More sharpness?

[Subster]

Hi there!

Well, I always compress my DVDs with the following settings:

- DivX
- AC3
- 2 CDs (very long movies 3 CDs)
- Minimum width 640 (AGK often chooses 672 for the final AVI)

I know that details get lost during compression, but is it possible to get a little bit more sharpness? Is there a hidden switch somewhere which activates e.g. the sharpen filter in VirtulDub?

And what about the resolution? I watched some AVIs with resolutions like 704x??? or 720x??? and they appear somehow sharper than my own AVIs.

I don't know much about all this compression stuff and I appreciate every hint you can give me. :)

[manono]

Hello, and welcome to the forum-

You can't (yet) add your own filters to AutoGK. You'll have to do such things through Gordian Knot, or on your own. The closer to the original DVD resolution, the sharper the resulting AVI. That might explain why the 704*xxx or 720*xxx AVIs you've seen might look sharper than your 640*xxx or 672*xxx videos produced by AutoGK. In addition, if the compress test results aren't high enough, AutoGK will switch to a softer matrix. There is a hidden switch to force it to use the sharper matrix.

[Subster]

Oh ok.. I always thought that it's better to let AGK decide which resolution is best, dependent on the the quality of the source. In one case, AGK has chosen 512*384 (Auto mode) for a 4:3 DVD. That's why I'm a little bit unsure.

So when I compress a DVD with AC3 (2 CDs), may I choose a high resolution with forced sharp matrix without any problems concerning the quality?

[niamh]

You use DivX.The DivX codec is naturally soft looking too. You could have a trial with XviD,which is generally sharper, and decide for yourself :)

[Subster]

OK, I'll give it a try!

Thx so far. :)

[manono]

Good eyes, niamh. I missed that he was using DivX, although it's there, plain as day. That matrix stuff I mentioned was for XviD. The chances are good, Subster, that the sharper AVIs you've seen are XviDs. You can open them up in GSpot to confirm.

So when I compress a DVD with AC3 (2 CDs), may I choose a high resolution with forced sharp matrix without any problems concerning the quality?

You can certainly force any resolution you want, and the sharper matrix (with XviD), but there is no guarantee for the resulting quality. Keep an eye on the compress test percentage. For example, that one that wound up at 512x384; had you forced 640x480 from it, the chances are good that it would have looked like garbage. The kinds of things you're looking for if the quality isn't so good would be loss of detail, mosquito noise around hard edges, moving or wavy backgrounds, and blockiness during action scenes.

[Spyn]

use gordian knot and choose the resize method "lanczos resize" to get more sharp result.

and I advise you to use the xvid codec, i think it is better than divx.

[len0x]

Originally posted by Spyn
use gordian knot and choose the resize method "lanczos resize" to get more sharp result.


What do you think AutoGK's using ?..

[Spyn]

Originally posted by len0x
What do you think AutoGK's using ?..

there isn't an algorithm to choose the resize method according to the compressibility test ? I thought...

Subster, you can also use sharp avisynth filter like MSharpen but it reduce compressibility, try xvid first.

[len0x]

Originally posted by Spyn
there isn't an algorithm to choose the resize method according to the compressibility test ? I thought...


If with lanczos resize is not possible to get good looking video then by forcing usage of it you'll only make video look worse (same goes for any other sharpening method)

[Spyn]

Originally posted by len0x
If with lanczos resize is not possible to get good looking video then by forcing usage of it you'll only make video look worse (same goes for any other sharpening method)

if the compressibility test give a 80% value with bilinear resize, it will give about 70-75 % with lanczos resize, in this case, use lanczozs resize will give a more sharp video and i don't think the quality will be worse, no ?

[len0x]

Well, you obviously don't know how AutoGK works - coz it uses Lanczos for comp test already, so your advice of using GK and lanczos makes no sense to me...

@Subster
XviD is sharper because its able to use MPEG quantization matrixes while DivX's only using H263 quantization type.

[Spyn]

to get a result more sharp i think GK is better than AGK cause of this multiple options, lanczos resize is one of them and i don't understand why you said it has no sense if AGK use bilinear in some cases...

and GK lets choose the resolution to get more details by choosing a high res.

[len0x]

Originally posted by Spyn
AGK use bilinear in some cases...


No it doesn't. How can you compare two tools directly if you don't know how one of them work at all?

Originally posted by Spyn
and GK lets choose the resolution to get more details by choosing a high res.

There is a reason for not choosing higher resolution, otherwise everyone would be encoding at 720*xxx, don't you think?

[niamh]

and GK lets choose the resolution to get more details by choosing a high res.
you can only get more details if you have enough bits/pixels to play with in the first place.
AGK chooses the highest resolution available for a decent result, len0x has fine-tuned it long enough to know what he's doing.

by bilinear, you mean bicubic, right? cause if you genuinely think bilinear resize gives a nice result, you must have terminal blindness :p

[Spyn]

hum, bilinear don't give a worst result than bicubic or lanczos, they are just different, bilinear blur the images to make them more compressible.

In one case, AGK has chosen 512*384 (Auto mode) for a 4:3 DVD. That's why I'm a little bit unsure.

i don't think this is the best choice to reduce the res and still using lanczos...

[unskinnyboy]

In my experience, 512x384 is indeed the best resolution for most FS movies. What else do you think could be an ideal one?

P.S: Again, there are cases where you can afford to have 640x480, but depends on a lot of factors.

[fewtch]

Other factors count too. For example, some people (like myself) prefer to watch movies on PC monitor in full screen despite the drop in perceived quality. IME, the quality loss is substantially less if resizing is done in encoding step rather than at playback time -- so I go for larger than usual resolutions, usually minimum 640 horizontally no matter what AutoGK thinks. This results in an *increased* fullscreen sharpness and quality, because less resizing needs to be done by the player app (none, if I use 640x480x32 fullscreen resolution).

[len0x]

Its all depends on the player as well. WMP, for instance, does horrible resizing.

[HairDude]

Which player would you suggest? I use both MPlayer and WMP.

[len0x]

Never used MPlayer, but mostly BSPlayer. Some software DVD players (like PowerDVD) do pretty nice job as well.

[HairDude]

I'd probably use BSPlayer as my main player, if it didn't force me to use a skin. Never really been into skins myself.

-
HairDude

[neo_anderson]

Originally posted by len0x

@Subster
XviD is sharper because its able to use MPEG quantization matrixes while DivX's only using H263 quantization type.

Hey, even divx fusion has MPEG quantization along with h.263 and h.263 optimized, but the official divx guide recommends to use h.263 , not mpeg, why?

[len0x]

because mpeg quant is not implemented correctly in DivX and give inferior quality comparing to h263...

[fewtch]

Originally posted by len0x
Never used MPlayer, but mostly BSPlayer. Some software DVD players (like PowerDVD) do pretty nice job as well.
Yeah, I agree... BSPlayer has (among) the best resizing I've seen. Originally posted by HairDude
I'd probably use BSPlayer as my main player, if it didn't force me to use a skin. Never really been into skins myself.
Me too... also, BSPlayer has a kind of flaky/buggy feel to it. Things don't always work as they should. I tend to use Media Player Classic more often (via Send To). Still have WMP set as default file association, for test purposes mostly. One thing about WMP is it barfs quickly if something's wrong.

[HairDude]

MPC is quite good. There was a reason why I don't use it at my default player, but I can't remember what it is. :)

I've reinstalled BSPlayer, just to see if I can put up with using a skin. I wouldn't say it feels buggy to me, though.

It's a shame there isn't a decent GUI for MPlayer/MPlayer Win32.