Who can point this out: My fault or divx 5's fault?

[ChAoS Overlord]

Hi, I've done some encodes of fawlty towers with divx 5

I followed doom 9's guide, that is I used avisynth to do a fast deïnterlace & b-frames (no GMC/Q-pel though). The source is the Fawlty Towers PAL DVD, bitrate is set at 1050 for this 2 pass encode, It's been resized with Gordian Not to the resolution you can see here (512x384). Now I keep noticing some artifacts, is it my fault or DivX 5's? Could somebody with SBC (or DivX4) encodes show his version of these shots/his opinion, I don't have enough experience with either of these codecs? They have been taken from media player with standard filter settings of DivX5 (4 notches up), so I don't know the exact frame, because of not using virtualdub.

http://membres.lycos.fr/chaosoverlord/MISC%20IMG/Fawlty%201x04%2016-40.jpg
Fawlty Towers 01x04, 16:40 (Notice Sybil('s Face))

http://membres.lycos.fr/chaosoverlord/MISC%20IMG/Fawlty%201x04%2018-27.jpg
Fawlty Towers 01x04, 18:27. (Notice The Skirt)

http://membres.lycos.fr/chaosoverlord/MISC%20IMG/Fawlty%201x04%2026-43.jpg
Fawlty Towers 01x04, 26:43. (Notice The Background, Especially The Doorway)

[theReal]

I think it looks like the usual quality loss.
You can only choose higher bitrate/lower resolution/softer resizing or apply some filters to avoid these artefacts.

[ChAoS Overlord]

For resize I took neutral bicubic.

Are there better ways to deïnterlace? I don't have much experience with it, what about this decomb thing? Can anybody tell me what is the best way to deïnterlace with divx5?

[theReal]

You said your DVD is PAL - then you don't have to interlace, usually.

I think PAL DVDs are progressive, not interlaced, but I'm not sure about that. I have never deinterlaced a PAL DVD because there are absolutely no visible combing artefacts.

[ChAoS Overlord]

hmmmm when I was scrolling through the movie I saw those black lines when a person / object was moving, so I guess it was interlaced, now wasn't it? I can be mistaken of course, is that normal, those black lines?

[theReal]

When you see interlacing effects, you have to deinterlace of course.

I searched the web for facts on PAL DVDs and interlaced frames, but 99% of the sites only explain what interlaced means and they explain PAL, but none of them states clearly if PAL DVD's are progressive or interlaced (and if they do, they only assume it is so, just like I do, without any further proof or description).
I also found a site that said a very small percentage of PAL DVD's was interlaced, while most were progressive - but it seemed it was as well only a vague assumption by the author...

[Zhnujm]

thats easy ;) :
- a pal dvd from a progressive source (cinema) isnt interlaced
- a pal dvd from a interlaced source (tv) is interlaced

your pictures look like a tv-serie (?) so i think its interlaced.

of couse some time this is not true (ntsc-pal conversions,some tv-series are shot progressive...) but most time it is.

[ChAoS Overlord]

Yes it is from a (very famous) series called fawlty towers (with John Cleese).

To sum things up:

- The quality loss that I have is normal & would be comparable to what I'd get with SBC or DivX4.12?

- If the loss of quality is due to a not so good deïnterlacing method, which methods/programs are better? (I'm interested in this part anyway!)

[Teegedeck]

For deinterlacing a PAL TV source, I believe loading Decomb into AviSynth with the setting 'Telecide ()' should work just fine. Perhaps you should consider putting in a Temporal Smoother with the setting '(2,1)' after Decomb, to improve compressibility. And bilinear resizing could also improve compressibility.

BTW, I'm glad someone here compresses a DVD that is really worth it! ;)

Get on with it!

[ChAoS Overlord]

OK, I am eager to test these settings, but could you describe what decomb telecide & temporal smooth really does, so that I may know if I like the effect in advance?

[Zhnujm]

info about decomb filter:
http://sauron.mordor.net/dgraft/decomb.html

the telecide() option is only useful for reconstructing progressive frames, for real interlaced video use the fielddeinterlace() option.
but your pictures really dont look so bad. its also a 4:3 source so the resolution is higher and not so good to compress.

[ChAoS Overlord]

Are there any guides on how to set up avisynth+decomb settings? Thus far I've allways done it with gordian knot, which has a graphical interface, but as I read in the avisynth forum, it's all text based. Is there an easier way to set things up with some kind of gui when using avisynth + decomb for these tasks, because nothing has changed in the gordian knot avisynth interface...