higher quality at max quality,.. quality, comparison, difference, possible, question

andy

This is ment to be a little question about higher quality,..

I just did a little comparison of DivX5, Xvid and 3ivX and despite the fact that the 3ivX encode was abouth twice the size of the Xvid encode (about 10% larger than DivX5) I had to admit that it definatly won in regard of quality.

I just did a 3CD Matrix 3ivX encode and the quality is amazing, can't see the difference to the DVD.

So is it possible to tweak Xvid that it'll produce better quality at max bitrates ?

Cu Selur

Ps.: There's no visible ringing with 3ivX at max bitrate, with Xvid there is. So plz don't take this wrong I really love Xvid, it's just a little request for the programmers to have a look at, if they find the time.

Member of Flaskmpeg.info? Do you still use Flaskmpeg? If you do you can't compare anything.

What do you mean better quality at max bitrate? I can't understand what you are talking about.

It's again matter of taste what you think is best quality. Doing 3cd encode of Matrix is not a good way of testing. I personally like crispier, sharper more detailed picture, i don't care about few blocks here and were.

What program you used for encoding? What kind of settings for Xvid and Divx? What kind of Avisynth script you used? I have done some testing with 3ivx and got totally different results.

Basicly give more details.

Xvid@Q1 + Qpel + Chroma Motion  

What do you mean better quality at max bitrate? I can't understand what you are talking about.

i think he means that even if you set the bitrate to maximum you won't reach the quality of the dvd source. don't know how 3ivx performs at the maximum bitrate, but this seems to be a problem of mpeg4 in general.
have a look at this thread.

showthread.ph...6amp;pagenumber=2

quot;i think he means that even if you set the bitrate to maximum you won't reach the quality of the dvd source. quot;
Yup, that's what I ment,..
The main thing that bugs me, is that u still got rinningamp;co with yout encodes, even if u set the codec to max quality or the file turns out to be undersized (if u aim for a 2 CD rip, which I normaly do).

The thing is 3ivX produces a bigger file at max quality than xvid, but it also kills ringing, color/wall_movement,...

Cu Selur

Ps.: about the flaskmpeg thing:
1st I'm an admin of the flaskmpeg.info/baord (german)
2nd flask isn't so bad, atleast the newest version
3rd I used GordianKnot to create the avs file and Virtual Dub Mod for encoding,...
4th I'm also a mod at the .de forum; so may be I'm not a total noob

The thing is 3ivX produces a bigger file at max quality than xvid, but it also kills ringing, color/wall_movement,...

I disagree with that, just follow my prevoius post.

I did,..
And I just tested another movie and had to realise that not all the movement is gone, but it's a lot less visible than with xvid.

Cu Selur

Has anybody already made a test with xvid at quant 1?Are we talking max bitrates or not?

I haven't used quant 1 for a pretty long time ...

In the past, speak some months ago, I found quant 1 to be buggy sometimes, for no obvious reason. And since I saw no need for the resulting extreme bitrate, I didn't investigate since then.

Are the quant1's bugfree now?

I just selected,. quality = 100%, so it could be that xvid will still use quant 2,.. will test taht tomorrow (when I get home)

quot;Are the quant1's bugfree now?quot;
Thought it just produced an unresonable amount of data,...

Cu Selur

...just wait for H.264 implementation....
regards,george

@Selur

I read your results in other thread and your mistake was that you used new modulated quantization which is actually only h.263 when used with quantizers lower than 4 (which is most likely the case in your tests) and h.263 quantization is known to keep less details. You also used bframes which are also known to have less details than without it but you get lower filesizes. If you want the highest quality possible with XviD just use constant quantizer encoding with quant 2 and MPEG quantization (chroma motion is also nice) and I guarantee you that you wont be able to tell a difference between XviD and DVD and there also wouldn't be any ringing. If that is not enough for you and you want higher quality but also higher filesizes you should use custom quantizer matrices. You can find some good matrices here and here. Some of them are for lower bitrates and some of them are for higher bitrates. I suggest you try that HVS matrix which is attached on first post in this thread.

mfluder

Hmm,.. I did also test mpeg amp; all features of, and there was still some ringing around the cable at Morpheus head (where Morpheus is 'questioned' by Agent Smith).

