Ripping DVD's - Why DeInterlace? They were 23.97 or 29.97 fields per second

[SyncroScales]

I was using various free programs or trialware from the download section and DVDFab to rip ISO images or DVD's and have files.

I would say that most of the DVD's I own are NTSC with 23.97 or 29.97 fields per second. Since they are interlaced I left them alone in the option sections before ripping. I noticed there is a DeInterlace function in most programs.

Some DVD's worked well. But Some had problems with the interlacing. So I finally checked the DeInterlaced box with a rip and the picture looked good and normal.

Are the programs not automatically detecting how to correctly interlace the Discs? Or are they being converted to progressive frames? I see no audio and video out of sync issues which usually happens with converting interlaced to progressive.

I looked with GSpot Codec Information Application the files were 23.97 or 29.97fields per second. One that had been deinterlaced said 30.021 fields per second and another was 30.020 fields per second. But the video seemed fine. No Audio and Video being out of sync. It doesn't seem anything changed to progressive.

[hello_hello]

Ripping would normally refer to copying the video to your hard drive "as-is" with a ripping program. It might be ripped to vob files or a single ISO file etc but nothing's re-encoded, just copied (ripped).
Some "ripping" programs rip and convert at the same time (or they're able to). Technically that's not just ripping and the distinction is important. If that's the case they could be doing anything when converting.

There's no reason why you can't encode the video interlaced, although de-interlacing first tends to be the way most people do it. Converting interlaced to progressive (de-interlacing) shouldn't effect the audio sync at all.

Keep in mind NTSC can be interlaced "video" at 29.970 frames per second or 59.940 fields per second (same thing, however you look at it), or "film" at 23.976 frames per second that's converted to NTSC using 3:2 pulldown. It also ends up being 59.940 fields per second. It's a method that takes advantage of interlacing fields, but it's not the same thing as "interlaced".

http://en.wikipedia.org/wiki/Interlaced_video
http://en.wikipedia.org/wiki/Three-two_pull_down
http://en.wikipedia.org/wiki/Telecine#Reverse_telecine_.28a.k.a._inverse_telecine_.28I...se_pulldown.29

NTSC "video" would normally be de-interlaced to 29.970fps progressive. NTSC "film" wouldn't be de-interlaced as such, but inverse telecine is applied to recover the original progressive frames and the output would be 23.976fps progressive. Some programs might have a single "de-interlacing" option that either de-interlaces or applies inverse telecine as the program sees fit.

Because NTSC video is always 59.940 fields per second, it can be a combination of "video" and "film". Many conversion programs output a constant frame rate (23.976 or 29.970fps) and the chosen frame rate is based on the majority of the source type. For example, if it's mostly "film" the output will be 23.976fps progressive and any "video" sections are also converted to that frame rate. Some programs output a variable frame rate. Each method has it's pros and cons but much of it depends on the program in question analysing the video and getting it right, which as you seem to have discovered, isn't always the case. If a program reports odd frame rates for the encoded video it could be variable frame rate and the program is reporting the average, or it could simply be getting it wrong.

That's the basics of it for NTSC, but there's all sorts of horrors that can be inflicted on video as it's converted to DVD format. If you're needing help, you're going to have to be fairly specific. Providing a small sample of the original video is often the best idea. There's no "one size fits all" correct answer, and no way to know whether a program is getting it right without knowing exactly what it's doing, which might mean looking at a log file, along with a sample of the original video etc.

Your post here is effectively asking the DVD conversion equivalent of "how long is a piece of string?"

PS NTSC DVDs can contain 23.976 frames per second progressive "film". "Pull-down flags" would be used to tell the DVD player to apply 3:2 pulldown on playback (rather that it being encoded that way), but the end result is the DVD player still outputs 50.940 fields per second. If that's the case the pull-down flags could be ignored and the progressive 23.976fps "film" could be encoded "as-is", no de-interlacing or inverse telecine required. However a DVD can still be a combination of "Video" or "Film" etc as the output is technically always 59.940 fields per second for NTSC. Hopefully that makes sense.....

[smrpix]

I noticed there is a DeInterlace function in most programs.

What "most programs" are you using and what is your end goal? You only need to deinterlace for web upload.

[SyncroScales]

More reading. It doesn't stop.

Thanks for the info. I made the mistake of saying ripping not converting. Most people say "ripping the files or disc" and mean converting.

Programs: VidCoder, AnyDVD HD (which seems important the more I understand it), AutoGK, MakeMKV, Handbrake, DVDFab

Not really for this post: CloneDVD/BD/CD, VLC media player, Internet Downloader, EagleGet, Action!

So I will try one or two more things with the programs I am using. I was converting some disc folders and iso images into mkv, mp4, avi, etc. I think I will go back and test with some more option. I think it's detelecine. After this I can post some screen shots or clips.

Why would I decomb, denoise or deblock when using Handbrake? Is this another broad question?

[newpball]

I was using various free programs or trialware from the download section and DVDFab to rip ISO images or DVD's and have files.

