avi to svcd...image quality??

[dekuun]

When I convert avi to SVCD with TMPGenc I sometimes have movies which have - especially in the dark scenes - a bad quality. The colours of walls and big object in the background are constantly 'moving' and change from intensity.... a bit like watercolours..
Hope you understand..cause it's difficult in English to explain..

Has this something to do with the quality of the avi or with the conversionproces..??? Can someone help out please...

b.t.w. which program is better..TMPGenc or Cinema Craft..??

[ABAB]

Could be a number of things.
Source quality.
Filters used/not used.
Quality settings such as motion search precision.
Also the type of film really, an action film will require more thought when setting your encoder up than an animated/cartoon film.

Personally I don't care much for any other encoder than TMPG (prolly cos' I've never managed to get comparable results from anything else).

Which encoder is best............Hmmmm, this could be good.

[Gazorgan]

This is typical from converting a DivX/XviD to SVCD. You need to run some filtering to clear this up. You specific problem can be easily cleaned up useing the 2D spatial filter in VDUB ( you must frameserve from VDUB to do this ). TMPGEnc has some filters you can use as well, designed for 'crawling backgrounds'

[dekuun]

Gazorgan...can you help me out a bit..where do I find this 2 D spatialfilter in Vdub..? When I go to 'video' and 'filters' and choose 'add' I cannot find him...do I have to download it?....and can you use two filters at the same time, cause I often use the subtitler too...

[ZippyP.]

In TMPGEnc you can go to the Quantize Matrix tab and select Soften Block Noise. The default is 35 but can be adjusted up or down depending on your source.

[antoniosgubba]

Hi Zippy...me again

Seems this poster is having exactly the same problem as me!

I tried using VBR and also the soften block noise option in TMPGenc but the blockiness is still there ...Dekuun, I know EXACTLY what you mean by a watercolour effect!....my svcds look brilliant in a bright scene, but in a dark scene the blacks seem to shimmer with little blocks of different shades of grey.

Also I'm pretty sure its NOT lack of bitrate thats causing the blockiness....fast action scenes do NOT show any signs of blockiness in my svcds....I'm getting more and more convinced that it is something to do with the limitations of a television set in displaying dark colours. When I play back the svcd on my PC there is no blockiness at all...it only appears when played back on my TV.

I'd be VERY interested to learn a bit more about this "2d spatial filter" and the "crawling background filter" mentioned above by Gazorgan

Gubba

[ABAB]

Trawl away boys.

http://shelob.mordor.net/dgraft/

[ZippyP.]

Gubba: The blockiness must be present from the original files if changing your encoder settings isn't helping. I don't use filters much but I know a lot of others swear by them to improve image quality. Looks like we need to do some experimenting. 8)

[antoniosgubba]

My original sources are nice quality Zippy...and as I say, my svcds play back beautifully on my PC....its just on the TV that it gets blocky...don't get me wrong though, my svcds are NICE quality in all respects except for the blockiness in very dark scenes....it certainly doesn't stop me enjoying the movie...its just that I'm a bit of a perfectionist!

As for experimenting...yes I think you're right there!...my DVD player won't play CDRWs....but I've got a 100 spindle of CDRs that I bought for the princely sum of ten quid..about 15 US$...so I don't mind wasting a few of them trying things out!

[erikur]

I am a newbee my self, but it is very logical that for me that the quality is worse on a TV, because your PC have a much higher resolution. The TV have a resolution of 512*480 or something like that

[mats.hogberg]

Strange, 'cause I get "crawling" backgrounds (dark areas mostly) on my computer screen. On the TV it's much less noticable. This is not only for my own SVCD - I'ts noticable in commercial DVDs too, even tho not that much.

it is very logical that for me that the quality is worse on a TV because your PC have a much higher resolution

My logic goes the other way: since the computer monitor is capable of more nuances and has a "crisper" picture, every flaw is much more prominent on your computer than when viewed on the telly. To boot, you very seldom sit 50 cm from your TV...

[dekuun]

I read - after a search in this forum - that the "crawling"/ "moving"colours problem can be solved or diminished in TMPGenc. with the 'noise reduction'-filter under the advanced-tab...the defaultsettings should work with most avi's...
Has somebody more experience with this..especially about the use of this kind of filter in Vdub

[Puncher]

OK guys - since i had the same problem anoying me for weeks - last week i did nothing but trying out a lot of tips which i read here or anywhere else in the web. Here are my conclusion so far of which really improved the qualitiy especially in those dark backgrounds

my equitment
virtualdub for frameserving
cce for encoding (TMPGenc would make a big diffrence)

1. Color Setting

its important to have the right colos settings during the encoding process because otherwise the colors get messed up.

either 0-255 or 16-235 - Since a TV can only show 16-235 color the final mpg should be converted to this value. but attention, there is not a general answer to this like iv'e seen it alot in "guides". It depends on your source.

If your source avi file still has 255 colors - then your encoder settings should be 16-235, in this way it will convert the color to TV-format.

If your source avi file is already converted to 16-235, the encoder setting should be 0-255, because otherwise the encoder try's to convert it again -which will mess up especially these dark colors.

To figure out how many colors your source have - you the Histogramm in the Options menu in Virtualdub

2. Use filters in virtualbud for frameserving

-Jim Casaburi's 2D Cleaner (http://shelob.mordor.net/dgraft/hosted.html)
This will make a big difference - but with wrong settings picture get's unsharp which sucks of course. What this filter does is i takes a pixel and checks its color value. then look at the surounding pixels. if these pixels color are very close to the source pixels color - the filter changes them to same color. This helps reducing this background noise and furthermore, saves bits in encoding for more difficult picture areas.

The best result's i achived with a big range (5-7 pixels) and a small treshold (2-3). A bigger treshold will make the picture very unsharp so better don't


Oke guys - this is what i figured out so far. The result i already much better-but i think can still improve a little bit

If you don't understand anything - just ask

[Puncher]

sorry guys - i ment tmpgenc would NOT make a big difference to cce

either one of this would be fine

[antoniosgubba]

Some very interesting info there Puncher...thank you!
I think you maybe onto something there...as I said above I really do think it has something to do with the TV not being able to display as many shades of grey as the PC...especially as my svcds have NO blockiness when played back on the PC.
I'll be experimenting later with what you suggested...I'll post back with the results.

[erikur]

no we don't sit that close. But anyway, the TV SET have a much lower resolution and also much lower Hertz (50) on most TV SET have, if you are not so lucky to own a 100 Hertz TV. But I am agree with you in some way, the distance that you sit compensate for the bad picture.

[mats.hogberg]

the TV SET have a much lower resolution and also much lower Hertz (50)

That's exactly what I mean. The TV is much worse than a computer monitor, masking deficiensies in the video much more than a good monitor.

/Mats

[Puncher]

hey guys - just a additional information, here i've found a good guide which explains the diffrent kind of filters and how they work, whith alot of examples:

http://nickyguides.digital-digest.com/vdub-filters2.htm

[pcboo2002]

hi puncher. read your post about the right color settings. i loaded my avi file, pressed Histogram and nothing happened. Also how do i set the color setting. i can,t find it