Progressive or interlaced DVD

[pityu]

Franklin2K and Gerti67 had a talk about that topic.
I do not understand what should we see on DVD2AVI when a DVD film is interlaced? Horizontal lines? In every 2nd row or just some lines on one frame?
10 PAL films were tried and only one of them was stated progressive by DVD2AVI and I have not seen any lines. BitrateViewer told me the films were interlaced too.
Thanks.

[Labersack]

Look for a scene where something (a Car, a person...) is moving fast from left to right (or the other way of course). If the whole movie and not only parts is interlaced, you can see the combing effects quity clearly. If you see them, there will be no doubt, they are quite obvious.

[UltimateDBZ]

You could also take a directdraw overlay supporting screencapture application and take a screencap of the movie at any random frame, then open it up in your favorite image editing application and zoom in nice and far to take a look. Or, if you have WindowsXP (dunno if other versions have it) you could use the included zooming utility in the Accessibility subfolder of your start menu. Either method should clearly show separated lines if the source is interlaced.

[pityu]

Great. I will try with XP.
Thanks.

[Moondust]

I am having kinda of the same problem as the topicstarter. I thought bitrateviewer would always tell me flawlessy if I have a progressive or interlaced DVD at hand. Now bitrateviewer told me something weird when I tried to figure out what type it was.

Scan type: ZigZag
Frame type: Interlaced

I thought that only progressive material had zigzag scanning and interlaced DVDs had alternate scanning. Bitrateviewer tells me this interlaced DVD has zigzag scanning (?). Is this a flaw or is this combination possible? Should I check zigzag scanning in my Interlaced CCE template with these kinds of DVDs?

I hope someone can help me out and preferably explain how this works for my better understanding. Thnx in advance!

[Sulik]

Bitrate Viewer is messed up: the progressive/interlaced frame and zig-zag/alternate scan type are per-picture settings. The bitrate viewer only displays the settings of the first frame, even though it may very well change throughout the sequence.

[Moondust]

Originally posted by Sulik
Bitrate Viewer is messed up: the progressive/interlaced frame and zig-zag/alternate scan type are per-picture settings. The bitrate viewer only displays the settings of the first frame, even though it may very well change throughout the sequence.
I believed a DVD was or interlaced or progressive. If I understand you correctly it differs throughout the movie.

What is the best way to handle the interlaced/progressive dilemma when encoding DVD2DVDR?

[Matthew]

PAL movies are frequently marked as interlaced throughout the video stream even though they are 100 percent progressive.

It's just a flag, so encode as progressive/zigzag unless you see combing.

[Moondust]

But can it be said that zigzag scanning always goes with progressive frames and alternate scanning always goes with interlaced frames?

[Moondust]

Originally posted by Matthew
PAL movies are frequently marked as interlaced throughout the video stream even though they are 100 percent progressive.

It's just a flag, so encode as progressive/zigzag unless you see combing.
What would be the best way to test for combing to see if it's interlaced or not? For example the movie Amelie, there aren't any fast scenes in that movie. I have to see if its interlaced or not another way. But how?

[Moondust]

I encoded an interlaced (alternate scanning) movie with interlaced settings (alternate scanning and no deinterlacing) and progressive settings (zigzag scanning and telecide), but looking over the results time after time, I can't see any difference in quality. And I mean, I am really looking very very hard to see any differences.

Is it just this movie, or can the result be clearly visible when watching both the interlaced encode and the progressive?

[Matthew]

Yeah zigzag goes with progressive and alternate goes with interlaced - follow those rules when you encode regardless of what bitrate view says (e.g. if it says progressive/alternate, still use progressive/zigzag in CCE).

There is always movement in a movie - a person walking across the screen is enough. I just use DVD2AVI and advance a few frames. If there is combing, you'll notice it.

[Moondust]

Well, I have been trying for quite a while now to actually see combing, but now I wonder if I even know exactly what combing is. My present definition of combing is that in movement you see that the lines are not horizontally in the right place to make the right picture.

When using DVD2AVI, what exactly should I do to see combing? Preview and pause in a scene with a lot of movement?

[Matthew]

In DVD2AVI just pick a frame at random, examine it and use the skip forward button (or whatever it's called) and examine a few more frames.

Look at arms, hands, heads etc and you should see horizontal lines around these "edges" that are definately not going to be there when you watch the DVD on a tv. I'm telling you, you cannot miss it if you look at just 5 frames, say.

Unless the DVD is of a tv series, it's EXTREMELY unlikely to be interlaced. I wouldn't be surprised if you've never had a movie DVD that was interlaced.

[Moondust]

Originally posted by Matthew
In DVD2AVI just pick a frame at random, examine it and use the skip forward button (or whatever it's called) and examine a few more frames.

