance... we all know Highest Quality (very slow) does not really give much better quality over High Quality (slow) but that it can really effect the speed of the encode and slow it way down.

And please people if your gonna bother to post something, please post about what people are asking ;)

Thanks

[NeVeRLiFt]

Ok doing a test now, ripping the DVD movie of Red Lined. Its a 1hr 30min movie.
Using Nic's newest build and my AthlonXP 1800+ w/ 768mb ram and my Raid setup 240gb HD's (belive this is fast enough)

I'm using a 640x272 resolution and going for 1cd will be using VBR Mp3 for audio. I feel this DVD is not very clean and so I'm using the YATS 1.3 filter to help with noise. (I dont usually use any filters on my 1cd rips) Well since its Film source there is no deinterlacing needed. I used a Precise Bilinear filter for resizing.
Most people know bilinear for resizing to a smaller resolution and in my testing it gives the sharpest image and adds some to size.

Using these settings in XviD
6-Ultra High
New Modulated HQ
Xvid
VHQ 4
240
1
Enable Lumi Masking
Use Chroma Motion
-1 (no B-frames)
150
100
DX-50 Bvop compatible
Quants
2
31
2
31
Everything else defualt.
I told XviD to shoot for a 625mb video size.

Now this rip is looking at 20-24hrs it seems now to complete....
Nandub or DivX5 could and can do this encode in 4-6hrs no problem and have very nice quality and no problems.
Will post back after its done and comment on its quality.

What I'm looking for is what settings can I adjust that will not hurt the quality but increase the speed.

[NeVeRLiFt]

damn double post

[Pasqui]

Hi,
you should avoid Lumi Masking as it is currently buggy.
Also, New Modulated HQ should be avoided as it breaks MPEG4 specifications. I would recommend you H263 quantification matrix.
B Frames should be an option as it can help a lot for 1 cd movies. But it's up to you. But you should use 0 instead of -1 for B Frames as it uses a completely different (and probably more efficient) algo for I/P/B decision without inserting any B Frame.
To finish, you should use Koepi's latest build: its date is 14/05/03 (compared to Nic's 30/03/03), it is less buggy (hoppefully) and has a greatly improved VHQ mode.

Cheers,

Pasqui.

[Mole]

Look, there is no such thing. If you want higher speed, there'll always be quality tradeoff.

It is then up to you to judge whenever the tradeoff is noticeable enough to be worth the speed increase.

You might not notice anything, but somebody with better eyes might.

Afterall, you are encoding only ONCE, so why not spend some extra time to make it real good.

If you want higher speed, you can try these settings:

VHQ = 1
disable lumi masking and chroma motion
motion search = 0 - 5

All these will always effect the quality.

PS, the settings you used won't make a good 1 CD rip. Those looks more like a setting for a 2 CD or high bitrate rip.

[snowbeach]

@NeVeRLiFt

Try the following, as I have the same opinion as Mole. Probably this will make your encode faster and the picture better... But I know you do not care what I recommend. ;)

AviSynth Plugin 2.5
LoadPlugin("?\mpeg2dec3.dll")
mpeg2source("?\VIDEO_TS.d2v")
crop(?,?,?,?)
LanczosResize(640,272)

I would not try any noise filters, but if you like try for example...
LoadPlugin("?\mpeg2dec3.dll")
LoadPlugin("?\UnFilter.dll")
LoadPlugin("?\UnDot.dll")
LoadPlugin("?\Convolution3d.dll")
mpeg2source("?.d2v")
crop(?,?,?,?)
LumaFilter(-2)
Convolution3d(preset="movieHQ")
UnFilter(-5,-5)
UnDot()
LanczosResize(640,272)

or

LoadPlugin("?\mpeg2dec3.dll")
mpeg2source("?.d2v")
crop(?,?,?,?)
LanczosResize(640,272)
mergechroma(blur(1.3))

Download Koepi's build 14052003-1 here (http://roeder.goe.net/~koepi/), as Pasqui suggested as well, and try following XviD settings:

6-Ultra High
H.263
Xvid
VHQ 1
240 (if your source is 23.976 FPS, 250 if your source is PAL and 300 for 29.970 FPS)
1
DISABLE Enable Lumi Masking
Use Chroma Motion
Quarterpel
2 (ENABLE B-frames)
150
100
100 (THRESHOLD to 100)
DX-50 Bvop compatible
Quants
2
31
2
31
Two Pass tab.
below i-frame distance: 12 (if your source is 23.976 FPS, 13 if your source is PAL and 15 for 29.970 FPS)
i-frame bitrate reduction: 24 (if your source is 23.976 FPS, 25 if your source is PAL and 30 for 29.970 FPS)
bitrate payback delay: 240 (if your source is 23.976 FPS, 250 if your source is PAL and 300 for 29.970 FPS)
Payback proportionally
Debug tab.
Check Chroma Optimizer
Everything else default.

