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Topic: XviD - These are the best settings for quality (Read 30694 times) previous topic - next topic
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XviD - These are the best settings for quality

Hello 

The correct information on XviD settings comes from the few developers (often when they are contributing to forums) - this information gets rewritten and distributed on the forums and personal guides etc (type VHQ into Google or most forums and you will be told that you MUST use VHQ to increase the quality - not true in my case - if you read the explanation of VHQ given by one of the developers).

Everyone has their own objectives in using XviD (fitting video onto CDs etc). I have my own specification (below) and I would appreciate it if people could comment on whether I am 'getting it right'. I am fully aware of posts asking for best settings - firstly, I believe I use the best settings and am yet to see anyone else listing them, secondly, if we are not arguing about what the best settings are, there are only a few other things to talk about... I would like help from other XviD users who have also spent time researching. Please correct me so I get better - Thanks!

My specification:
I have 480GB of hard disc space and a DVD writer - filesize is not an issue - I am only interested in quality i.e. a perfect(!) conversion of MPEG-2 to MPEG-4.
The XviD should be significantly smaller than the original MPEG-2 (otherwise the MPEG-2 may as well be kept).
I encode everything at 640 pixel resolution (640x480 or 640x352).

When file size isn't an issue, quality is mainly about the quantizer. The ultimate quality setting (using 1-pass with the quantizer set to 2) produces a 4:3 video file that is nearly as large as the MPEG-2 version.

Therefore, I think the following are the next best settings within my specifications - please add comments

A 2-pass encode:

Key frames (I-frames) are encoded with a fixed quantizer of 2 (max = 2, min = 2).
Delta frames (P-frames) are encoded with a fixed quantizer 3 (max 3, min = 3).

Quantization = MPEG - There is a high bitrate so the picture will be sharper than H.263
Quarterpel = On - The bitrate is high enough to warrant using Quarterpel
Motion Search Precision = 6 - The best quality   
VHQ = Off - This was the hardest to find out about. Nearly everywhere states it MUST be used as it gives better quality. Not correct  - as one of the developers quoted: VHQ doesn't change the quality - it reduces the bitrate at a fixed quantizer Syskin at Doom9
As quality is reduced it is not used.

Chroma motion = On - Acts as an extra motion search precision
Keyframe spacing: 25 - One I-frame per second (PAL)

All other settings (GMC, lumimasking etc are to reduce the bitrate further with a slight quality reduction - they don't meet my specification so none are used).


That's it - thanks for reading. Now please add your opinions!   

Skywalkerjen

XviD - These are the best settings for quality

Reply #1 –
A couple of comments, first there is no best settings you will never find any settings that work universally well on all movies.  Secondly, your information on VHQ is incorrect.  It does not reduce bitrate at a fixed quantizer.  In the first implementation of VHQ it did but it was found that a lot of times this did reduce quality.  So syskin implemented VHQ so that it is rate distortion based so it will always increase quality as well as lower the bitrate.  Also if you are encoding from a dvd you may use higher than 640xX you can crop all the black borders and encode anamorphically if you don't care about how big it gets.  Generally I like to encode at about 704xX.  I crop the black borders and resize it with lancosresize.  I find this works well for me and it is a fairly decent compromise.  Also quality is not mainly about quantizer; I can show you lots of frames which have been encoded with quant 2 and look like they are about quant 31, shocking?  Not really.  Also I can further confuse this by using custom matrices, and make quant 2 like quant 1 and so on and so forth.  Forcing all the quants to 2 and 3 is very very bad when you use 2 pass if you use two pass you must let it do it's job.  If you constrain it like this there is no way it can.  You may get constant quants (acutally probably not) but more likely it will be constant crap.  XviD will not be able to make any of the right decisions it wants to make.  If you are concerned about some frames with really high quant let me assure you this doesn't happen often.  Usually when I encode a movie almost all like > 90% of quants are below 5 with none above 8 and this is without restricting XviD's max min quant whatsoever.  Your other settings aren't bad although usually mpeg matrix isn't noticable sharper than h.263.  Also there is nothing wrong with encoding at a one pass constant quant if you have the space to deal with it .  GMC doesn't reduce quality then again it doesn't increase it a whole lot either so it is better to leave it off in most cases since it is slow.  And chroma motion searches the chroma plane for a MV I believe.