Look at arms, hands, heads etc and you should see horizontal lines around these "edges" that are definately not going to be there when you watch the DVD on a tv. I'm telling you, you cannot miss it if you look at just 5 frames, say.

Unless the DVD is of a tv series, it's EXTREMELY unlikely to be interlaced. I wouldn't be surprised if you've never had a movie DVD that was interlaced.

Thnx for your reply, I really appreciate this. Really want to get this clear.

I am living in Europe. That means I only see PAL R2 DVDs. Bitrateviewer and DVD2AVI told me most DVDs were interlaced. So your answer really surprised me. Looking closely at some pauses in several movies, I tried looking for artifacts like in this example (http://www.fuego.de/Writing/fachstorys/images/videodruckimages/Bild_05_de-interlaced.jpg) here, but didn't find any. Fast movements are only kinda blurry, that's all. Are these movies I am dealing with progressive material despite all software saying to me its interlaced???

I have just done a backup of material that DVD2AVI and bitrateviewer say its interlaced done with interlaced settings and one with progressive settings. I have to be honest to say that I dont see any difference in quality when watching it very closely on my pc monitor. Do you know what usually happens when you encode progressive material with interlaced settings and vice versa?

[Matthew]

Originally posted by Moondust
Are these movies I am dealing with progressive material despite all software saying to me its interlaced???

Yup. I'm in region 4 (au) and I find well over half of progressive DVDs are marked as interlaced. In the case of PAL progressive material, I've come to the conclusion it's just a meaningless flag.

The simple fact is that any movie with a decent budget is shot on film at 24 frames per second. This is progressive. They are then sped up to 25 frames per second and stuck on DVD (so movie is 4 percent shorter and runs 4 percent faster than at the cinema...e.g. LOTR is 180 mins at cinema and 173 mins on PAL DVD).

So simple logic says these movies when on DVD won't be interlaced. There are a few exceptions (I've come across 2) where movies shot on film have been interlaced on DVD. They've been converted from NTSC master tapes, or something, and the length of the movie is not 4 percent shorter. But combing was -everywhere- in DVD2AVI for these DVDs.

TV series are generally shot on video and hence interlaced. There are some exceptions - higher end productions like Pride and Prejudice for example. But regular comedies, modern dramas etc in Europe are usually shot on video. If you have any tv series stick them in DVD2AVI and you'll see what combing is like.

Originally posted by Moondust
I have just done a backup of material that DVD2AVI and bitrateviewer say its interlaced done with interlaced settings and one with progressive settings. I have to be honest to say that I dont see any difference in quality when watching it very closely on my pc monitor. Do you know what usually happens when you encode progressive material with interlaced settings and vice versa?

Encoding progressive material set as interlaced appears harmless - so long as you use zigzag. I've never tried marking interlaced content as progressive, I think that might be a problem when playing back (but I don't know). Using zigzag rather than alternate would be a bad idea though. When I say bad idea, I just mean using the wrong zigzag/alternate setting would just result in a bit lower quality.

Anyway, to finish off, I've been through this little phase of banging my head against the wall about this issue a while back. Take my word for it, if there ain't no combing which sticks out like a sore thumb then it ain't interlaced. That's all there is to it.

[Moondust]

I checked about 10 of my DVDs and not even one had combing in DVD2AVI. All progressive material!

I also did my own little research concerning the 4% time loss. On www.imdb.com it is said that Goodfellas is 145 minutes. My copy is only 139 minutes and a couple of seconds.....exactly 4% less.

So everything you told me is what I am experienceing myself as well. I just did Goodfellas with progressive settings (zigzag) and it came out great.

I got it all now, thanks for your time and effort!
Case closed!

[bobwillis]

Moondust,

The film 'Casino' on region 2 is definitely interlaced. I just wondered if you had it? If so you could see a good example of the combing. I have examined at least 30 DVDs with DVD2AVI, and this is the only one I could find.

It is worth pointing out that whilst nearly all PAL DVDs films are progressive, some do have a few frames of interlaced material - at cut & editing points. The original R2 release of the Great Escape (non-anamorphic) is a good example. However, you do not not have to worry about these (unless you are re-sizing them). They can still be done successfully with progressive settings.

You can certainly encode interlaced material with progressive settings, and like you Moondust, I struggle to see the difference in quality.

One thing that is important though is if you have an interlaced 4:3 letterbox film, and you wish to re-size it to anamorphic using the bicubic resizer or similar, it is necessary to use telecide (in the conversion tab) to remove the interlacing. If you don't, you will see massive interlacing lines tearing through the picture. Once you've used telecide, you can use a progressive template.

This is probably more information than you need (or requested), I just thought I'd let you know in case you ever saw interlaced tearing on resized interlaced material!

Regards,
Bob

[Moondust]

Very helpful bobwillis, thanks a lot!

I plan to examine every single DVD I want to backup thoroughly in order to determine which settings to use.