Same settings for the 2nd pass, of course.

You should get a nice rip... Hopefully. :D

[avih]

snowbeach, i have a feeling i'm gonna bookmark your last post ;)

[Gazza]

snowbeach

I agree with avih. Why don't you add the contents of your post to your guide as an appendix 'Suggested settings you can try'

[Andrey]

May be it is good idea renaming "DX50 B-VOP compatibility" to "Use closed GOP" to make it more understandable ?

[NeVeRLiFt]

Well its done ;)
1st pass took 11hrs
2nd pass took 9hrs

XviD was told to make a 625mb and it made a 610mb, this is 15mb under size.

Movie is 1hr 30mins and looks very good, but the time it took to make this movie is not worth it. Why take this much time to encode a movie when Nandub or DivX5 can do the same encode in 4-6hrs and give the same quality?

Well I went back and made a higher quality VBR Mp3 that was 90mb and now have a perfect 1cd rip of this movie at 700mb ;)
I'm very happy with the quality but must say XviD is very slow and makes wonder why people use it? I dont see the quality vs speed here being a good trade off....


Good day :sly:


Edit: Maybe that filter I used effected the filesize.

I watched this movie fullscreen on my Hitachi V810 21" monitor and it really looks good, on my TV using TV-out it looks so nice ;)

Now for the question!
What can I do to maintain this level of quality yet increase the speed so that it does not take over 6hrs to encode?

@snowpeach
Your settings dont seem to be what one should use if they want a high quality 1cd rip. FYI have been ripping now for over 6yrs and been banned and suspended from this dang forum more than anyone else I think :p

I posted back when koepi released his build and said it was slow. I have set back and lurked here and dont see none else mention how slow XviD is now! Well I'm telling you now its slow! Very slow and I dont feel the speed vs quality is a fair trade off.
Nandub is not slow and still gives perfection if used right ;)

I dont see why people think they have to use different settings really when making a 1cd rip, all you need to change is the resolution maybe and the bitrate for sure ;)


I have put this movie on a 100Mbit dump and will fxp it to anyone who wants it just so you know that I'm not all talk and can back up my encodes :devil:

[avih]

NeVeRLiFt, take it easy dude. your've made your point. you say that xvid is good but slow. so either don't use it, or wait for someone's answer (you can try the suggested settings u know... go for a 10 mins clip), or just experiment and find the settings that make xvid good and fast, and share them with the rest of us. but don't make so much noise. please. thanx.

[Acaila]

What can I do to maintain this level of quality yet increase the speed so that it does not take over 6hrs to encode?
Like so many have said before me, decrease/disable the VHQ level. VHQ was created to squeeze a bit of extra quality out of an encode at the expense of greatly decreased encoding speed. Clearly you're not willing to pay this price, so just turn it off completely. Without VHQ XviD should perform just like it did before -> great quality and speed roughly equal to Nandub and DivX 5 (if there's a speed decrease even with lite settings, then I haven't seen it).

Lumi Masking in its current form actually doesn't always work correctly, so it mainly just slows everything down without doing anything. Turn that off too.

FYI have been ripping now for over 6yrs and been banned and suspended from this dang forum more than anyone else I think One would expect that you understand by now how to behave in this forum. But just in case you don't, let me just inform you that you're walking on the edge again. And no, AFAIK you're not holding the record, but you are close to the top, although I doubt that's something to be proud of...

I dont see why people think they have to use different settings really when making a 1cd rip, all you need to change is the resolution maybe and the bitrate for sureDifferent people, different opinions. But I agree with you that in general you can keep the same settings for 1 or 2 CD's. Although filters can be an entirely different story ;).