I would say that most of the DVD's I own are NTSC with 23.97 or 29.97 fields per second. Since they are interlaced I left them alone in the option sections before ripping. I noticed there is a DeInterlace function in most programs.

Some DVD's worked well. But Some had problems with the interlacing. So I finally checked the DeInterlaced box with a rip and the picture looked good and normal.

If you want to store DVDs with the original quality on your PC then you should obviously not deinterlace (although it is possible to deinterlace lossless).

If you do decide to deinterlace for whatever reason please frame double, do not throw away valuable frames!

[LMotlow]

Agreed. Your best archive is the original VIDEO_TS folders or an ISO.

I would say that most of the DVD's I own are NTSC with 23.97 or 29.97 fields per second.

No, better not say that. DVD's are never encoded at 23.97 fps. They are 29.97 interlaced frames per second, period, which can mean 59.94 fields per second playback (NTSC) -- or 23.97 progressive fields per second film-based video with 3:2 pulldown (i.e, interlaced) for 59.94 fields per second playback.

[manono]

-- or 23.97 progressive fields per second film-based video with 3:2 pulldown (i.e, interlaced) for 59.94 fields per second playback.

You mean to say '23.97 progressive frames per second film-based video with 3:2 pulldown (i.e, interlaced) for 59.94 fields per second playback'. Him writing all that 'fields per second' nonsense must have thrown you off.

[LMotlow]

Yep, that's what I meant.

[hello_hello]

Why would I decomb, denoise or deblock when using Handbrake? Is this another broad question?

You'd probably only use denoising if the source is particularly noisy. Denoising is always some sort of compromise between removing noise (film grain etc) and blurring detail. The less noise there is though, the easier the video will be to compress (smaller file sizes for a particular quality). If I remember correctly AutoGK always uses a denoiser but it's very light-weight in that it only removes very fine noise so it doesn't have much of an effect on picture detail. I think Handbrake lets you choose the denoising strength and the lightest denoiser would probably be similar to AutoGK's denoising.
Blocking can be caused by too much compression. This is a fairly exaggerated example in that I don't think you'll see anything that bad on DVDs too often. In fact most of the time you probably won't see any at all and deblocking will also blur detail so I rarely use a deblocking filter.

I don't use Handbrake and I don't understand it's de-interlacing options all that much.

If the source is purely interlaced, enabling the de-interlacing filter would output progressive video at 29.97fps (NTSC) or you could choose "Bob" as the de-interlacing method and that'd give you 59.940fps progressive which should result in much smoother motion. For purely telecined sources I assume you'd use the Detelecine filter, but I don't really understand how to work with mixed content properly (mix of "film" and video" etc), or even how to easily determine what the source is, as I think the only way to preview it using Handbrake is to encode some of it. If in doubt, I think Decomb (some sort of "intelligent" de-interlacing) with "same as source" and "variable" as the output frame rate options is the "set and forget" method, but maybe a regular Handbrake user will come along and clarify.

[SyncroScales]

Thanks for the information and replies.

LMotlow and manono: My mistake too many fields per second typing.

Before I read any replies I read a little bit of the Handbrake manual/help file. That explained a lot of what all the options of detelecine, decomb, deinterlace and deblocking, etc meant. Even if I don't use Handbrake, I think reading the manual might give me a lot of info. It also explained things about 3:2 pulldown and shows images or animated images to explain.

What program(s) do you use hello_hello?

I am doing some tests with 29.97 frames per/sec and 59.940 frames per/sec with DVDFab and Handbrake.

If anyone wants to know which discs these are here is the web-site. I am sure there was film turned into video and film mixed with video. http://www.mimedance.com/store/main.html - The documentary and instructional have been a good learning curve while trying to back-up the material and in general to learn about this type of theatre/performance/etc. I have not finished the book though.

[hello_hello]

What program(s) do you use hello_hello?

MeGUI 99.99% of the time.
It's an AVIsynth based GUI and AVIsynth expects constant frame rate video (there's ways around it, but generally you'd work with constant frame rate video).
MeGUI will open the video, index it, then open the script creator with a preview (it creates AVIsynth scripts for you then uses them to encode). It'll also analyse the video for you and choose the de-interlacing method it thinks most appropriate (it's not always right, or doesn't necessarily always do it the "best" way). The preview lets you step through the video and look for combing yourself so if you want to you can determine the source type and choose your own de-interlacing method.

Ultimately, the video is converted to a common frame rate, which isn't always ideal, but for movies and TV shows they tend to be all one type or another (film or video) with maybe the opening studio logos being different to confuse things.
Mind you I'm in PAL-Land so I don't have mountains of NTSC experience.

MeGUI and AVIsynth are a different ballgame. More of a learning curve. I assume Handbrake was designed to provide good results without much user knowledge, and it probably does that job well. That's also a limitation if you want full control over everything, which can actually be dangerous if you don't know what you're doing. I've stuffed up encodes countless times. Or months/years later I've re-encoded the same video again while thinking I should've done it that way originally, but you learn as you go.