XviD - These are the best settings for quality

Reply #2 –
Quote
filesize is not an issue - I am only interested in quality i.e. a perfect(!) conversion of MPEG-2 to MPEG-4.
The XviD should be significantly smaller than the original MPEG-2 (otherwise the MPEG-2 may as well be kept).

That is a hell of a contradiction. Its a conversion, so there will be q quality loss, no matter what. It is very easy to make the encoded video exceed the original MPEG2 filesize by far and still it won't be superior to it.

As filesize IS of concern to you, and considering the unavoidable loss of quality, IMO you should take the aproach of sacrificing only as much quality as you are willing to, plus using the bitrate economizing techniques both in the codec settings as well as in image processing.

I'd be encoding the video at full anamorphic resolution, aplying cropping as needed, using the AviSynth method with fluxsmooth to filter out noise (i've seen cases were this halved filesize when using fixed quants). As for the XviD settings I'd be using h.263 (people will tell you to use MPEG or custom but I preffer h.263's cleaner image) and I'd be definitely tinkering with the b-frame settings, as it's THE bitrate saving technique. Yes they will lower the quality as well, but you can reduce this loss lowering the b-frame quantizer (I use ratio 1.0 and offset 1.0, so b-frames get quantizer 3 if I encode with fixed quants 2) and by tweaking BVOP sensivity (for more or less b-frames - normaly they represent more than 50% of the videos frames).

Oh, and I don't see a point in doing 2-pass if you don't have a target size.

You should make some tests to decide what is still "perfect" for you.
Tell us what you used in the end 

XviD - These are the best settings for quality

Reply #3 –
Quote
Keyframe spacing: 25 - One I-frame per second (PAL)

Sorry, but this is just wrong. You wont gain anything with this, other than faster seeking, but the filesize would be significantly larger.

I would also suggest to use b-frames with ratio and offset both 1.0. The quality degradation is hardly noticable, but it would bring a good filesize gain.

I don't agree with Raptus, mpeg matrix is better for high quality encoding. VHQ mode 1 is also recommended imo.

XviD - These are the best settings for quality

Reply #4 –
Thanks for taking the time to make such detailed replies - much appreciated!

Quote
(In regards to keyframe spaceing at 25 frames) Sorry, but this is just wrong. You wont gain anything with this, other than faster seeking, but the filesize would be significantly larger.


No problem - faster seek time is what I am after - can't stand the wait so this I am fine with.


Quote
That is a hell of a contradiction. Its a conversion, so there will be q quality loss, no matter what. It is very easy to make the encoded video exceed the original MPEG2 filesize by far and still it won't be superior to it.


I could have been more precise but I don't think it is a contradiction. MPEG-4 is supposed to be of similar quality to MPEG-2 but at lower bitrates. I am not interested in gettting the file as small as possible - just significantly smaller than a VOB file - you can do this but still have a pretty large file!

Quote
Oh, and I don't see a point in doing 2-pass if you don't have a target size.


I am in effect doing a refined 1-pass encode. 1-pass specifies one quantizer for all frames. I am just refining that by specifying one quantizer for keyframes and one quantizer for delta frames. I have done some tests and can't see this is possible in any of the 1-pass encodes - that is why I do 2-pass without setting a desired filesize.

Quote
Forcing all the quants to 2 and 3 is very very bad when you use 2 pass if you use two pass you must let it do it's job. If you constrain it like this there is no way it can.


From numerous tests the codec is trying to encode everything at Q2. To let it do its job would be to not limit the desired filesize. When you do this it encodes everything at Q2. Forcing the quants to 5 and 6 for example would definitely be a bad idea, but forcing them to their maximum is not holding back the codec - only preventing me reaching a desired filesize - which I'm not. And setting them to quant 3 is the only way to meet my "smaller" filesize spec.


Thanks for the info on VHQ- that was exactly what I was after - I will alter the settings to VHQ1 I think. Other info I read about VHQ then was that VHQ1 did increase quality while VHQ2-4 just reduced the bitrate. My Syskin quote was obviously an older one. Thanks for the update (by the way, am I correct about VHQ 2-4?! I read about their use in another forum and that explanation (could) fit with what you said...

