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Old 31st January 2006, 03:47   #1  |  Link
Episodio1
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Why most PAL DVD's are interlaced?

What is the budget to make 1000 progressive DVD compared to 1000 interlaced?

I thought they scan all frames and then encode them into MPEG-2. So the cost between interlaced and progressive is... none? Only software dependant?

Could someone post pics of the machinery used to make a DVD transfer?

Thanks.

Last edited by Episodio1; 31st January 2006 at 22:14.
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Old 31st January 2006, 03:54   #2  |  Link
Matthew
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If you are talking about movies then they are not usually interlaced, as they are typically shot on film. tv series are more likely to be shot on video, which is interlaced.

However in my experience it is very common for PAL movie DVDs to be flagged as interlaced even though they are actually progressive.

Are you relying on your eyes (combing) or flags in making this assessment?
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Old 31st January 2006, 15:28   #3  |  Link
Episodio1
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Oh! I didnt know about that flags in PAL DVDs. Yeah, I was talking about them (I dont have access to ntsc dvd's).

So whats the diference in manufacturing pal dvd with the interlace flag and progressive?

Apart from speeding up the film from 24 to 25fps is there any other way to create a PAL dvd from film?
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Old 31st January 2006, 23:09   #4  |  Link
Matthew
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It's just settings in the encoding system, I have no idea why it's so common. In terms of backing up, according to the CCE FAQ, progressive material flaged as interlaced should be encoded using ConvertToYUY2(interlaced=true) in avisynth (assuming you are re-encoding), but other than that may be treated as progressive.

In terms of other methods, it is possible to create truely interlaced PAL when going from 24 to 25 by repeating fields e.g.

AVISource("C\test.avi",audio=false)
ConvertToYUY2()
ChangeFPS(50, 1)
SeparateFields()
SelectEvery(4, 0, 3)
Weave()

One can also use DGPulldown to achieve this using flags, which is more space efficient and it's possible to return the video to its original form by stripping flags.

But these methods result in video that is a tad jerky.
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Old 1st February 2006, 00:50   #5  |  Link
Episodio1
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Thank you, Matthew. ^_^
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Old 1st February 2006, 05:06   #6  |  Link
manono
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And the third way is to use an NTSC master for the PAL DVD and blend the hell out of it.
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Old 15th February 2006, 10:55   #7  |  Link
auenf
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blending is bad

the progressive flag is pretty much only used for pulldown in NTSC, in the PAL world when playing on a normal tv (which is the primary setup for DVD) the progressive flag gets ignored and the dvdplayer and the tv happily show you you the movie as if it was interlaced (ie, field followed by field followed by field, etc etc) and noone notices that theres a 50% lack of motion compared with a real interlaced file cause it IS about 4% smoother than it was in the cinema at 24fps

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Old 15th February 2006, 11:53   #8  |  Link
frank
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There is a big misunderstanding.
Important is the encoding mode, not only the source!
You can:

1) Encode interlaced material (live video) as interlaced.
Necessary.

2) Encode progressive material (movies) as interlaced.
This is not necessary, but the producer has the advantage of no need to care about the content of the whole dvd.
Some extras may be interlaced. Menus are often interlaced. And so they encode the whole movie as interlaced when the bitrate is high enough.

There is a difference in color space between interlaced and progressive encoded frames (4:2:0).
For right colors you have to decode interlaced encodings as interlaced even in the case of progressive frames!

If you don't trust the flags, then it's very hard to see in what mode a progressive movie is encoded.

Last edited by frank; 15th February 2006 at 12:01.
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Old 15th February 2006, 13:54   #9  |  Link
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What happens when you are using the progressive output from a DVD player? If the disk contains film (progressive) material which has been encoded as interlaced, then the player can only assume that the material is interlaced and therefore deinterlace the "fields" to produce a progressive frame for output. If the disk had been encoded as progressive then the player would presumably just output the progressive frames as-is.

The question is, is there likely to be any picture quality loss in the former case where the material is needlessly passed through a deinterlacing process? If there IS a slight loss (and I don't know if this is the case) then it may be better for film material to be encoded as progressive rather than interlaced.

Any thoughts?
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Old 15th February 2006, 14:50   #10  |  Link
manono
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Hi-

Quote:
blending is bad
Hehe, tell me about it. But that doesn't mean it isn't done all the time. It may be a bigger problem for NTSC people than for PAL people though. I see the damn things way too often (PAL masters used for the NTSC DVD).

Quote:
The question is, is there likely to be any picture quality loss in the former case where the material is needlessly passed through a deinterlacing process?
Of course there will be a quality loss. How much depends on the quality of the deinterlacer. Are you talking about for PAL, NTSC, or both? My experience is with NTSC mostly, and when you have hard telecine (already telecined film encoded as 29.97fps interlaced), a flag reading DVD player can only deinterlace it for output to a progressive display. Just try and watch the mess that a software player such as PowerDVD produces with such material. If you have a better cadence reading player, it can spot the 3:2 cadence and "IVTC" it on-the-fly, so-to-speak. I'm not real sure how PAL DVD players handle it, but since almost all of their movies on DVD are encoded as interlaced, even if the source is progressive, I have a feeling that any player with decent 2:2 pulldown detection will output it to a progressive display without unnecessarily deinterlacing it. But I'll defer to my PAL bretheren on this.
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Old 24th October 2006, 18:30   #11  |  Link
Jeff D
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Diggin' up this old thread to get some information.

