Deinterlacing / Interlacing Theory and Application

[joejoe04]

Sorry for yet another question on this topic. I have read quite a bit on this site about whether to deinterlace or not. I have gathered the general consensus is that a video should only be deinterlaced if you're planning on putting it on Youtube, etc. because you end up losing detail and future tech should be able to display interlaced video better. That seems fine in theory, but I would like to start transferring VHS to DVD on the side for a little extra money, and I'm just curious if any of you who actually do this give people a DVD with interlaced video as the final product? I ask because if I'd had someone make copies of my VHS's and got the typical interlaced / combed looking video back, I don't think I'd have been happy with the result as someone who didn't know any better. Most people nowadays have LCD's, plasmas, or LED's and it seems to me this could kind of be more of a problem now than when everyone had the old standard def TV's where interlacing wasn't an issue. Just interested to hear what you guys do and if you get complaints from customers unhappy with how interlaced video plays on their screens. Do any of you deinterlace before giving customers their copy?

I know this has long been a discussion and I'm even still torn about whether I will end up deinterlacing my VHS's or not. I understand you lose quality, but interlaced video with lines through it just doesn't look good to me either. I am capturing mine with Virtualdub (no filters or anything for now), converting to DVD with DVDFlick, and burning with ImgBurn. I use a PS3 to play the DVD's and my TV is a 51" Samsung Plasma 720p. As I said, I've read people who say that new tech might be able to play interlaced video better at some point, but right now at least for me, the videos are still poorly displayed with the interlacing lines. Are there any settings I should be changing, either on my TV or PS3 that might help this?

One last question on the topic... When I just hook my VCR up directly to my TV and play a VHS tape, it displays great with no interlacing lines. When I hook it up to my computer through my capture device (Gigaware) and display it through Virtualdub, all of a sudden the interlacing lines are there. There's just something I'm missing here I guess. If the VHS is capable of displaying on my TV without interlacing lines when it is directly connected to it, why is it not possible to capture or record a VHS without the interlacing lines?

I know this is kind of a long post. I'm grateful for any advice anyone can offer.

[manono]

but right now at least for me, the videos are still poorly displayed with the interlacing lines.

If you're seeing interlacing when playing the final DVD to your TV set through a standard DVD player, then you did something very wrong somewhere along the line. Did you resize, by chance?

If the VHS is capable of displaying on my TV without interlacing lines when it is directly connected to it, why is it not possible to capture or record a VHS without the interlacing lines?

The conclusion doesn't follow. Interlaced video plays without the interlacing either because you're playing fields (to an old interlaced CRT TV), or it's being bobbed (for a more modern progressive HDTV). Either way, the source, whether VHS or a DVD made (properly) from that VHS tape, has the interlacing still in it.

No customer will complain if you make them an interlaced DVD from an interlaced source and do it correctly. Do you complain when watching TV shows shot on video?

You say you plan on doing this as a side business?

[joejoe04]

Thanks for your response. No, I did not do any resizing. I captured with Virtualdub, converted to DVD with DVDFlick, burned with ImgBurn. And yes, for some reason I am getting the interlacing lines when I play it on my TV. I have never done or seen it done with different results, so I was under the impression that this was the normal result. I thought I had read the same somewhere, but I must have misunderstood what I was reading. Any ideas as to what I could be doing wrong that might be causing the video to display with interlacing lines on my TV?

I do appreciate your help, but I don't understand why you also feel the need to belittle. I want to learn how to do this for me, and I'd like to eventually get good enough to feel comfortable charging someone a couple bucks to do it too. I didn't say I was going to go start a business tomorrow. I'm a video noob to be sure. I'm just now finding out that 1080p/i stands for progressive/interlaced. Go easy on me

[manono]

I do appreciate your help, but I don't understand why you also feel the need to belittle.

You're right, it was uncalled for and I apologize. But all the time we get these 'professionals' here asking the most basic of questions.

Maybe a short sample of the DVD video might help to figure out the problem. If you don't know how to cut a VOB, open one in DGIndex, use the [ and ] buttons to select a short section (10 seconds worth with steady movement will be plenty). Then File->Save Project and Demux Video. Either upload the resulting M2V here (if less than 30MB) or to a third-party filesharing site such as Sendspace or Mediafire and provide the link.

You've been watching interlaced sources all your life on television - TV shows, VHS tapes, DVDs, etc. None show any interlacing. Your interlaced projects shouldn't either.

[davexnet]

It's hard to say where you went wrong. Perhaps take a 15 - 20 second sample clip of the source, encode it with
DVD Flick and post the source and output video_ts folder to a file hosting site. Somebody will take a look.

