losing detail movie, or is it too detailed?

[Kilcher]

Hi everyone, I have tried looking at the forum for my specific concern, but didn't really find a thread that was fitting. Here is my problem.

I finished ripping "A Knight's Tale" (132 minutes NTSC) with divx 4.12 using gordian knight.

Here are my settings:

Video: 592 x 240 using .392 bits/pixel and a compress of 54%.
I don't have the log with me (I trashed it), but my bitrate came out too approximately 1300-1330 for a 2 cd rip.

I also used sharp bicubic with no other filters.

When I played it, I wasn't happy with the quality at all. Overall, the movie was not sharp at all. I can even see lots of really really tiny blocks (macroblocks?). My question is this...

This is a quote from another thread:
====================================================================
To those who encode their movies ALWAYS @ 640x or higher:
You don't get over 60% in Gknot compressability check, do you? That means the quality of your movie will be inferior.
On the other hand, when I encode at 512xsomething and get over 60% I have lost some details, right?

It's kind of a double mill, isn't it?
1) Keep more details and have lower quality
2) Lose some details and have higher quality
=====================================================================

From the above quote, I'm not quite sure if my lack of quality is from too much detail and thus lower quality, or lose detail and have higher quality. This all seems so conter-intuitive.

On another note, is the blurriness and really tiny macroblocks due to #1 or #2?

In my case, would you have increased the resolution (thus decreasing bits/pixel and compressibility), or increased the resolution (thus increasing bits/pixel and compressibility).

I'm so confused!:confused:

[jonny]

This movie is hard to compress...
I think you should move to DivX5 with B-Frames (compressibility test with DivX5&B-Frames is ~54% at 704x304 (2CD & audio at 128))

[theReal]

You shouldn't use sharp bicubic resizing. In your case, I'd use soft bicubic or neutral bicubic at most. You might also want to try filtering. Some say temporalsmoother BEFORE resizing helps a lot without losing detail - but it's slow as hell. I think Gordianknot applies the filter after resizing. Try it when nothing else helps!

The question always is: the quality looks not good at 512x..., when I apply a little noise filter, I could raise the resolution to 64x... but does it look better? Only answer: try it!

Your question about decreasing/increasing resolution: When the quality is bad, always decrease the resolution until you reach 512x...
Below that is not good, I think, but I rather have 512x... than any higher resolution when the quality is not good enough (blocks etc.)
Then, as a last resort, consider filtering (and maybe increasing the resolution again)

[Acaila]

You get only 54% for a 2-CD movie? Man, that's low!

Anyways, 512 is definately too low for 2 CD's, go for 640 instead. Even a 3-hour movie looks excellent at 640 if you put it on 2 CD's. I'd also recommend neutral bicubic resizing and TemporalSmoother(1) as filter.
Also be sure to encode the credits at a very low % to save bits for the main movie.

Did you encode your audio, and if so to what bitrate?

[Kilcher]

Thanks all for your comments.

512 is definately too low for 2 CD's, go for 640 instead. Even a 3-hour movie looks excellent at 640 if you put it on 2 CD's. I'd also recommend neutral bicubic resizing and TemporalSmoother(1) as filter.
Also be sure to encode the credits at a very low % to save bits for the main movie.

Did you encode your audio, and if so to what bitrate?

If I go to 640, it will be .320 with compress of 44.3. I'm totally confused here. Wouldn't increasing the resolution make the quality of the movie even worse?

You said something about not going below 512.. is this because you lose too much detail? On the other hand, if there wasn't a lot of bits per pixel in the first place and if the compress was still pretty low, would decreasing below 512 still be that bad? I guess the alternative is to go to 3 cds, but I want to avoid that at all costs.

I guess this movie is just highly uncompressible.

I'm doing another dvd rip right now of "Don't say a word." I'm going to use this movie to test all the different resolutions and see what's best.

This movie has given me a headache as well. When i did a compress check at 672x 272, it gave me .361 bits with a compress of 120%!!!! Resizing it to an insane size of 800x336 yields a still high compress of 81.5% What does this mean? Does this just mean that this movie is highly compressible, thus I can choose whatever size I wanted and it would still look good? Do I still have to worry about bits/pixel in this instance?

Thanks a lot guys!

[Kilcher]

Thanks thereal for your comments.

You shouldn't use sharp bicubic resizing. In your case, I'd use soft bicubic or neutral bicubic at most. You might also want to try filtering. Some say temporalsmoother BEFORE resizing helps a lot without losing detail - but it's slow as hell. I think Gordianknot applies the filter after resizing. Try it when nothing else helps!

Isn't sharp bicubic best for the sharpest images? Since my movies always seem so blurry and fuzzy, i thought this would be the best setting. Am I right to say as the more you move away from sharp, (eg to neutral and bilinear), it gets more and more fuzzy, because it's trying to attempt to smooth out all the blocks?

Also, most of my movies have really tiny macroblocks. They're really really small, almost like the effect when you zoom in on a jpg and it becomes pixelated. I don't know these are macroblocks, but just to make sure that I'm getting this... these blocks are here because the lack of detail of the movie and not too much detail right?

If I apply noise filter, the pixelation will go away, but in doing so, wouldn't the image become even MORE blurry and unsharp. I wish I had the vobs to this movie. I will try these different filters on "don't say a word." I always thought to use these filters and such only when you don't have a high bitrate (ie 1 cd rips), but since I'm doing it on 2 cds, I thought I wouldn't need it. I guess I was wrong


Thanks again thereal

[Kilcher]

Oops, I forgot.. I encoded the audio at 128.

