Is there such a thing as a simple answer? Interlaced &

[djworkit]

Ok, I've literally searched and read around for a good 5-6 hours in total and still can't find a definitive answer (maybe there is no such thing).

Scenario: I'm about to purchase a miniDV cam and I will be editing video from this cam. It looks like what I will be getting will have 500-520 lines of res. I live in north America (NTSC land).

Problem: It sounds like, even with a miniDV cam, almost any video I transfer to my PC (via VGA capture card or firewire) will come in interlaced form. To sum it up quickly, I would like to view my video both on my computer's monitor and on TV. (I prefer just double-clicking on a file from my store of media content, wheras the rest of the family/extended family would prefer watching the video off a home DVD player)

Things I've read so far...:
1. That whether you keep the interlace or not depends on whether you want to watch it on a progressive or interlaced display. (Is it at all possible to have both worlds here?)

2. That de-interlaced [I've been using G... (somebody's) "Smart Deinterlacer) in Virtual Dub] video will be half the quality of the original [no video resolution or framerate was given here].

3. That de-interlaced video will play fine on NTSC interlaced TV's (but I did not see a framerate listed for this quote)

4. That de-interlaced video will play on interlaced TV's but will look bad

5. And finally, that in 2008 new laws (relating to TV manufacturing in the USA) will go into effect that essentially do away with NTSC, with HDTV taking its place [but I don't know if this has any bearing on interlacing or not because I know lots of HDTV's right now are "1080i" (i-is for interlaced).

My goal: To start editing family video (coming from miniDV cam), storing it all on a nice big hard drive along with photos, and every now and then placing some of the video onto DVD and sending it off to family members (also in USA) for them to watch at their own homes. An additional goal of mine is to learn good vido editing practice that is as future-proof as possible without having to keep around gobs and gobs of uncompressed video. (just to state it simply )

Thanks in advance for any post that might point a newbie in the right direction !

[djworkit]

P.S. I don't have a DVD burner, and my DVD player doesn't play S-VCD so I am unable to test out any video that I've already edited so far.

[Hardlok]

The straight and simple answer is that all your fears are unfounded as long as you keep the content in high res mpeg2/dvd (7xx by 4xx pixels per frame) format with low compression levels.

The following factors are what mainly affect the quality of the mpeg2:

1) Frame size used when transcoding: e.g. 720x480 is better than 320 x 240 pixels per frame
2) Compression: all things being equal, a 5GB video file converted to 3GB should look better than the same file compressed to 1GB using the same encoder.
3) Encoder quality: some software produce better quality than others at the same compression levels.
4) Editing treatment: If you don't follow established methods for preserving the quality of the source material during the editing processes, the final product may look bad even at high res, low compression
5) Note that dvd-quality digital video is inherently non interlaced and is the reference. This is because non interlaced video can be output as interlaced video with fewer quality consequences than the converse.

So let's say you capture your video and convert it into a high res low compression non interlaced mpeg2 format. Now when you play it back, the image quality will depend on playback devices. On the pc, it is safe to say that you will have a higher chance of viewing the good quality of the source, because modern pc graphics cards and monitors are non interlaced. Factors that affect video quality on pc playback:

1) Graphics adapter hardware: A solid DAC, good hardware decoding of mpeg, good filters, etc, will yield a great image.
2) An Lcd display should be better than a CRT. An all-digital LCD connected to the digital DVI output of your pc is usually better than an analog LCD. A larger display may yield better enjoyment than a small display (unless your source video is inherently low res)
3) The refresh rate of your monitor must be non-interlaced, at a high refresh rate of 75Hz or more. The rest of the image quality variables will rest on the dot pitch, the colour calibration settings, glare-reduction features of the screen, etc.
4) The playback software/decoder algorithms will of course affect the playback quality.

The playback quality is more variable with tvs connected to dvd players.
The best way to get good image quality is to minimise processing of the content. For example, avoid setting the dvd player to output progressive scan signals to a tv that is set to process any signal with its own progressive scan algorithms. The general guidelines for good image quality are:

1) Use a 100Hz tv for best results. An interlaced tv will not yield the most stable, flicker free video regardless of whatever progressive scan video source and dvd player you use.