I have put this movie on a 100Mbit dump and will fxp it to anyone who wants it just so you know that I'm not all talk and can back up my encodesJust to play devil's advocate here, you DO know that you're offering people to perform illegal actions by downloading that from you don't you? :devil:

[Gaia]

I posted back when koepi released his build and said it was slow. I have set back and lurked here and dont see none else mention how slow XviD is now! Well I'm telling you now its slow! Very slow and I dont feel the speed vs quality is a fair trade off

Come on are you really that stupid. You simply don't have a clue what you're talking about. Use search. Ofcourse Xvid is slow if you use every possible setting. All new and very advanced stuff. You can get very nice encoding speed and still good quality if you want. This treat should have been closed after first post. This very same thing have been discussed trillions of times already.

You should be banned again.

[Koepi]

Be assured - he _is_ banned. Too much profanity.

Regards
Koepi

[Fairlight Excalibur]

Originally posted by Acaila

Different people, different opinions. But I agree with you that in general you can keep the same settings for 1 or 2 CD's. Although filters can be an entirely different story ;).



I agree Acaila. I always shoot for settings that will give a perfect 2cd rip then use the correct resolution and bitrate to fit it to 1cd.
Filter depends on the source and how much detail you wanna trade off for size. Most movies 2hr less dont need filtering to fit to 1cd IMHO.

L8r

[Teegedeck]

Perhaps someone should just force the slowest and best VHQ and motion-search settings in his build and CME and quarterpel; dangit -- no options at all except for a target filesize! :devil:

And a big red rubber-stamp on it, saying expect your encode to take 48 hours, if you don't like it go away! :p

No, really not. But now I can actually see the wisdom in the 'quality slider' that's been proposed for the config.

[bilu]

I've read diagonally this thread, but I didn't like Neverlift's attitude :rolleyes:

I have a PIII-850 desktop and a PIII-500 laptop.

My encodings go 6 fps on the desktop and 3 fps on the laptop for each pass.

I only change the default settings on XVID to use chroma motion and
2/150/100/255 on b-frames, h.263 modulation (of course I could use MPEG :) ).

But the reason I don't use more settings to get more quality is that I think I already have enough settings activated for my machines ;)

Wish everyone would be this reasonable :rolleyes:
Bilu

[snowbeach]

@avih & Gazza

The same settings I used at this post are suggested in the guide. The only difference might be that I use VHQ1, because of the speed stuff discussed here.

Appreciate it that you like my guide guys. :)

[MoritzT]

@NeVeRLiFt

If your only problem is the speed, SHUT UP and be happy.

I couldn't complete an encode in the last 2 months. I exchanged everything on my computer, and still ......
Yet, I am still using XVID because of the results (if I get them, which I did some time ago. Might be too hot in my flat...). It's the best codec available and I I don't think you should critize the dev's for not giving you a lighting fast codec. Quality is the only thing that matters, really.
I mean, would you rather crash with a plane (which should be quite fast) or land safely and slowly?

CU

MoritzT

[bond]

come on people, make love not war :)

[thejho]

@snowbeach

quote:

LoadPlugin("?\mpeg2dec3.dll")
LoadPlugin("?\UnFilter.dll")
LoadPlugin("?\UnDot.dll")
LoadPlugin("?\Convolution3d.dll")
mpeg2source("?.d2v")
crop(?,?,?,?)
LumaFilter(-2)
Convolution3d(preset="movieHQ")
UnFilter(-5,-5)
UnDot()
LanczosResize(640,272)

I thought you had to put the resize filter before the denoising filters ?
:confused:
You also seem to say that now quarterpel is all right for 1cd rips.
I haven't heard much about it, don't know if it's been improved (not in the changelog)but I remember reading that it was not efficient at low bitrates.

thejho

[snowbeach]

some say that QPel should not be enabled, because it could increase the so called mosquito noise. but i have not experienced such problems yet. that is why i use it.

it depends on what you like, if you put the denoise filter before resizing or not...

[crusty]

Ok after all the flaming and banning I'll try to answer some of your questions SunMar:

1 Motion Search Precision
Don't know exactly what it does compared to VHQ and Qpel but the difference in speed between settings 5 and 6 is so little with the new builds that 6 is the recommended setting.

2
Modulated differs from the MPEG4 specs though so they're not recommended so I'll probably stick to that recommendation.
My opinion on this: As long as it can be played by future Xvid-codecs I really don't care if it's not fully MPEG4-compliant.
Why would you change the quantizer between passes and what are the (dis)advantages of doing that?
First pass will give you a compression result database on which the second pass determines whether to use one Quantizer Matrix (QM) or the other. The decision is based on Quantizer.
The effect of this is to produce a sharper looking movie than H263 without the filesize of Mpeg QM.
You can also produce clips with different QM's and then stick them together in the final avi/ogm/mkv.
The advantage of this is that you can use QM's optimized for different types of movie content (say, a High Quality QM for low-motion scenes and a Heavy Compression QM for the end credits), thereby optimizing size and quality even more.
It's basically a trick to improve quality at a given filesize.