I've got a PAL DVD that I'm trying to convert to NTSC. This is my first experience with PAL (25fps) DVD so I'm in the learning mode.

It's a film source so I figured it's 24fps source and was thinking if I use DG's pulldown and then some ifo tweaks I should be able to get it to playback fine.

Process was demux VOB (vobedit), pulldown fix (DGpulldown) and then recreate DVD VOBs (ifoedit), fix ifo's for NTSC (ifoedit).

And everything was working until I tried to do a shrink after everything else. DVDShrink, Rejig and other appear to choke at this point.

I started over demux VOB (vob edit) and recreate DVD set (ifo edit) then tried to shrink that and things worked fine. So I started looking at dgpulldown as a possible cause of the problem. That's where I discovered that the source doesn't have progressive flag set in the GOPs. From this thread it appears this isn't an issue.

I'm looking to find out if there's a way to confirm that the source is progressive (a requirement of dgpulldown) and not just misflagged.

EDIT: BTW, If I reverse the order of my process to shrink first things work and the film part looks great. The reason I wanted the shrink to happen second was a attempt to keep the chapter points correct. There may be another way, but I don't know about that. I'm just really looking to figure out how to confirm progressive frames. And I really think I have done that, but looking for confirmation.

Last edited by Jeff D; 24th October 2006 at 18:36.
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Old 25th October 2006, 00:04   #12  |  Link
manono
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Hi-

If you really intend to convert from PAL to NTSC, you'll have to resize from PAL 720x576 to NTSC 720x480. This will mean reencoding.

To determine if it's interlaced or progressive, look at the frames. If it's a movie, the chances are very good (but by no means 100%) that it's progressive. If you don't see interlacing, it's not interlaced.

The chapter points will have to be adjusted for NTSC. No big deal.

If you intend to do it right, don't bother trying the quick fixes, like patching the IFOs.

Last edited by manono; 25th October 2006 at 00:06.
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Old 21st November 2006, 11:10   #13  |  Link
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if the PAL dvd is progressive, just resize and 'assumefps' then encode with pulldown enabled.

you'll have to resize the audio by 4% to match.

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Old 12th June 2020, 13:04   #14  |  Link
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Hi guys!
What's Doom9's policy about ~1½ decade old thread necromancy?

Nah, well, on a more serious note, I found this thread (Google) since I'm driving myself nuts over a small first world:ish problem that has come up.

I have this old PAL DVD that I thoughts I'd make a hard drive backup of. I usually keep it untouched (no re:enc) by a simple...

Code:
mkvmerge.exe -o dvdbackup.mkv VTS_05_1.VOB
...which is automatically concatenating all .VOB files in the sequence, putting the right aspect ratio flag (16:9 or 4:3, depending on source) and muxing all audio and subtitle tracks.

However, this movie is showing up as interlaced (TFF) but I have investigated the M2V stream thoroughly and not a single frame is in any way interlaced, it's strictly progressive.

So, I'm guessing most software players that catches this interlacing flag (and then puts on some automatic de-interlacing thing in it's filter chain) will still give me a pretty descent playback. I would probably not be able to tell the difference at all from if there was no interlace flag.

However, I'm a neurotic person and it has become like a nail in my eye. I want things to be as supposed to be. So, I have run the entire movie through Restream where I have changed the value under "Picture Coding Extension" from TFF to Progressive and also flagged "Progressive" under Sequence Extension.

Then I remux:ed the entire thing. It still plays nice (can't tell the difference) and Mediainfo is now listing it as progressive.

So, my question is, can this have any bad side effect that I have not become aware of? Something that would make me rather want to keep things as they were instead of messing around with it?

Cheers!
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Old 15th June 2020, 05:08   #15  |  Link
manolito
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Most commercial PAL DVDs are flagged as interlaced (even if the content is 100% progressive) because the guys at the mastering house are either just lazy or incompetent...
OTOH encoding progressive content as interlaced does hardly cause any damage, so you can get away with it. The other way around (encoding interlaced content as progressive) would destroy your encode badly.

Progressive PAL DVDs are absolutely legal, and for progressive content they should be encoded and flagged as progressive.

Have a look at this older thread:
https://forum.doom9.org/showthread.p...73#post1745173

There are two correct ways to flag a progressive PAL video stream:
1. Check "Frametype Progressive" AND "Progressive Sequence", but DO NOT check "TFF". All libavcodec based MPEG2 encoders do it this way.
Quote:
Strictly speaking, the MPEG2 spec allows TFF=1 with progressive_sequence=1 but it then signals frame pulldown (in conjunction with RFF=1).
The TFF flag has a different meaning when "Progressive Sequence" is checked, so you must not check TFF together with Progressive Sequence.

2. The other option is to check "Progressive Frametype" AND TFF, but DO NOT check "Progressive Sequence". This how CCE does it.


Cheers
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