2) The dvd player does not need to be the progressive-scan type if your tv already converts incoming signals to progressive. However, if your dvd does have progressive scan output, you can choose to disable either the deinterlacing circuit of the tv or that of the dvd player. Only one device should be deinterlacing the video signal.

3) One strong variable that affects image quality is the deinterlacing circuitry being used on progressive scan devices. Not all progressive scan tvs are made equal. Same applies to dvd players. You will just have to make do with whatever tv and dvd player combo you have, but the general rule if you want to improve video playback quality, is to get equipment with good scalers/deinterlacers.

4) Calibrate your tv and dvd player with a good test disc (e.g. AVIA or DVE) and use the best quality connections (e.g. component video is better than S-video, composite video is not recommended; while straight digital connections via DVI can be a notch up in quality)

IMHO, the preferred video format for playback on both the tv and pc, in your case, are: DVD mpeg2. Burn the material into a standard DVD and it can be viewed on either platforms. As you don't have a burner, you will just have to get one. They are affordable now, and your desire to get good quality video has a price.

If getting a dvd burner is out of the question, then either restrict viewing of the video on the PC, or output to cdr as high bitrate high res divx (in which case you still need to get a dvd player that can play divx). Alternatively, you can use the pc as the playback device by connecting it to the tv via s-video or component-video adapter. If your final video clips are relatively short, you can also burn them to cdr in mini-dvd format, or use low compression high res MPEG1. But that would mean your dvd player must support these well, and you may need to split the video into two or more CD-Rs.

If you really do not want to spend much money buying a new dvd player, perhaps you can try SVCD at high bitrates (and the video may have to be spanned over 2 or more cdrs). This is the last resort, but it will be unlikely to do justice to your dv-cam's video.

(Disclaimer: my comments may have been generalized at certain points to ease understanding for djworkit. Please beware that my over-generalizations may cause misunderstandings for others looking for answers to their peculiar problems).

To sum it up quickly, I would like to view my video both on my computer's monitor and on TV. (I prefer just double-clicking on a file from my store of media content, wheras the rest of the family/extended family would prefer watching the video off a home DVD player)

Things I've read so far...:
1. That whether you keep the interlace or not depends on whether you want to watch it on a progressive or interlaced display. (Is it at all possible to have both worlds here?)

2. That de-interlaced [I've been using G... (somebody's) "Smart Deinterlacer) in Virtual Dub] video will be half the quality of the original [no video resolution or framerate was given here].

3. That de-interlaced video will play fine on NTSC interlaced TV's (but I did not see a framerate listed for this quote)

4. That de-interlaced video will play on interlaced TV's but will look bad

5. And finally, that in 2008 new laws (relating to TV manufacturing in the USA) will go into effect that essentially do away with NTSC, with HDTV taking its place [but I don't know if this has any bearing on interlacing or not because I know lots of HDTV's right now are "1080i" (i-is for interlaced).

My goal: To start editing family video (coming from miniDV cam), storing it all on a nice big hard drive along with photos, and every now and then placing some of the video onto DVD and sending it off to family members (also in USA) for them to watch at their own homes. An additional goal of mine is to learn good vido editing practice that is as future-proof as possible without having to keep around gobs and gobs of uncompressed video. (just to state it simply )

Thanks in advance for any post that might point a newbie in the right direction !

[djworkit]

5) Note that dvd-quality digital video is inherently non interlaced and is the reference. This is because non interlaced video can be output as interlaced video with fewer quality consequences than the converse.

Thanks a lot for the reply... I just learned a lot.
I think I found where my thinking went wrong... tell me if this is correct (or not):

So (once I get a DVD burner) when I burn an mpeg2 (that has been deinterlaced=progressive) to a DVD and stick it into my home DVD player (which is non-progressive=interlaced) which then outputs to my non-progressive TV, the video image coming out of my TV will look fine (as in, at least VHS quality but obviously less crisp than on my computer monitor).
*is this correct?

I guess I was unaware that either my DVD player or TV (or both?) automatically convert anything going through to interlaced video.

Is this where I went wrong?

Thanks

[Hardlok]

Hi

If you do get a dvd recorder and produce a standard dvd, you will get clear interlaced video on your tv. It won't be as good as non-interlaced video, but it will be clear.

Your next step up is to get a 100Hz tv that can display non-interlaced video. The image will not flicker as badly, will be less of a strain to the eyes, and depending on the deinterlacing circuitry, will look smoother and more 3-D than on your current tv.