Thanks guys

Skywalkerjen

XviD - These are the best settings for quality

Reply #5 –
hmm.  i have a friend who's considering "future-proofing" digibeta masters (it seems likely that mpeg-4 will be in the next-generation DVD spec) by encoding 9.8mbps mpeg-4 with a standalone box.  i would consider this a better way to go about getting the best quality in mpeg-4 then transcoding a DVD.  or course, not all of us can get hold of studio released DigiBeta masters 

if you have a DVD burner, then there's no problem with burning DVDs is there?  if you're worried about the problems of only being able to burn DVD-5 (for now), you could use ReJig or equivalent transcoding software and re-author your discs.

burning DVDs is probably the better way to go... save all that hard disk for your movie projects =)

XviD - These are the best settings for quality

Reply #6 –
Quote
I am in effect doing a refined 1-pass encode. 1-pass specifies one quantizer for all frames. I am just refining that by specifying one quantizer for keyframes and one quantizer for delta frames. I have done some tests and can't see this is possible in any of the 1-pass encodes - that is why I do 2-pass without setting a desired filesize.


You can lock quants for I/P/B-frames in all modes. And if You do lock both I- and P-frames (b-frame quant being dependant on I and P quants), 1st pass info has no relevance because you don't let the codec distribute quants (bitrate) as it should, so it doesn't make sense to do a second pass. Agree? With locked quants the final size would be the same for any desired bitrate you enter...

Yes, I definitely recommend using at least VHQ 1.

Tommy, a reason I don't use MPEG matrix is because qpel + MPEG results in the infamous "moving wall" effect, and I don't want to miss qpel.

XviD - These are the best settings for quality

Reply #7 –
Raptus, yes exactly if you set that b-frame formula you will get b-frames at the quant you want as well as p-frames and i-frames at the quant you want, then you would use a constant quant 1 pass.  This is the best way to do this sort of thing.  As for the moving walls thing, it _doesn't_ happen because of mpeg matrix + qpel causes it; it happens in spite of it.  If you encode with h.263 you will notice it as well but less so.  The difference being that the artifacts which h.263 produces is more blocking whereas mpeg will produce more mosquito noise.
EDIT: BTW from PSNR tests I have seen and from ones I have done VHQ1 does increase PSNR approximately as much as VHQ4 does of course it varies but usually 4 will give a smaller size as well, so in your case 1 would be a good choice since you obviously don't care about filesize.  To get the b-frame quant to equal three here is what you do, you use this formula bvop quant = (AVG(past+future quant)*quant ratio + quant offset.  So if you want quant 3, 3=2(quant ratio) + 1 ie quant ratio will equal 1.

XviD - These are the best settings for quality

Reply #8 –
Quote
Raptus, yes exactly if you set that b-frame formula you will get b-frames at the quant you want as well as p-frames and i-frames at the quant you want, then you would use a constant quant 1 pass


That doesn't work - you can't individually set the I and P frames separately in a 1-pass encode - I have tested this. Is there some other way?

I quite agree it makes no sense to do a second pass - second pass is to let the codec decide things and I am not. However - don't see any other way of distinguishing between key and delta frames.

Not too clear - sorry. I mean I set separate quant levels as before, but the encode is always a constant quant of whatever the P-frame was set to. This is checked by filesize and also using Classic Media Player with the visualisation on to display quant settings in frames.

XviD - These are the best settings for quality

Reply #9 –
You shouldn't really care about the i-frames having a quant higher than the p-frames.  In fact you will get higher quality if they are the same trust me.  I do understand what you are trying to do.  Generally, you don't want too many i-frames either since they are lower quality than p-frames, which is why it isn't a bad idea to crank up the keyframe interval to 250.  Hope this helps.
EDIT: BTW there is no way that I can see that you can set the p-frame quant to 3 and b-frame quant to 3.  I think it would be not a bad compromise to do a 1-pass constant quality at quant 3 and use a b-frame quant ratio of 1 and use less i-frames say 250, more i-frames is not going to help your seeking enough that it will be really noticeable at all.

