DVD2AVI and PAL Interlacing

[sue denim]

Hi!

This question may have been answered before but I can't seem to find it anywhere!

It's quite simple .......
I'm trying to go DVD -to- SVCD on 'The Dish'

Ripped the DVD VOBs using SmartRipper (latest version)
Created a .d2v project file with DVD2AVI v1.76

The problem comes when I try to create a .d2v file for some of the extras on the DVD.
I get a .d2v file that has classic interlacing problems - ie.jagged lines at the edge of fast moving images/objects.
Therefore, I have to de-interlace before I can encode.

This only seems to occur on the extras that were initially 'designed' for 4:3 TV ...... 'Featurette' ... 'Documentary' ... 'Interview' ... 'NASA footage' etc etc
The 'Trailer' and main movie are fine.

Why is this? ...... anybody have any ideas??

BTW - The source DVD video is Interlaced and my DVD2AVI settings are the standard for PAL (that I've used for months without a problem!)

Cheers,

Sue xxx

[stanwebber]

as you suggest yourself i imagine the footage is pure 50/60hz video. you dont need to deinterlace this material if your target format is mpeg2(dvd, svcd). nor will this material forced film or ivtc so encode straight 25/29.97fps

[sue denim]

Yeah, that's how it should be ...........

..... but when I load the .d2v files into TMPGenc or WinMediaPlayer (via AVISynth), the video looks messed up (the 'jagged' lines at the edge of fast moving objects etc).

I am going interlaced PAL DVD to interlaced PAL SVCD, but the interlacing seems to get messed up in DVD2AVI.
The only way to fix it is to de-interlace before I encode (which will re-interlace!).

Odd huh?

Sue xxx

[KoalaBear]

The only way to fix it is to de-interlace before I encode (which will re-interlace!).

Odd huh? :-?

The MPEG encoding objective should be to preserve the frame structure of the original recording: progressive --> progressive or interlaced --> interlaced, but never interlaced --> progressive or vice versa as mismatched frame modes are an invitation to trouble.

Progressive frames are coded using zigzag scanning, but interlaced frames are coded using alternate scan. The difference is very important because the motion compensation mechanism works on a different principle in an interlaced environment -- each macroblock is divided into its component fields and motion is estimated for each field separately.

When progressive frames are encoded as interlaced, it amounts to a waste of time and space because you're reserving bits for a function that the DVD player can handle by itself automatically.

When interlaced frames are encoded as progressive, inter-field artifacts (lines in the direction of motion) are locked into the picture structure and will be reproduced as-is when the decoder formats that frame for display.

Thus if you deinterlace your materials prior to encoding, code them progressive, otherwise don't deinterlace at all and code them as interlaced. Tell me which encoder you're using and I can help you find settings suitable for your needs.

[RoopeT]

This only seems to occur on the extras that were initially 'designed' for 4:3 TV ...... 'Featurette' ... 'Documentary' ... 'Interview' ... 'NASA footage' etc etc
The 'Trailer' and main movie are fine.

Why is this? ...... anybody have any ideas??

Well, here's an idea: the original material was for NTSC. When it is converted to PAL, 576-480=96 field had to be added, and this somehow messed the field order. (just guessing)

From what I have read on dooms forum, I would try to use Telecide rather than de-interlacing to fix this (haven't tried this yet myself, but will try within a few days).

[sue denim]

Back together again guys huh?!!

I hear what you're all saying but I think maybe I didn't make myself 100% clear first time out ........

DVD2AVI reports the VOB stream to be interlaced.
The VOBs playback in DVD2AVI looks fine.

When I create a project file (.d2v) and play that back, it contains the 'inter-field artifacts' you mentioned.

That's quite a reasonable theory RoopeT, but I can't see TeleCine fixing it!

What I can't understand is how come the DVD MPEG2 video looks fine and the DVD2AVI output doesn't?

BTW - I'm using TMPGenc 2.52PLUS. If I use the 'de-interlace' filter in TMPGenc, the encode looks fine (progressive of course!)

Cheers all,

Sue xxx

[stanwebber]

i dont understand either. all dvds without exception are interlaced or telecined(same difference except for pal). you should be seeing interlacing artifacts in dvd2avi preview, unless it is playing so damn fast(80fps on my system) that it escapes your eye. what fps is dvd2avi outputing? is forced film turned on by chance? are you trying to convert pure 60hz ntsc video to pal?

[sue denim]

Hi again!

OK, to answer your questions :

DVD2AVI reports the source VOB is 'interlaced'
FPS output to .d2v file is 25fps

Preview is around 80fps but that means nothing because when I load the .d2v file into WinMediaPlayer, playback is exactly at 25fps and the artifacts appear.

Forced Film is most definitely OFF (and so is IVTC!)

I am trying to convert an INTERLACED PAL DVD --to-- INTERLACED PAL SVCD.

As I stated before, it only seems to happen on certain 'disk-extras' -- never had this prob. on any other DVD (yet!)

Cheers,

Sue xxx

[duck712]

I am trying to convert an INTERLACED PAL DVD --to-- INTERLACED PAL SVCD.
As I stated before, it only seems to happen on certain 'disk-extras' -- never had this prob. on any other DVD (yet!)

I have seen this also. Some PAL-DVD's look really bad in DVD2AVI, while others look good. I read somewhere that there are actually 2 types of PAL:
- 25 FPS full frame
- 50 half frames per second --> resulting in 25fps

I hope I remember correctly. This may be the difference between your sources.