Watching the same dvd on your pc will yield very good results without you spending any more money on the tv...

You said: "I guess I was unaware that either my DVD player or TV (or both?) automatically convert anything going through to interlaced video."
Actually, the interlaced tv doesn't convert anything -- it simply is not capable of displaying non-interlaced video, so your dvd player's default interlaced output suits the tv fine. (ie, although the dvd has non-interlaced video, your interlacing dvd player will output the video in interlaced format). To give you an example -- if you got yourself a progressive scan dvd player and set it to output non-interlaced video to your tv, you'll see nothing! (progressive scan = non-interlaced video)

On the other hand, a progressive tv will convert signals: from interlaced to non-interlaced. Some progressive tvs can be set to even process incoming progressive signals, using its own algorithms -- e.g. Phillips Pixel Plus. This extra processing may or may not be desirable, but it is an option.

Have fun!

5) Note that dvd-quality digital video is inherently non interlaced and is the reference. This is because non interlaced video can be output as interlaced video with fewer quality consequences than the converse.

Thanks a lot for the reply... I just learned a lot.
I think I found where my thinking went wrong... tell me if this is correct (or not):

So (once I get a DVD burner) when I burn an mpeg2 (that has been deinterlaced=progressive) to a DVD and stick it into my home DVD player (which is non-progressive=interlaced) which then outputs to my non-progressive TV, the video image coming out of my TV will look fine (as in, at least VHS quality but obviously less crisp than on my computer monitor).
*is this correct?

I guess I was unaware that either my DVD player or TV (or both?) automatically convert anything going through to interlaced video.

Is this where I went wrong?

Thanks

[FulciLives]

Your standard DV cam or Digital8 cam will only do interlaced video. You should leave it that way.

DO NOT DE-INTERLACE IT

HDTV sets can do interlaced video just fine. They have chips made especially for deinterlacing that is better than anything you can do with any filter on your computer be it VirtualDub or AviSynth etc.

As far as watching the INTERLACED video on your COMPUTER MONITOR you can use either PowerDVD or WinDVD which will deinterlace on-the-fly.

- John "FulciLives" Coleman

[djworkit]

Ok, Thanks for the reply(s) again

I was wondering about that (computer software DVD players that deinterlace on the fly). Ok, so, according to you Fulci, I should keep my video content (from miniDV cam) all interlaced all the way to the end mpeg2.

1. Will TMPGEsomething something encode an already-edited uncompressed AVI to an Interlaced Mpeg2? (I'll figure out the field order and all the other minor settings once I'm actually ready to burn stuff, I won't bother you guys about that here...)

And finally, ARE YOU SURE? I only ask again b/c once I get the needed equipment, I plan to do lots of video edits and I hope to have a method ready to go so I can "hit the floor running" so to speak. I also hope not to come back here too often... meaning once I develop a method for this stuff I won't want to change it

[FulciLives]

Ok, Thanks for the reply(s) again

I was wondering about that (computer software DVD players that deinterlace on the fly). Ok, so, according to you Fulci, I should keep my video content (from miniDV cam) all interlaced all the way to the end mpeg2.

1. Will TMPGEsomething something encode an already-edited uncompressed AVI to an Interlaced Mpeg2? (I'll figure out the field order and all the other minor settings once I'm actually ready to burn stuff, I won't bother you guys about that here...)

Yes. You can use TMPGEnc Plus to convert DV AVI to MPEG-2 for DVD.

And finally, ARE YOU SURE? I only ask again b/c once I get the needed equipment, I plan to do lots of video edits and I hope to have a method ready to go so I can "hit the floor running" so to speak. I also hope not to come back here too often... meaning once I develop a method for this stuff I won't want to change it

There is no good reason to deinterlace video for normal use. What I mean to say is that there might be some oddball special situations where it might be a good thing but mostly it is NOT a good idea to deinterlace.

- John "FulciLives" Coleman

[djworkit]

Me again... I want to make sure I don't offend anybody throughout this discussion. I feel I'm getting conflicting answers, which is probably the same reason I looked and looked in the first place (and ended up here).

Maybe it would help if someone could explain to me why it is better to either keep interlacing or deinterlace and why?