Thx for the info about the different matrixes, totaly forgot them,.. (tested them a while back, but never at max quality)

Cu Selur

/edit:
just did some test, and I really like the hvs-best-picture matrix it helped a bit, but the real quality boos came with doing a 1pass-quantizer=1 encode, earlier I did a 1pass-quality = 100% encode and so I had to realize that quality=100% isn't the same as quantizer=1 (which I thought), it matches quantizer=1)

So the next question is? Is quantizer 1 buggy, and if not why isn't it used to prevend undersized files? If it is buggy, could someone plz fix it?
edit/

/edit2:
mfluder you are my man of the day, I finally found a way to produce the quality I like:
hvs-best-picture + 1pass-quantizer=1 + bframes(3/150/100)+ chroma motion + qpel + dynamic hpel/qpel; at least for the scene where morpheus is questionend (matrix chapter 28), this really is how I like it,..
edit2/

@Selur
I think the reason why quant 1 is not considered is that using quant2 and a larger image will give better quality and a smaller filesize. Not relavent to all uses, but for DVD conversion and capture archiving it is. Can I assume that you have tried post-processing on XviD?

@Selur
IMO it's an overkill to use quant 1. You'll get much much bigger filesize which is not worth the quality improvement. Also, there is a problem of a CPU usage. It's much higher when decoding a file encoded with quant 1. And most important thing is that quant 1 is buggy with current builds due to TOOSMALL_LIMIT set to 1. This will be resolved when new API is finished by setting TOOSMALL_LIMIT to higher value for quant=1 and to 1 for quantizers higher than 1. I suggest that you use quant 2 and try to find a matrix that fits your needs. If you can't find one than try making one yourself. That way you'll also learn some things about quantization.

mfluder

I have found b-frames to lower the quality of the encode quite a bit (for instance, your setting of 3-150-100)...you might want to remove the b-frames and go w/ quant. 2...this might produce better quality...just a suggestion

Originally posted by Kramerica
I have found b-frames to lower the quality of the encode quite a bit (for instance, your setting of 3-150-100)...you might want to remove the b-frames and go w/ quant. 2...this might produce better quality...just a suggestion

I don't agree with you at all. B-frames have improved all my encodes a lot but then again i haven't tried max quality. Example Matrix is ultimate b-frame movie, even with very high bitrates all my Matrix encodes(without b-frames) looked really bad but 1CD rip with b-frames and quality is simply amazing. And yes i use only 2-pass mode.

quot;using quant2 and a larger image will give better quality and a smaller filesizequot;
have to disagree with that, with quant 1 ringingamp;co are not visible, with quant 2 they are

quot;Can I assume that you have tried post-processing on XviD?quot;
yup, tried wit and without postprocessing (used ffdshow and nics decoder for testing), but I still would votefor quant 1 if it's a quality matter.

quot;and most important thing is that quant 1 is buggy with current builds due to TOOSMALL_LIMIT set to 1. This will be resolved when new API is finished by setting TOOSMALL_LIMIT to higher value for quant=1 and to 1 for quantizers higher than 1. I suggest that you use quant 2 and try to find a matrix that fits your needs. If you can't find one than try making one yourself. That way you'll also learn some things about quantization.quot;
Thx, didn't know for sure quant 1 was buggy, so I'll go to quant 2 and try to generate my own the quantmatrix.

Cu Selur

There are still some scenes (very few though) which look bad with Quant 2. For these, I use Quant 1 with the credits function, it looks really much better. I think B-frames helps a lot for low bitrate encodes, but for high bitrate, no B-frames will look better.