XviD - These are the best settings for quality

Reply #10 –
Thanks Bonzi

I thought that the key frames were the important ones and had to be higher quality than the other frames as the other frames are built from them.

Setting keyframes to every 250 will give me a seek time of 10 seconds or less shouldn't it?

Is the fact that quality is best if I and P frames have the same quant the reason why you can't set separate values for them in 1-pass?

Your help is much appreciated!

Skywalkerjen

XviD - These are the best settings for quality

Reply #11 –
Well you have to have some keyframes but from what I understand the reason why a i-frame is generally lower in quality is because it does not reference anything.  Sure future references can be made from it for p-frames and b-frames but you don't reference anything before.  Which is why you want them on scenechanges.  Your seek time should be very small ie less than 1 sec even with keyframes at 250.  Yes the max time between the keyframes is 10 sec but your computer does not take this long to jump to the next i-frame it is not real time that is the whole point of seeking .  BTW it is likely that you will get a i-frame less than the maximum i-frame ie scenechange or whatever.  The reason why you can't scale the i-frames and the p-frames quants seperately is probably because it isn't that useful really.  I mean you don't have that many i-frames in relation to p-frames anyway so why would it matter if you can change the quant for a few frames anyway?  I suppose you could get a little better quality if you i-frames were a little lower quant when you have to use them but really it doesn't matter much because of there aren't that many.  Another reason why nobody has seperated them for 1 pass quantizer is because you can get away with a little higher b-frame quant on some frames than others; this may sound a little silly but really if you are doing 1 pass quantizer you want exactly that.

XviD - These are the best settings for quality

Reply #12 –
Quote
I encode everything at 640 pixel resolution (640x480 or 640x352).

As the mods here told you already, thats not a wise idea if you are after perfect quality. Make anamoprphic encodings and use cropping only, no resizing filter. Some light additional noise filtering can be used if the source DVD is pretty noisy ....

XviD - These are the best settings for quality

Reply #13 –
Quote
Generally, you don't want too many i-frames either since they are lower quality than p-frames, which is why it isn't a bad idea to crank up the keyframe interval to 250.

Pardon me, but this seems a little nutty.  AFAIK, an I-frame defines the beginning of the GOP, and all other frames within the GOP referrence the previous I-frame. With a setting of 250 on a fairly static scene you could actually get 250 frames before the next I.  That would be sucky seeking if you wanted to chop a clip out for some reason.  Using more I-frames is only a benefit to quality the way I see it.

Perhaps I'm wrong.
Gur svggrfg funyy fheivir lrg gur hasvg znl yvir. Jr zhfg ercrng.

XviD - These are the best settings for quality

Reply #14 –
Using more I frames is not a benefit to quality.  I frames and significantly larger then P frames and even larger still when you them compare to B frames.  To many I frames will decrease the quality of the video, or drastically increase the filesize, depending on the codec and settings.  If it's a 2 pass encode, it will probably drastically reduce quality.  250 is a good setting.

XviD - These are the best settings for quality

Reply #15 –
A thread entitled like this one can lead to no good (except if it was meant ironically) and so it seems. If you want to use XviD in a way as to maximize the quality (given the limitation of filesize) all you have to do is read everything sysKin has ever posted over at forum.doom9.org. Because he actually knows how a codec works. That is all. Not pure accident and not even testing of all the possible settings are a substitute for technical insight.
As a little hint: You gain much more from a good high-bitrate matrix than from limiting your quantizers.  Or from using less B-frames, fiddling with the B-frame quant ratio or even setting ludicrously many I-frames (quoting sysKin: "You don't want I-frames.").

Really, forget all that, load the defaults and then go through sysKin's post.

XviD - These are the best settings for quality

Reply #16 –
Quote
A thread entitled like this one can lead to no good (except if it was meant ironically) and so it seems. If you want to use XviD in a way as to maximize the quality (given the limitation of filesize) all you have to do is read everything sysKin has ever posted over at forum.doom9.org.


I don't think so - it is an entirely legitimate question. I notice from trawling through these forums that very few questions are actually answered. The only people who "really know" are syskin, Koepi etc, who develop the codec but are too busy to provide the documentation. This I have little problem with - it is free and they are very active in the forums.

