Scene Changes

[Billy|B-A]

At some scene changes I get a little distrosion at the top and bottom of the scenes. I am using Gordian Knot to prepair the avs and virtual dub to encode video. I am not sure on what settings to list, so if anybody wants settings just tell me which and I will post them.

http://personal.atl.bellsouth.net/atl/p/e/perdue3/gtocap.jpg

Its at the bottom and top of some scenes.

[Koepi]

Image heigth and width must be multiples of 16, else you may run into trouble (like you impressivly showed ;P ).

Regards,
Koepi

[philippas]

I don't think that's the problem as i can see from the screenshot. Try and crop more the bottom of the picture. Many DvD's also have that problem so you have to crop a bit more than the black bars. If you used autocrop in GKnot do the croping manually and check it again.

[Koepi]

Are you reading me?

The padding code isn't always working right (still has to be investigated), so to be sure your size has to be multiples of 16.

Regards,
Koepi

[manono]

Hi-

Yeah-philippas is right-it's in the source. I've seen a bunch like that. Either crop more, or put up with it.

[zettai]

Sorry Koepi,

although you are correct that multiples of 16 are necessary for preventing distortion/problems around the edges, the screencap posted above is displaying a common source error found in medium and low-quality cell animation.

I noticed a lot of these in anime shows such as Shojo Kakumei Utena. The dirty marks would appear at the bottom of the last frames of a scene.

Obviously, it's not the kind of thing people tend to notice on TV screens so the companies tend not to care.

[Billy|B-A]

Resolution is 512x384

Heres a pic displaying both VDub windows.
http://personal.atl.bellsouth.net/atl/p/e/perdue3/pic2.jpg

I will look @ the source in vfapi codec only, will that show the problem?

[Koepi]

Hmmm, ok, 3 things:

if this is really the reason, I apologize.

2nd, I did a fresh install of my system and wanted to test if everything works ok. I captured 4 minutes of "anything", this was a series called "dragonballz" or something close to it (why do we need PISA studies in europe when they feed our kids with such stuff? it's obviously where the lack of realism and logical thinking derives from).
I noticed during compression that there are a _hell of a lot_ of interlacing issues. It looks like the TV station didn't IVTC the stuff right for PAL, there are already plenty of faded or misplaced frames in the original capture.
So I think anime can be _really really_ hard to encode.

3rd. If the two points above are true, I'm amazed that XviD copes really well with image boundaries other than multiples of 16 :) There were no (semi)official announcements that this stuff has been addressed already, so count yourself lucky if it works correctly. As some tests some weeks ago showed, boundaries at multiples of 8 can be correct, sometimes even at multiples of 4. I won't go "lower" as there you have guaranteed errors in the resulting file.

Sorry again if I was too early with my conclusions,

best regards,
Koepi

[Bulletproof]

The reason you see this distortion is because it's from an analog converted source. The people who made this DVD did not make a "real DVD". What they did was take a VHS source or LaserDisc source (Most often is LaserDisc which is analog) and transfer it straight to DVD. Real DVDs are telecined. This always happens 100% with analog material.

I should add that this doesnt happen with ALL analog material, but a very large portion of it do exhibit that problem. I have seen it many times.

[Billy|B-A]

Well I guess this answers my question.

http://personal.atl.bellsouth.net/atl/p/e/perdue3/pic3.jpg

that with vfapi reader codec only. Now looking at this mabe i should have used a different res ^_^;

[int 21h]

Originally posted by Bulletproof
The reason you see this distortion is because it's from an analog converted source. The people who made this DVD did not make a "real DVD". What they did was take a VHS source or LaserDisc source (Most often is LaserDisc which is analog) and transfer it straight to DVD. Real DVDs are telecined. This always happens 100% with analog material.

I should add that this doesnt happen with ALL analog material, but a very large portion of it do exhibit that problem. I have seen it many times.

I would beg to differ. The source of the original Mpeg-2 file is irrelevant to the authenticity of the dvd. If it follows the consortium standards for DVD, then it is DVD. The source matters little.

The reason it doesn't happen with all analog material is that some bootleggers are intelligent enough to crop up 4 pixels when capping.

[Bulletproof]

You are only being redundant, I said this happens with analog material only. "The source matters little." I think the difference between Telecined material and Capturing matters a whole lot. I have never seen Telecined material do this.

"The reason it doesn't happen with all analog material is that some bootleggers are intelligent enough to crop up 4 pixels when capping."

I have many retail DVDs that have the same problem. And the professional studios dont crop when they encouter this problem. There is software that drops 1 frame between scene changes that gets rid of it. And that's only when they're forced to use Laserdisc material or any other form of analog media. DV tapes (Which are basically MPEG-2 anyway) never have this problem either (They are just encoded to DVD specification).

[Baalthazaar]

Bulletproof is correct in this instance. The few small errors at the bottom of encoded TV Caps are apparent for all analog recorded material that I've ever done. I'm not sure for the precise reason - I think it's probably because I used RF for my inputs because I don't have cable. That said, if I use the S-Video conenctors of my Playstation 2 then I do not see the problem.

It's just impossible to get a clean capture off of an analog source using analog inputs. That's my experience, anyway.

[avih]

well, in the sat broadcast here (israel, pal), i can cap full frame, without crop, and the whole area is percicely filled with the video (even the half line at the top).

so it IS possible, i don't know how exactly do they broadcast though..

[int 21h]

Originally posted by Bulletproof
You are only being redundant, I said this happens with analog material only. "The source matters little." I think the difference between Telecined material and Capturing matters a whole lot. I have never seen Telecined material do this.

"The reason it doesn't happen with all analog material is that some bootleggers are intelligent enough to crop up 4 pixels when capping."

I have many retail DVDs that have the same problem. And the professional studios dont crop when they encouter this problem. There is software that drops 1 frame between scene changes that gets rid of it. And that's only when they're forced to use Laserdisc material or any other form of analog media. DV tapes (Which are basically MPEG-2 anyway) never have this problem either (They are just encoded to DVD specification).

No, you are being vague and ambiguous. Trying to infer that the source of an Mpeg-2 file contributes to the validity of a DVD.

Telecine, Analog Conversion, Original digital, etc. matters little as to whether something is a 'real' DVD, as to what your original post stated. You can encode SMR nAVI to Mpeg-2 that conforms to DVD standards, author the file, and you have a real DVD.

[Billy|B-A]

ummmm....just to mabe clear things up that may affect the way answer my question, this is a full retain dvd bought from Best Buy.

[zettai]

I don't think it matters that the DVD was bought from Best Buy, it just means that the source hasn't been mastered very well, so you still have the dirty scene changes. I see this a lot on anime dvds - even ones from Japan. It's just an effect of budget anime production and lazy digital mastering.

Obviously it happens much less with really modern shows as lots of modern anime are doing digital painting so you don't get these issues.

I'd just clip it, personally, as it's just noise for the encoder.

[Stabmaster-Arson]

yup, cip it and all will be well.

[Koepi]

Well, best buy was your worst buy then.

I'll close this topic now as the "xvid problem" isn't one and the original author is insulting even when i wrote an apology (which was very unnecessary - doing a beginners error with using a wrong resolution still is an error!).

.