To deinterlace or not to deinterlace? Need Help!

[Crow4ever]

Ok, I've read the guides here, read the FAQ, read Luke's Video Guide, and whatever else I could get my hands on - and I'm still a little unsure on a couple of things.

I have an ATI A-I-W 8500DV, and I have tried capping (VHS NTSC) with their software (blows chunks), and with Virtualdub (and the huffy codec seems to do the best job). Vdub does a great job, but the resulting AVI is badly interlaced. Here's where the confusion comes in.

If I encode the avi to a mpg, to be burned to SVCD/DVD and played on my TV with my standalone player, is there any reason to deinterlace the video at all? My understanding is that since the tv is an interlaced source to begin with, the interlacing "artifacts" that would be seen if played on a computer monitor would not be present on the TV. Is this correct?

The reason I don't want to deinterlace is that by doing so, I'm losing the quality of the video. Is this also accurate? And I certainly don't want to change the framerate from 29.97 down to 23.976, because then it just looks choppy as hell.

So I guess what it comes down to is can I just leave the video interlaced for tv-only viewing, or do I need to deinterlace it. And if so, what's the best method (vdub deinterlace filter, changing field order in TMPG, or other)?

[dar1us]

I think this is right

If you encode your interlaced material to SVCD, your TV WILL then deinterlace it, but because of the HUGE differential between the fields, it will compress much more badly, about twice as low quality.

Ideally, you need to preform exactly what the TV does to the video, but before compressing it, as to keep the material good at the end.

For ease of deinterlacing, use SeparateFields,SelectEvery(2,0) [this discards every other field], or Telecide() [more complicated, leaves comb lines if you don't tweak the settings. I have mentioned only these two because I assume you are using DVD2SVCD and they are already in it, I know you can add your own, but I am trying to keep it simple as I have to go and learn now.

-dar1us

[Crow4ever]

So... because the fields are still separated (because of the interlacing), you're losing quality?

Performing exactly what the tv does to the video is exactly what I'm wondering about - and if that requires deinterlacing or not. Your response is a little contradictory. On one hand, you say that the tv WILL deinterlace the video (or, rather, REinterlace it, properly?) But on the other, you say that you have to deinterlace the video.

So what, exactly, DO I have to do?

By the way, the 2 solutions you suggest for deinterlacing (SeparateFields/SelectEvery or Telecide) won't work for me, I don't think. Those are PAL solutions, and as I mentioned, my video is NTSC. Also, I was leaning towards using TMPGEnc to do the encoding. But if DVD2SVCD is a better solution, then I'll use that. But that's just part of my confusion - I need to know IF I need to deinterlace at all, and if so, HOW to deinterlace the best (for NTSC).

- Still confused

[cjv]

You don't lose quality because of the interlacing. You lose quality because captures are inherently noisy (eats bits) and if you are encoding to SVCD, because the max bitrate is capped at @2520, and you are encoding 30fps (eats bits) vs. 24fps. All of this eats bitrate. Encode to DVD and you are fine.

If your source is FILM (24fps), movies, music videos, some tv dramas, you should IVTC your interlaced capture file and then run a pulldown.

If your source is truly 30fps interlaced, and you are encoding to MPEG2 (DVD/SVCD) there isn't any valid reason to deinterlace. The SeparateFields(), Weave() is for NTSC as well btw. You separate your fields, run any smoothers/filters, then weave them back to keep it interlaced. If you ran smoothers without separating the fields, it would end up looking like crap.

Yea, interlaced captures encoded to SVCD will probably not look the greatest, but those are the limitations of SVCD 2500 max bitrate. It's just not enough. Encoding them to DVD bitrates/resolutions will look great. Try CVD 352x480 @2500 as a possible in-between.

Basically, don't deinterlace. Run noise filters and encode to preferably DVD, or try CVD if you aren't happy with the SVCD results.

cjv

[Crow4ever]

Thanks cjv, that definitely clears it up a little.

Basically, I am looking to cap regular shows from the tv, some from tape, some directly from the tv - with the occasional movie from tv thrown in as well. IVTCing the movies is easy, it's the shows that are giving me the trouble.

I am getting a DVD burner in the next day or two, so I will try the solution of encoding the captures to DVD. TMPGenc would probably work best for this method, correct? 2-Pass VBR, no deinterlacing, 9 bits DC component precision, highest quality Motion serach precision? And anything else I should know about the DVD encoding?

The SVCD encoding problem will remain, however, when I'm having a couple of friends capping and encoding some shows for me. In that case it's really no other choice but SVCD because they don't have DVD burners. So how would they go about doing what you suggested with the SeparateFields(), Weave() and any smoothers or noise filters?

I'm almost there... just bear with me on these questions!