[theReal]

"Wouldn't increasing the resolution make the quality of the movie even worse?"
Yes, but when you're using soft bicubic resizing and maybe some filtering, you should be able to increase the resolution.

"You said something about not going below 512.. is this because you lose too much detail?"
This is just my personal experience/opinion - below 512 seems to lose a lot of detail while 512 is still ok.

"Don't say a word" seems to be the other extreme. Best use a resolution of 704x... (it's not recommended to increase the size above 100% of the original), use sharp bicubic resize and be glad if the compressibility is below 100%. If it's above 100%, add some specials, increase the audio bitrate, whatever.

You never have to worry about the bits/pixel - as you can see this value doesn't mean too much. The compressibility check is what counts!

[theReal]

I wish I had the vobs to this movie.Ooops. That means you only have the divx? Then leave it as it is! Reencoding divx will always result in bad quality.

Soft Bicubic resize and noise filters make your movie a little blurrier, but not as much as lowering the resolution. Especially soft bicubic resize looks very good in my opinion, I always use it when I can't get above 60%

To try the filters on your extremely compressible movie wouldn't be a good idea though. You're already struggeling to get it big enough and you would make it even more compressible with filters.

[Kilcher]

I would like to try the different temporalsmoother settings but I have a few questions. How do you know if you did the smoother before or after the resize?

Do you press "save and encode" and then open the avs file and change the temporal smooth settings? Would this be temporal smoothing before or after resizing?

I think I've gotten to the point where nothing makes sense now. I think I've had too much input to my brain in too little time!:eek:

Another question... (sorry thereal or whomever answers my annoying questions)

What's the difference between doing it before and after?

[Acaila]

I would like to try the different temporalsmoother settings but I have a few questions. How do you know if you did the smoother before or after the resize?

Do you press "save and encode" and then open the avs file and change the temporal smooth settings? Would this be temporal smoothing before or after resizing?

There's a checkbox in GKnot's avisynth window that says "Put noise filter before resizing (slower)". Check that and the TemporalSmoother will be used before resizing.

[jonny]

Now i've finished knight's tale at 704x304 (2 - 90min CD) audio at 128, neutral bicubic + little noise filter + biframes with DivX 5, comp test is 61.6%, final Avg quantizer: 3.934464, it looks good, i think better if i don't use noise filter (without noise filter compress go to 57%)... hope this help :)

[Kilcher]

I'm glad your movie turned out so great :) This is a really stupid question, but the compress check for each of the resize will be different right (e.g. sharp vs. neutral) will have different compressibilities?

Do you get the little tiny blocks (really small) when you make the movie full screen?

kilcher

[theReal]

Do you get the little tiny blocks (really small) when you make the movie full screen? I was just wondering if maybe your problem has nothing to do with bitrate and quality, but with hardware overlay capabilities of your graphics card (drivers).
Some cards can only display correct fullscreen video that has a Hx32 Wx16 (or Hx16, Wx16) resolution. I had a Geforce 2MX that was one of these cards, so I know what I'm speaking of...

[Kilcher]

You know, I never thought about that! I have a pretty crappy NVIDIA TNT2 64 video card. I wonder if that's the problem. Can you explain this overlay thing to me again and what I should do to correct this? I guess try different 16, 32 settings? What type of problems were you experiencing when you had your geforce card? Did you have that pixelation effect when you were viewing movies full screen?

A lot of the movies I've dled doesn't have this pixelation problem when viewing full screen. Could this be because they encoded it at the "correct" 32x, 16x settings?

I've been using Hx16 Wx16 on all my rips. I wonder if that's the problem. I'm going to rip "10 things I hate about you" tonight and have some screenshots of these annoying macroblocks I've been talking about.

You never have to worry about the bits/pixel - as you can see this value doesn't mean too much. The compressibility check is what counts!

Doesn't the bits/pixel tell you how much detail is going into the frame? Isn't that important? I've been to forums (digital digest) where people say that they only care about the bits/pixel and not the compress. Your view seems to be on the other end of the spectrum.

Now I'm really confused.:confused:

[jonny]

>I'm glad your movie turned out so great This is a really stupid question, but the compress check for each of the resize will be different right (e.g. sharp vs. neutral) will have different compressibilities?

Yes between sharp-neutral there is a difference of about 3%-4% (i don't remember the exact value)

>Do you get the little tiny blocks (really small) when you make the movie full screen?

No little block... try w-modul=32 h-modul=16 or try to play it with DivXG400 (i think is present in the download section)

[theReal]

When your movie looks ok when viewed at 100% size, but any size bigger than that, including fullscreen, gives you a really blocky picture and kind of slow playback, it's the graphics adapters fault.

I can't imagine anyone would only care about the bits/pixel value and neglect the compressibility value. I mean the bits/pixel doesn't tell you anything about that one movie you're dealing with, it only tells you how many bits per pixel can be used at a certain bitrate at a certain resolution. With some DV homevideo sources, you need at least 0.450 to make it look any good (compression value of ~ 55%), while a compressible DVD will reach a compression value of 65% at only 0.20 bits/pixel.
b/p is a first indication of what you should try first for resolution and bitrate, but as soon as you have done a compressibility check, forget about it.