3
best to leave it at XVID I presume
Yup.

4 VHQ mode
VHQ is a recent addition and is still in development. If you want zero artifacts for sure stick with VHQ=1.
I found the 03052003 build to be quite good at VHQ=4, even at low bitrates. The 14052003 build is also good but has less improvement in compressability with VHQ=4 than the previous build. On the basis of rather preliminary tests I would say stick with the 05032003 build of Koepi, and use VHQ=4 if speed is of no concern. Both at low and high bitrates

5
The default is really dependent on source, and is 10 seconds. Read Snowbeach's guide for more details.
I usually set it lower, before B/P-frame deterioration causes a visible 'pumping' effect when the next Keyframe comes by.

6
Don't bother using Lumimasking as it's broken at the moment. Same goes for GMC, it's of no use ATM.

8 DeInterlacing in third party tools like avisynth, using decomb, and in Virtualdub(mod) is MUCH more powerfull than any codec Interlacing or deinterlacing functions could ever hope to be.
If you want to leave your movie interlaced you've got to use this function.
I always deinterlace.

9What's PSNR ?
It's called Peak Signal to Noise Ratio, PSNR, and it's a mathematical description of how much the end result deviates in absolute, mathematical quality from the original. In theory, this has nothing to do with how the human eye sees the difference between the original and the end result, but in practice there is, al be it not a one on one comparison.
That's why a lot of people use PSNR to compare effects of options and filters.
Turn Chroma Motion on, it doesn't hurt and it only helps. Even more so on cartoons and Anime, but that's a long story.

10 Qpel
Due to it's nature, at a given filesize, there is NO way to tell if it's going to help or hurt compression. Just try it out on any particular clip and see. If you get undersized files, turn on Qpel anyway.

11 GMC
Don't use it. Period.

12
a: 2 or 3 B-frames are what's least likely to hurt your encodes.
As a rule of thumb, don't use more than 2 on 2CD rips.
There's quite a lot of discussion on this topic so you're not likely to find an absolute answer on this.

b: Read Snowbeach's guide, you'll find the answer I gave in another thread there.

c: Turning it off is likely to break a lot of things, so only a fool or a hero would even dare to attempt it. :D

d: idem

13what exactly are P-frames?
Short answer:
A P-frame is a frame derived only from the previous frame.
A B-frame is derived from both the previous AND the next frame.
It's the way how mpeg4 works.
You might want to check out the DivX 5 forum's sticky's. A lot of this is explained there.
Really, read the sticky's first before asking these kind of questions.

Well HTH.

May be it is good idea renaming "DX50 B-VOP compatibility" to "Use closed GOP" to make it more understandable ?
I hardly think that's gonna help any newbie. :)

I thought you had to put the resize filter before the denoising filters ?
In general, it just hurts speed if you put noise filters before resizing, because they have more pixels to work with then.
But it could help quality if you do.

[sysKin]

Info: if you want to imitate DivX5's motion estimation, set XviD's motion precision to 4. This is where XviD stops using inter4v mode (four vectors per macroblock) - exactly like DivX5 (or 4 or 3).
Compare speed after that (without VHQ and CM of course...)

Radek

[thejho]

In general, it just hurts speed if you put noise filters before resizing, because they have more pixels to work with then.But it could help quality if you do.


Hum... Interesting, I always go for the best quality, since my system allows me too (512mo, 2600+ athlon).
I'll try it.
By the way I noticed something with xvid in one of my recent encodes (unforgiven :) )on 2cds: mostly the quality is perfect,but at times while much of the frame is allright, parts of it at get VISIBLY blurred, like part of the face, a bit of a wall. It feels like it's using divx5 at a low bitrate for parts of the frame :p !

No filters used (I'll try undot since this is a little noisy dvd)
bframes threshold at 0, which I just learnt means no bframes (maybe that's why !...:devil: ).
No chroma optimiser. chroma motion ON.
VHQ-4 with 14/05 build
rest at defaults.
Bitrate: 1100


thejho

[crusty]

@thetjo

Do you get undersized files? Turn Qpel on if you do.
You can safely turn on Chroma optimizer anyway.
You could also use B-frames at conservative settings, say 1/150/100/0 or 1/150/0/0. It's completely safe at those low settings.