_Thanks again

[Hardlok]

Hi

Maybe you can take a look at this page:
http://www.lordsmurf.com/capture/interlace.htm

and this: http://www.100fps.com/

Basically, video sources are interlaced. The best modern dv cams come with progressive output. Assuming you are not using such new dv-cams, I'll assume your dv output is interlaced.

To capture the video into a digital format for editing/compression to mpeg2, you can choose to keep the signal interlaced, or as is the practice with standard commercial dvds, deinterlaced (as the studio's video sources are non-interlaced, ie. film).

As the website above recommends, you may not want to practise commercial standards as your dv-cam is not progressive, and neither are your viewing devices. Choosing the wrong deinterlacing algorithms *can* result in worse video than keeping it interlaced. My take is that if you experiment and choose the right encoder, this point is not so critical. I also feel that deinterlaced video on dvd is obsolescence proof, and is useful if you pass the video to friends and family who have progressive display devices. And, if you upgrade your display devices in future to progressive scan your dvd will be ready for you.

Maybe you can try both methods and decide for yourself which is better (because the image quality between keeping the video interlaced or deinterlaced, can be subjective)

Me again... I want to make sure I don't offend anybody throughout this discussion. I feel I'm getting conflicting answers, which is probably the same reason I looked and looked in the first place (and ended up here).

Maybe it would help if someone could explain to me why it is better to either keep interlacing or deinterlace and why?

_Thanks again

[djworkit]

Ok, thanks a lot guys. I'll try them both out once I get my equipment. And yes, I do plan on one day having a nice progressive HDTV (as well as equipment to match)... you brought up a nice point there I hadn't thought about yet.

And thanks for the links (I already made my way through those two yesterday )

[bugster]

I am with FulciLives on this one. DO NOT DE-INTERLACE. It is only asking for trouble.

An NTSC DV cam use a resolution of 720*480 Interlaced.

NTSC DVD resolution is 720*480 and may be interlaced or progressive.

Converting interlaced to progressive is prone to error and the introduction of artefacts, its not worth the pain.

[FOO]

The short answer is that it's impossible to deinterlace.
Think about it , you have two fields from different points in time
If anything moves , including the camera , mixing those
fields will be a mess .

[SLK001]

Another short answer: It all depends on your source. If, like FOO states, your camera captures FIELDS at DIFFERENT POINTS IN TIME, then you can not deinterlace this and get acceptable results. But if your camera captures complete FRAMES, then converts the captured video to 29.97 by hard telecining on the fly, then this CAN be deinterlaced with very good results.

As for the software DVD players deinterlacing "on the fly", well, this just doesn't happen. What they do is de-pulldown on the fly, which means that they just don't apply the 2:3 pulldown necessary for a standard TV and just play the video as progressive (24fps). They will do this if the video is progressive only - if the video is hard telecined, then they will play them as they play on a standard TV, interlace lines and all.

[djworkit]

Another short answer: It all depends on your source. If, like FOO states, your camera captures FIELDS at DIFFERENT POINTS IN TIME, then you can not deinterlace this and get acceptable results. But if your camera captures complete FRAMES, then converts the captured video to 29.97 by hard telecining on the fly, then this CAN be deinterlaced with very good results.

Oh, ok. I think I get it now. So trying to de-interlace video that actually started off purely interlaced (as in, fields coming from DIFFERENT points in time making one frame) is, if by definition only, impossible.
However, if the video started off with full-frame-at-one-point-in-time captures, then there it is possible to de-interlace to get more crisp results (though fast movemens in the video may suffer a *less-smooth* look), and the trick is just to find out how to de-interlace the video correctly. I don't currently know whether "de-interlacing correctly* means using a de-interlace filter or de-pulldowns or inverse teleclining, but one day I will know and I WILL BE GOOD AT THIS!

Now I'm currently reading specs and reviews of miniDV cams, and some of the cams state "frame captures" and then do the "hard teleclining" to 29.97fps as you described (yet both "fields" come from the same point in time).

And then, of course, there are the cameras that don't mention this at all (and capture interlaced, using fields that come from 2 different points in time).