As an example, I have read most of the leading forums on VHQ. I am none the wiser on what it is for, nor do most of the people who comment on it - usually contradictory. I am well aware that there is no such thing as perfect quality, but under the specification I have provided there is - the codec has a finite number of settings.

Quote
You gain much more from a good high-bitrate matrix than from limiting your quantizers


By limiting the quantizers to maximum they have the highest possible bitrate to work with...

Quote
Or from using less B-frames, fiddling with the B-frame quant ratio


I don't use B-frames as I believe they are used for extra compression - not relevant in my spec.

Quote
(quoting sysKin: "You don't want I-frames


You do if you want seek points - you only don't if you want as much compression as possible - again I don't want that - I already explained.

Quote
Really, forget all that, load the defaults and then go through sysKin's post.


I have been through most of sysKin's posts on Doom9 already. They are mainly concerned with maximum compressiblilty - the point of the codec. They certainly don't terminate the threads, leading me to believe that the answers are often individualised and don't answer everyone - hence my question.

I am fairly certain I am correct with my setting though as the help provided here has not convinced me otherwise - so thanks very much for all your time guys - especially Bonzi and Raptus for the repeated follow ups.

Best regards

Skywalkerjen

XviD - These are the best settings for quality

Reply #17 –
Okay, Skywalkerjen, let's clear up some misunderstandings.

First of all, I cannot believe you that you could have read all that the 'wise' people say on doom9.org and haven't learned from that. Simply because I'm in the same position as you: I am no developer with deep technical understanding, nor do I have enough time at hand these days to read everything everyone posts. But sysKin (if we restrict it to him) has said very clearly what to make of VHQ, and if I could understand that, you can, too. (Put shortly, VHQ always enhance compressiblity and quality!) Maybe you were confused because this was not so with an early version of VHQ. The same goes for GMC (which only really helps when used in combination with VHQ). The higher the VHQ the better. Use as much as you can endure.

Second, and more importantly. You, as seemingly a lot of people, are suffering from a ambiguity in your understanding of video-compression. You have understood that uncompressed is better than compressed and that something looks all the better the less it is compressed. Good. But you've also heard that a codec is all the better if it compresses better. Now what?

Your first notion is true because it is simply a theoretical truth. In so far as a lossless compression must by its very concept always give you higher quality than a lossy codec (like XviD). BUT all this is fine, but you don't want to convert a 6-GB compressed (=lossy) DVD into a 12 GB (=lossless) encode because there's no practical gain from that. The misconception now starts when you  find yourself for practical reasons forced to choose a lossy codec but because of your 'the bigger the better'-notion are afraid to use features of this codec which claim to give 'higher compression' (=smaller and worse?). This is wrong. Smaller is not worse if it exactly fits the size you can spend for that file (2 CD-Rs?). You don't want anything that is bigger than these two CD-Rs!

Now how do you attain that goal. Following your concept of how video-encoding should be done, you'd disable all features of the codec which you find distrustful because they are known to deliver 'higher compression' (=worse quality????). Then you look how big the file grows, find it too big and downsize your output-resolution accordingly till the thing fits onto two CD-Rs without looking too ugly. That's the way we did encodes years ago with MS-MPEG4v.2 where you couldn't really influence bitrate at all... Excuse my a bit sarcastic way of describing that, but I do that in order to make argumentative faults hopefully clearer.

The better way to do this, would have been to enable all the features which yield better compression (= smaller filesize without a noticeable degradation of picture quality!) and pump-up your resolution to the maximum till you reach the best compromise in resolution-quantizer ratio. If you still have some air (quantizers at full resolution at 3 or lower) use a high-bitrate matrix like Didée's 'six of nine' matrix and get a real boost in quality. Be aware, 'six of nine' at quant 3 looks much better than the standard MPEG-matrix at quant=2 (which always looks worse than the 'psychologically enhanced' HVS-best matrix, by the way)

I.e., if you want to do what you said in your first post, you don't resize at all but crop to a mod-16 resolution and encode anamorphically with HE AAC sound and put it into an MKV-container.

