Is the bitrate high enough?

Weef · Member Joined: 13 Feb 2009 Location: Germany

This is original "source" material from a DVD.
Now I guess everybody can see those stripes. Does this mean that the bitrate is too low (vary from ~4500kbit/s - 6750kbit/s)?
PS sry I'M just noticing that I ended up in "Blu-ray/HD DVD to xyz", I actually wanted to post that on "DVD to xyz"

manono · Member Joined: 28 Aug 2003

guns1inger · Member Joined: 01 Apr 2004 Location: Miskatonic U

Converting from DVD to what ?

Are these stills from the DVD ?

Are the bands across the face visible in the footage, or only if you flick through frame at a time ?
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G)-(OST · . Joined: 01 Apr 2005

I don't see any lines either!

edit: When I tilt the screen I can.

Weef · Member Joined: 13 Feb 2009 Location: Germany

Yet, it's not about encoding at this time.
Yup, this is a still but they are still visibled when watch the DVD normally.

Are you all using TN-Panel displays o.O?

guns1inger · Member Joined: 01 Apr 2004 Location: Miskatonic U

I can see horizontal bands across the face in the top image, and some mild bands in the bow tie of the bottom image.

I would like to see a few seconds of the original footage from the top image to see what it looks like.
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disturbed1 · Member Joined: 22 Apr 2001 Location: init 4

Noahtuck · Posted: Jun 24, 2009 05:53

jagabo · Member Joined: 09 Dec 2005 Location: none

Given the bands are perfectly horizontal I suspect this is more from limitations of 24 bit color. The original animations were created on a computer using a gradient fill (in the faces) from top to bottom. When you perform that type of fill between slightly different shades you will get a little banding like that. This is because you can see the difference between two adjacent color like (R,G,B) 147,177,201 and 146,176,201 (colors taken from the top image in the provided sample).

On top of that you have the conversion of the original RGB to YUV when converting to MPEG and back to RGB for display which introduces more banding (not every color in the 24 bit RGB space resolves to a unique color in the 24 bit YUV space, and vice versa). And finally the DCT precision used in MPEG encoding can introduce even more banding.

This is why a little noise is your friend.

One of the images with a block of gradient fill using similar colors (24 bit RGB):

You can see a little banding in the gradient fill. If you examine the RGB values you'll see that the color never changes by more than one unit (in each channel) as you move from top to bottom in the filled area).

The same image converted to YV12 and back to RGB in AviSynth (as would happen when converting to MPEG and then displaying again on an RGB display):

You can see even more banding now.

Finally, here's the RGB gradient fill with a little added noise:

And the same image after converting to YV12 and back to RGB:

The banding is has pretty much disappeared in the gradient filled box (the original portion of the image is beyond repair).

Weef · Member Joined: 13 Feb 2009 Location: Germany

So if I now would say I would be willing to convert it, is there any way we could optimize the material for RGB output on a normal TFT display?

lordsmurf · Posted: Jun 24, 2009 09:48

Temporal cleaner in VirtualDub, but pull back to less than half on all of the default settings. Drop all the numbers, less than half (an 8 becomes a 3, a 10 would be a 4, etc).
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jagabo · Member Joined: 09 Dec 2005 Location: none

Weef · Member Joined: 13 Feb 2009 Location: Germany

And what would you say? Is the quality decent or would it look much better(sharper) when the "source" would supply the max 10.000kbit/s?
There is the option that I could use another source...

jagabo · Member Joined: 09 Dec 2005 Location: none

In the second image gradient I posted there was no MPEG compression. There was simply a conversion from RGB to YV12 and back to RGB. There is almost as much banding as in your DVD sample. So MPEG compression isn't contributing much to the banding, it's the colorspace conversion. Encoding at a higher bitrate will not make much difference in the banding.

If you can get hold of the original RGB source you could add a little noise and eliminate the banding problem.

Weef · Member Joined: 13 Feb 2009 Location: Germany

No no no, my last question was about the outlines and the patterns involved, if those would be sharper with a original source of a higher bitrate!?

jagabo · Member Joined: 09 Dec 2005 Location: none

Weef · Member Joined: 13 Feb 2009 Location: Germany

Seems to be like every one of my video players handles it on that way o.o ....
I dunno what makes it show it in 852x480

jagabo · Member Joined: 09 Dec 2005 Location: none

The DVD frame size is 720x480 but the display aspect ratio is 16:9. So media players stretch it to 853x480. This is fine for viewing but not for analyzing fine details of the video. You should use an editor like VirtualDubMod to open a VOB file, then save a frame as PNG via Video -> Snapshot Source Frame.

Weef · Member Joined: 13 Feb 2009 Location: Germany

Sure, how could I forget this >.>...perhaps I just naively thought they would treat it better due to it's unique pattern properties.
But here it is

jagabo · Member Joined: 09 Dec 2005 Location: none

I doubt you'll find any source significantly better than that unless there's a Blu-ray version.

poisondeathray · Member Joined: 07 Sep 2007 Location: Canada

This type banding commonly occurs in anime when grain remains before heavy denoisers are used. Not a good quality source.

You can try GradFun2DB() or one of it's derivatives (e.g. GradFun2DBMod). It's commonly used for anime banding. You can tweak the parameters, but definite improvement in this banding even at default settings. Read the included documentation for more info

ImageSource("sassi.png")
ConvertToYV12()
GradFun2DB()

Weef · Member Joined: 13 Feb 2009 Location: Germany

I'm excited poisondeathray^^
Even the effect is little, it makes the picture look far more appealing.
Since you seem to know the one thing or two when it comes to animes, I have a question or you.
Is it advisable to purchase Anime DVDs with only 2 episodes for a better base quality? I would know a way to get the original japanese DVDs.

lordsmurf · Posted: Jun 25, 2009 10:26

My television has built-in filters, I'd never even notice this noise watching the DVD.
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poisondeathray · Member Joined: 07 Sep 2007 Location: Canada