Old CRT TV's are interlaced devices and the way the image is displayed is in an interlaced manner;
first the odd field is displayed, lines 1,3,5,etc, top to bottom. Then the even field, lines 2,4,6,etc,.
The even field is 1/60th of a second later. This corresponds to the camera when the video was recorded -
the even field was recorded 1/60th of a second later than the previous (odd) field. So you can see this gives
great fluidity of motion. There wasn't enough bandwidth in the old NTSC system to have 60 complete (progressive)
frames.

[joejoe04]

Thank you both again for your responses! Manono, I can definitely understand how answering basic questions from people pretending to know more than they do would get old quick. I didn't mean to come off that way, I was just trying to be as concise as possible because I had a lot to ask.

Ok, so I did what you said with DGIndex and I've attached the resulting clip. I had told you previously that I was not resizing the video but I did just notice that the video does seem to get resized by DVDFlick. It starts out as a 640 x 480 AVI file, but the resulting VOB file that is created is 720 x 480. I tried to explicitly state a 4:3 ratio in the DVDFlick options, but it still keeps turning out this way. Is this normal or am I doing something wrong? Could this be the cause of the problem?

The original AVI file, even when I clipped it to 12 seconds was way too big to upload, but it displays the same way as the M2V file, with the interlacing lines when there is movement.

Thank you both, and Happy New Year!

[aedipuss]

as to the resize. dvd video in ntsc is 720x480. it is still 4:3 but uses non-square pixels to display the same as 640x480. read the "what is dvd" page - click on the link in the upper left.

[manono]

Thanks for the sample.

I think your problem is probably due to the fact that you encoded interlaced material as progressive. You have a flag-reading player whose deinterlacer doesn't kick in to bob it for you (to a progressive display). You want Nonlinear (not Linear Quantscale), Alternate (not Zigzag Scanning), and Interlaced (not Progressive Frame Type). The fact that the width was increased from 640 to 720 doesn't play a part (although you probably should have capped at 720x480 to begin with, if possible). When I asked if it was resized, it's resizing in the vertical direction that might have been the cause of the interlacing showing on the TV. It turns out it's for a different reason.

Also, you badly need the use of a line TBC in your capture chain. Do you notice how your vertical lines sort of 'wobble'? And the fixed backgrounds sort of move around? That can be fixed. Here, read this:

http://www.digitalfaq.com/forum/video-restore/2251-tbc-time-base.html

Scroll down to the part about S-VHS VCR Line TBC

[joejoe04]

Aedipuss, thanks for reminding me of that. I had read that before, but forgot about it. I will try to capture at 720 width from now on.

Manomo, thanks for the info. Could you possibly elaborate a little on how I would go about achieving nonlinear (not linear quantscale), Alternate (not Zigzag Scanning), and Interlaced (not Progressive Frame Type)? Is this something I need to do while capturing in Virtualdub or while I'm converting the file to DVD? I don't see anything that mentions any of that in any of the options or settings in either program. I just tried to use Bombono and DVDStyler instead of DVDFlick, and both keep crashing for some reason when I try to load my AVI file.

And yes, I'm somewhat aware of the TBC issues as well, though I likely have a lot to learn about that too. Right now I'm just using a $5 junk VCR I bought from Goodwill. If I can figure all this other stuff out, then I'll invest in some better equipment. Thanks for that info too.

[manono]

Could you possibly elaborate a little on how I would go about achieving nonlinear (not linear quantscale), Alternate (not Zigzag Scanning), and Interlaced (not Progressive Frame Type)? Is this something I need to do while capturing in Virtualdub or while I'm converting the file to DVD?

It's something you set in the MPEG-2 encoder. If you're using all-in-one-type programs it may be automatic. But you'll have to choose to encode it as interlaced somewhere - that's the most important setting. Sometimes you'll check an 'Interlaced' box, or, more likely you'll uncheck a 'Progressive' box. Using Alternate Scanning is the second most important thing, but since it is mostly used with interlaced encoding, it may be automatically set once you choose to encode it as interlaced. Linear/Nonlinear isn't all that important, but I'd still suggest Nonlinear if there's a choice.

If using DVD Flick, it looks to me like you choose to encode as Interlaced under Video->Target Format (NTSC (I think)). That's in one guide. Another for a different (more recent?) version shows an 'Interlaced' box in the 'Video Sources' section. Or, give Avs2DVD a try and choose the HCEnc Encoder as you can make all kinds of choices when using that one. But it's also more complex. Good luck.

[joejoe04]

Manamo, Avs2DVD and HCEnc worked great. Next step is getting some better equipment like you said. Thanks for all your help.