Gain a visible visual quality improvement at the cost of a not noticeable higher compression. If downsizing resolution was the key to effective video compression, there wouldn't be a need for further codec development.

Really, if you deactivate any feature of MPEG-4 Advanced Simple Profile (b-frames, quarterpel...) in XviD, you could as well encode with MPEG-2. There's absolutely no excuse for doing that, it only made sense for as long as some of these features didn't actually work properly. Now they do.  Enjoy all of them. 

...and all this learned just from reading posts from the 'right kind of people' at forum.doom9.org. Cool, ey?

XviD - These are the best settings for quality

Reply #18 –
bonzi;
Quote
Also quality is not mainly about quantizer; I can show you lots of frames which have been encoded with quant 2 and look like they are about quant 31, shocking? Not really

no,you most certainly can't!
quant 2 look exaclty like quant2;excellent;31 always look like shit....
but ok,we're talking xvid after all;anything can happen..(  )
but i think you misread the stats,graph or something if you claimed this;i think you can't prove this!
i never saw quant2 lookin' bad,and i seen a lot....2 is just doing (almost) the least compression of particular frame,so your claim can't be correct....
sorry mate...
grab drfanalyzer and tell me if i was right....
http://www.geocities.com/analyzerDRF/

@skywalker;don't worry about tg;he's xvid mod over at doom9,after all...(  )
one more thing;koepi is not codec dev;he just compiles the codec...
(and if you asked this at doom9 he would flame you to death!)


but let's see if we can be of any help..(rather than discussing stuff that you don't care about;all these folks do 2-31 and you don't care about it;i don't too...)

what is your objection to the quality of the video?

what resizer are you using(and why are u resizing at all?)

1second KF spacing?be aware that many of the mpeg4 advances over mpeg2 are in the way it does motionestimation and how much KF's are spaced(ie. it can space KF more because fo more precise m.estimation)
you may leave it at that,but tdon't be surprised at filesizes or quality;
usually mpeg4 does 10sec spacing or scene change(whichever comes first)...

i-frame quant 2-2?nope,i wouldn't do that either;it seems to be that newer mpeg4 codecs(xvid too) are tuned so that i-frame quants selected  stays tuned with surrounding p-frames(btw. i support your decision to avoid b-frames...)
ie codec won't compress all p-frames with qunt2 and then use 31 for ever i-frame...

VHQ?actually on my analog stuff i didn't saw it do anything....

and after all,mpeg4 is only perhaps 10-30% better than mpeg2,and you surely "tweaked" those settings to get them as close as possible(  )

if you're interested in constantquant comparisons(so called constantquality encodings),see this
http://www.aussievideosearch.com/cmpeg4.htm
off course,it may not work for you...he's doing quant4 after all...(and getting pretty big filesizes on hires...  )

but again this is doing it the blind way;what is the issue you're not ok with on xvid?
best settings i never use would be p-frame 2-2....

anyway,tell us more,or no help for you(  )
as far as i'm concerned you may be doing crappy bilinear resizing and coming here asking questions about poor codec perormance on 3-3..and that doesn't speak well about you....not kidding...

also,if one codec is not good enough,there are other codecs,but first you should be able to say what's wrong with this one;you know,there's something AWFULLY wrong in asking "is this good,is this best" as if you don't actually watch your video....
(everyone knows i'm no xvid fan,but when you accuse it about something,please explain it....usually folks say xvid works well on clean (dvd) sources......)


and as a supplement(completely unrelated to this thread) why is h263 bigger in filesize than mpeg matrix?
http://neuron2.net/ipw-web/bulletin/bb/viewtopic.php?t=372

edit;must comment this from tg;
Quote
Really, if you deactivate any feature of MPEG-4 Advanced Simple Profile (b-frames, quarterpel...) in XviD, you could as well encode with MPEG-2. There's absolutely no excuse for doing that, it only made sense for as long as some of these features didn't actually work properly. Now they do. Enjoy all of them.

...and all this learned just from reading posts from the 'right kind of people' at forum.doom9.org. Cool, ey?