So, ultimately, if I was able to choose between these two types of cams (Which I am... since I haven't bought one yet ) would you guys suggest (for the purpose of editing, then being able to view crisp video on a computer monitor... as well as viewing [as good a picture as my junky TV will put out] decent video on my NTSC, non-progressive, non-HDTV television) that I go with a miniDV cam that actually captures in frames?
I know that currently, any video I transfer from the cam to my compter will come through interlaced (even over firewire), but it sounds like de-interlacing will be a jiffy (simple) if the camera captured each field of one frame at the same point in time. So should I look for a cam that states "Frame Movie Mode" ?

Thanks again!

[SLK001]

For what you want, get a camera that captures progressive frames at 24fps, and gives you the option of storing the video at 24fps on the tape (but I don't know if such an option exists). At the very worse, a hard telecined video can be easily IVTC (well, maybe not easily...).

[tito13kfm]

There is no good reason to deinterlace video for normal use. What I mean to say is that there might be some oddball special situations where it might be a good thing but mostly it is NOT a good idea to deinterlace.

- John "FulciLives" Coleman

This should be a sticky...

[JohnWestbury]

(as in, fields coming from DIFFERENT points in time making one frame) is, if by definition only, impossible.
However, if the video started off with full-frame-at-one-point-in-time captures, then there it is possible to de-interlace to get more crisp results (though fast movemens in the video may suffer a *less-smooth* look),

Not impossible, just lower quality.

Also, you don't deinterlace frame-based or progressive because they are not interlaced.

For the highest quality, stick with the output format of your camera (or what ever).

[SLK001]

(as in, fields coming from DIFFERENT points in time making one frame) is, if by definition only, impossible.
However, if the video started off with full-frame-at-one-point-in-time captures, then there it is possible to de-interlace to get more crisp results (though fast movemens in the video may suffer a *less-smooth* look),

Not impossible, just lower quality.

I can't for the life of me figure out where you got this information. It is not lower quality. Performing an IVTC allows you to allocate more encoding bits to unique video sequences, since you don't have to encode various fields twice (which you would if your video was hard telecined). This can result in a higher quality encode than the same video encoded with the repeated fields.

There is no good reason to deinterlace video for normal use. What I mean to say is that there might be some oddball special situations where it might be a good thing but mostly it is NOT a good idea to deinterlace.

- John "FulciLives" Coleman

And this statement couldn't be farther from the truth. There are many reasons (all good) to deinterlace video that has been hard telecined. However, there are situations where it is not desirable to deinterlace, but it depends entirely on the source. The video camera with seequential field recording is one.

[FOO]

All you have to do is go look on doom9 , and you will find
that a bunch of people have spent years developing de-interlacing
algorithms and they are still at it. Those guys aren't stupid
(maybe crazy) but they are having a hard time with it.

Go look at www.100fps.com for interesting stuff.

[Sulik]

There is a LOT of mis-information about deinterlacing out there, and a lot of confusion.
First of all, deinterlacing is totally different if you are doing it at encode time or at decode time.

Deinterlacing is BAD when capturing.
Deinterlacing is GOOD when rendering.

If you deinterlace when capturing, you're basically throwing away half of the temporal information, and motion will be less smooth (asides from deinterlacing artifacts). The only exception to this is if you're encoding at a low bitrate, where keeping it interlaced will create more compression artifacts (smooth motion vs less compression artifacts, take your pick), or if the decoder doesn't support interlaced content very well (DivX comes to mind).

If you're displaying an interlaced sequence on a progressive display, the decoder will be able to deinterlace each field separately (usually done in hardware overlay), and you'll have a 60p video output (each field is deinterlaced to a frame with full vertical resolution, then shown separately). If you deinterlaced at capture time, you will only have 30p (with either one field that was removed, or both fields blended together, depending on the deinterlacer).

[FOO]

You are saying that de-interlacing consists of
decimating fields only . Bullshit
there is a whole science about it - detecting movement
and smoothing only those areas , interpolating fields etc.

And how the hell does it matter when you do it ?

[lordsmurf]

Never deinterlace an interlace source. If you want to maintain best quality, that is. Period.

Only exception is reverting by way of IVTC. But not all sources originate from that method. In fact, pretty much only interlaced commercial DVD will allow it. Even movies on VHS, tv, satellite, etc, are so far removed from the fim source that IVTC often doesn't work perfectly, and leaves deinterlace aritifacts.

Simple answer: it is impossible. You can do okay, but it's not perfect. Perfect method is to leave it alone.