[Ookami]

Originally posted by Crow4ever
I am getting a DVD burner in the next day or two, so I will try the solution of encoding the captures to DVD. TMPGenc would probably work best for this method, correct? 2-Pass VBR, no deinterlacing, 9 bits DC component precision, highest quality Motion serach precision? And anything else I should know about the DVD encoding?

The latest TMPGEnc Pro version has improved settings (as oposed to the old ones), also be sure to check the forums for more hints, especially look for postings by the user mb1.

So, 2 pass VBR, no deinterlacing, highest quality motion search, maybe some custom matrices, turn on soften block noise (play with values a bit), Fit2Disc could also help (not freeware!) etc. etc.

One little SVCD hint, when you encode SVCD for TV playback always use FitCD from shh!

Good luck and have fun.

Cheers,

Mijo.

[Crow4ever]

Thanks for the tips, Mijo

However, I'm still a little confused about the deinterlacing needed for SVCD encoding. I've been searching through the forums, and it seems I'm just getting more confused - with all the different opinions on methods etc etc.

I'd like to try the SeparateFields(), Weave() option. Can someone give me a quick runthrough on how to implement this, and what, if any smoothers/filters I need to run with it?

[dar1us]

Have you tried out the DVD2SVCD deinterlacers - i expect that you use that for SVCD conversion. Just select Sep Fields/SelectEvery and encode 2 mins of VIDEO or something abouts that, write it to a CD-RW and enjoy. If you only have CD-r or player wont support RW's, then make as many samples as possible, including 'keep interlaced' ones. See which looks the best.

Also take into account how the actual video has encoded (not just de-interlacing), whether there is substantial more block noise... That kind of thing, adding something like Convo3D could be desired.

Hope it helps, enjoy

-dar1us

[Ookami]

@Crow4ever

When you encode to SVCD don't deinterlace at all! SVCD supports interlaced video.

[Crow4ever]

Okay, well, if I don't deinterlace it, what can I do to improve the picture quality. cjv mentions using SeparateFields(), Weave() - I would like to know how to do this and what kind of improvements this can make to the picture. And should I use that for the SVCD encodes, or both SVCD and DVD?

Also - I've read conflicting things about initial capping resolution. Should I cap at 720x480 or 352x480? I'm just not following the logic on dropping down to 352, especially if I'm going to leave it interlaced.

I capped at 720x480, and tried playing with about every deinterlacing filter on DVD2SVCD, including leaving it interlaced. The results weren't terrible, but they weren't that great either. I'm in the process of trying TMPGEnc now, especially with the soften block noise settings. Using custom matricies was mentioned. Which ones, and how do I use them?

I'd really like more details about SeparateFields, Weave - and maybe some other AviSynth script general help, in the area of capping and what the best scripts are for encoding caps.

[lemon]

Please never deinterlace if the primary destination is a TV screen.
The fact is that TV video is not 30 fps (I know it's 29.97 but I'll say 30) but 60. First field containd odd lines, and second even (or first even and second odd, doesn't mind now) but the important is that they do not refer to the same frame.
So, when you deinterlace, you are not really losing spatial resolution (if you do it well) but you will be always losing temporal resolution, because you are transforming a 60 fps video to a 30 fps one.
You cam make the try. Record something with very fast movement (some sports for example) and then try to record to SVCD or DVD (try in a RW) as interlaced and as non-interlaced. You should be able to see that the interlaced version has much more fluid movements (when seeing it on a TV screen, not in the computer monitor, of course).

[Crow4ever]

Okay, so never deinterlace...

What about using any kind of smoothers or filters (especially for SVCD), or my question on SeparateFields(), Weave(), or any of the other questions...

[lemon]

Separate fields and weave are kinds of deinterlacing. There is a good web page explaining everything about interlacing (the bad and the good things) at www.100fps.com
Applying filters for improving quality can always be done, but it is very dependent on the original images. Filters that can improve quality for some video sequence can really damage a different sequence.
There's no magic solution for using filters. You should visit all forums you can, descriptions of the filters, and basically experiment and try to find what kind of filters are what you need.

[simdavid]

What about using any kind of smoothers or filters (especially for SVCD), or my question on SeparateFields(), Weave(), or any of the other questions...

I played capture interlaced sourced on DVD player for TV from VHS sources.Let me share something with you then.

For Captured sources to be played on TV..DO NOT DEINTERLACED...What u capture from VHS interlaced will be output accordingly to TV to be reinterlaced.That's what TV tech is all about!

Seperatefields,to separate interlace sources 2 fields and convert them to frames.U know upper field laced with bottom field..seperate fields seprate them and make it to frames!It doesn't make your video Fluid if your source is 29.970.it becomes 60 frames per second.And if u wish to convert to SVCD with TMPG..30 frames will be thrown away then to make it NTSC playable!

Applying filters to your video is a matter of preferences..I do not deinterlace my SVCD nor apply any filter becos I like it that way!

So it actually your choice...but do not deinterlaced your material UNless...you have a good reason and you know what u doing!