[personal attacks removed][/personal attacks removed]

XviD - These are the best settings for quality

Reply #19 –
[personal attacks removed][/personal attacks removed]

XviD - These are the best settings for quality

Reply #20 –
Quote
if you're interested in constantquant comparisons(so called constantquality encodings),see this
http://www.aussievideosearch.com/cmpeg4.htm
off course,it may not work for you...he's doing quant4 after all...(and getting pretty big filesizes on hires...  )

Thanks, interesting read. I happen to be interested in full size ~q4 captures as well.  (The test is a little skewed though, because of huge bitrate differences.)

Quote
and as a supplement(completely unrelated to this thread) why is h263 bigger in filesize than mpeg matrix?
http://neuron2.net/ipw-web/bulletin/bb/viewtopic.php?t=372

Wow, I didn't know that. I always thought that h263 was trading lower bitrate for sharpness. Nice to see a Powerdesk user.

XviD - These are the best settings for quality

Reply #21 –
Thanks for your reply i4004

I am unsure which resizer to use yet - I was told Lanczos, but reading elsewhere in other apps, lanczos is not too good? I am after a sharp one though as the XviDs will be watched on a TV which will smooth the image anyway.

Quote
i-frame quant 2-2?nope,i wouldn't do that either;it seems to be that newer mpeg4 codecs(xvid too) are tuned so that i-frame quants selected stays tuned with surrounding p-frames


Yeah - I tested that with the one-pass modes and the I-frames do just match whatever settings the P-frames were put at.
But this 2-pass method does seem to separate the I-frames quant from the P-frame.


Quote
also,if one codec is not good enough,there are other codecs,but first you should be able to say what's wrong with this one;you know,there's something AWFULLY wrong in asking "is this good,is this best" as if you don't actually watch your video....


I suppose I am asking this because I plan on using the XviDs in many years to come - the time it takes to encode them all they had better last that long. I am checking if there are theoretical improvements I can't see on my current set up but which will be evident in 20 years time when my home entertainment system is converting the XviDs to 3D...

Thanks for the links too

Skywalkerjen

XviD - These are the best settings for quality

Reply #22 –
As you don't seem to care about filesize-limitations at all, the old 're-encoding is evil' phrase applies and you should keep the DVD as it is and split it onto two DVD-Rs. Any re-encoding means another loss and without filesize restrictions you lack any rationale for re-encoding

Edit: And a 720x..., B-frame (2/1/1.5), GMC, VHQ=4 (what you call 'pushing to its limits'), high-bitrate matrix encode with quants 3-5 will look much better than a 640x no-B-frame, VHQ=1 encode at constant quant=2...

XviD - These are the best settings for quality

Reply #23 –
Quote
no,you most certainly can't!
quant 2 look exaclty like quant2;excellent;31 always look like shit....
but ok,we're talking xvid after all;anything can happen..(  )
but i think you misread the stats,graph or something if you claimed this;i think you can't prove this!

I can prove this, it would not take very long to find some frames that look bad even at quant 2 and this is not an XviD problem you probably could do this with any codec.  But you must realize it is a little exaggeration on my part too I didn't actually mean that it looked exactly like quant 31 you can't even really define what quant 31 actually looks like, I just was saying every once and a while you can find a frame with quant 2 that looks poor.  t.g.deck is right though if you have access to a DVD burner just split it onto 2 DVDs or try and make it fit onto one without reencoding anything.  There isn't any point in making mpeg4 files which are the same size as the original mpeg2.

XviD - These are the best settings for quality

Reply #24 –
Thanks for the reply t.g. deck

Quote
As you don't seem to care about filesize-limitations at all, the old 're-encoding is evil' phrase applies and you should keep the DVD as it is and split it onto two DVD-Rs.


I do care about filesize (up to 3/4 or so) but the main reason is to get it out of that format (menus etc) and be able to hold everything on a hard disc at as close to DVD quality as possible.

Quote
And a 720x..., B-frame (2/1/1.5), GMC, VHQ=4 (what you call 'pushing to its limits'), high-bitrate matrix encode with quants 3-5 will look much better than a 640x no-B-frame, VHQ=1 encode at constant quant=2...


And that is exactly what I am after. I shall now research those settings.

Cheers

Skywalkerjen