I also always use Undot, preferably once before and once after resizing. It does some sort of magic that improves compressabilty without affecting either quality and speed. It's a bit like salt while cooking...it just makes things taste better.

There is a sort of option that is somehow related to the specific kinds of artifacts (i.e. in faces) you get. I can't remember exactly which one though...erm. :sly:
You could try messing with the payback settings, try payback with bias.
It will give some extra bits to low motion scenes.
Do you only notice it with faces?

BTW, you might also try placing Unfilter as the last filter you use.
The resizing might undo any blurring you have done, so at least use it after resizing.

[thejho]

Nope, I don't get undersized files.
I'll try undot before and after the resizing filter, but I tried unfilter(-5,-5) and felt it was too strong. Maybe I should use less powerful settings.

This blurring problem also happens with walls,and other stuff, but never (it seems) at the edge of objects.

You're saying the settings i used 2/150/100/0 are all right?
So 0 in bframe threshold doesn't prevent their use ?

Thanks anyway !

thejho

[crusty]

B-frame threshold is about how often the codec decides to put B-frames in your movie.
soemthing like -100, can't remember exactly, is the least amount of B-frames, while 255 is the most possible.
SysKin said in another thread that the 0 setting is programmed to be the most intelligent mode of decision. So it's safe to use.
And only -1 or 0 in max number of B-frames pervents their use.

The use of Unfilter just depends on the source. Sometimes I don't need it at all, sometimes I use values of 2,2 or -2,-2 to sharpen or soften it juuuuust a little. I only used 5,5 once. I find low values make the end result look better without it looking filtered, and that's the way I like it to be.

[thejho]

Great!
I'll try it this way!
Thanks !:D

[Garfield]

IIRC, a treshold value of -100 don't allow any b-frames

Personnaly, i use comp test to see how treshold influence compressibility but i don't like going above 50.

The thing that i'm still wondering about the b-frames treshold is if it's better to have few consecutives b-frames (i.e:1)with a high treshold ( around 100 and above ) or to have more consecutives b-frames (2/3) with a low treshold

[crusty]

The thing that i'm still wondering about the b-frames treshold is if it's better to have few consecutives b-frames (i.e:1)with a high treshold ( around 100 and above ) or to have more consecutives b-frames (2/3) with a low treshold
I asked SysKin the very same a while ago...
Take a look at this thread:
http://forum.doom9.org/showthread.php?s=&threadid=48443

In it is at least a good, solid explanation of all the B-frame settings.

[unmei]

this might not interest you if you use fast computers, but more consecutive B-frames = more stress on the CPU on decoding. But imho 2 b-frames should not give much problems even my slower comp can play it, but starting form 3 the CPU usage increases very fast. I simply can't play fluent those 5 b-frames encodes some people love :(

I would go for for 2 b-frames and increase the treshold if really necessary.

referring to far above:
i found use for Lumi-Masking once i had a anime DVD with really badly washed black most of the time. i did not stretch the colorspace or the like, but turned LM on and guess what - i encoded the whole thing in quant 2 and with LM it reduced the filesize by 50% (left it as a 1-pass Q2 encode then:) . This in no way means i recommend LM, i don't use it by default, but it's a switch one could try if desperately seeking to reduce the filesize, maybe the result are better than by further increasing the quantiser.

VHQ is a absolute must imho, when i installed the first build which had it, it didn't work so i left it aside for a while, but since i tried it again in one of the later builds it worked with mode 4 and i love it ! never turned off again :) it's one of the gimmicks that makes XviD stand one step above your average mpeg-4 encoder
(er and who said nandub - one still talks about "perfect" encodes with it - must be a different religion than i belong to? ;)

[Rober2D2]

About use of Packed Bitstream in 2-pass encodings:

If you use that, you will get an oversized file. What I do to avoid that, is to activate packed bitstream only in the second pass. I had some problems with previous Xvid versions: A message in some frames reporting a "Broken B-Frame" (Written in white letters in the upper part of the frame). Latest Koepi version (14-05-2003) seems not to have this problem (At least I haven't seen it for a long while)

Advantages:
- It is much easier to edit films with virtualdub

Disadvantages:
- If you use ffdshow, you must use xvid.dll to decode, instead of libavcodec. To be truth I don't consider that to be a disadvantage.

- I don't really know if it is completely bug free.