to deinterlace or not for viewing on TV

[georgia_dutchman]

I have been capturing home videos from SVHS at 640X480 and converting to MPG2 or DIVX with fair success. Using VDub to deinterlace/smooth as needed produces avi's with pretty good quality when played on the PC. I am just now starting to put these video's onto CDR in VCD format with the intent of being able to play them on DVD players connected to televisions (NTSC). The VCD format is 320X240, yet NTSC is of course interlaced and here is where I get confused. My original capture is at 480 so I should be getting both fields from each frame (hence the need to deinterlace). How does the conversion to VCD (I use TMPGEnc) deal with the interlaced frames? Does TMPGEnc throw away every other field to get down to 240? Or is it actually producing 320X240 at 60 fields per second? Finally, if it can maintain or recreate the interlaced output which would be ideal for viewing on NTSC television, will I destroy that capability if I run the Vdub deinterlace filter prior to converting to VCD? (Sorry about the long post, just trying to be clear...)

[mpack]

I can't answer questions about what TMPGEnc actually *does*, since given the lack of documention the only person who can give definitive answers to that sort of question is the author.

However, I can tell you that, regardless of what TMPGEnc does, standard VCD does not understand interlaced video, nor does the MPEG1 encoding format used by VCD. The NTSC video is stored on the disk at 320x240x29.9 fps - that's fields or frames per second, it makes no difference since there's no interlacing.

If you want to use MPEG2 and interlacing you have to use SVCD, in fact that is the main reason SVCD was invented.

[georgia_dutchman]

Ok, thanks mpack,,, that cleared up some of my confusion.. I realize I want to be going to SVCD format but my original question still stands. Since SVCD (& MPEG2) support interlaced, am I hurting the quality of the final SVCD video if I deinterlace the captured video before converting to SVCD? Thanks

[ktnwin]

You do not have to de-interlace the video before encoding to MPEG-2 (SVCD).

Software like TMPGEnc has a field for you to specify the format of the input video, in this case, "interlaced". It knows what to do based on your input.

You have to tried the field order (odd first OR even first) to achieve correct encoding and obtain good results.

[anti-alias]

I'm not the expert on this but I would think you would want to preserve the interlacing. Just make sure you get the Field order right in TMPGenc! If you get it backwards, your resulting MPEG-2 will "flutter" whenever there is motion in a scene.

I tried deinterlacing and it looked ok but not as sharp as interlaced SVCD (on the TV). However, I was starting with an MPEG2 captured from DVCII. I don't know much about converting AVIs / DV and how the interlacing works on those formats.

[KSJ]

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On 2001-10-16 16:06:55, anti-alias wrote:
I'm not the expert on this but I would think you would want to preserve the interlacing. Just make sure you get the Field order right in TMPGenc! If you get it backwards, your resulting MPEG-2 will "flutter" whenever there is motion in a scene.</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

I don't understand...what is "field" order? Where do I find this in TMPGenc? Is there something in the "How to" guides about it? I am in the process of fumbling my way through this thing, and last night for the first time I encoded with TMPGenc to SVCD, and the picture as indeed fluttery as you describe (I've also used the terms "jumpy" and "jittery&quot in the motion sequences. And throughout the whole thing, the picture shakes a bit, like the cameraman had low blood suger while he was filming. Is this related to the same problem?

KSJ



<font size=-1>[ This Message was edited by: KSJ on 2001-10-16 16:13:32 ]</font>

[KoalaBear]

Interlacing is one of those things that you don't really want to get into unless you intend to become an expert, because there are too many nuances (temporal versus vertical resolution, for example) that simply don't lend themselves to a "do this" or "do that" sort of truth.

Suffice it to say that in MPEG-1 (VCD) interlacing is an issue, and in MPEG-2 (SVCD) it's not. If you're producing video in one of these formats and you hit a blocking point, report it here, because there are plenty of guys who will help you over the hump.

But if you want people to explain to you the theory so you can pick and choose whatever techniques you think will be the most applicable, look elsewhere. Most of us are concerned with making video discs for ourselves and our family and friends; we're not here to do fundamental research to save you the trouble of figuring out the answer on your own.

Except KSJ. You've got me stumped. Are you a male or female? How old are you? Not that these questions are relevant in any practical way, I just want to know for demographic reasons.

[georgia_dutchman]

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On 2001-10-16 18:45:59, KoalaBear wrote:
"Most of us are concerned with making video discs for ourselves and our family and friends; we're not here to do fundamental research to save you the trouble of figuring out the answer on your own."
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

Making video discs for family and friends is all I'm after also. Thanks to all of you for providing the answer to my question... I didn't expect anyone to go off and knock themselves out doing "fundamental research"!
Georgia_Dutchman

[KoalaBear]

No offense was intended, Georgia, I promise. But I'll be a little more specific about what I meant.

Very often people who are new to the scene will ask questions like, "If I get decent results at XKb/S, will my results be any better at X+YKb/S?" which implies that everyone reading the message should drop what he's doing to perform an 8-minute experiment in order to give the querant an answer he could just as easily have gotten himself.

By the same token, it's pretty easy to take a short segment of video and process it both ways, interlaced and non-interlaced, burn it to a CD and watch it on both the PC and the TV in order to determine whether the deinterlacing step was actually necessary for the video segment under consideration.

It's an 8-minute experiment, yet rather than actually perform the work and gain truly useful experience in the process, people would rather ask the "experts" for their opinion (who would have to perform the same experiment in order to honestly answer the question) than be burdened with the experiment themselves.

Now, if you've done these experiments and you want to hash out whether blending is a better deinterlacing strategy than weaving, I'm happy to take the argument up with you. There's evidence to support the position that 240 lines doubled to 480 is just as pleasing to the eye as 480 lines by itself (in fact, I have a very good anecdote about this) which is relevant to the original question. But c'mon.

Why should somebody have to give someone else a theoretical background in deinterlacing in order to answer what is ultimately a subjective question?

What you've asked you can discover for yourself as easily (more easily, in fact) than anyone else can discover it and report it back to you.

(And for the record, I should have said "pure" research as opposed to "fundamental" research. Pure research is when you find out why the sky is blue because you're curious about it. Applied research is when somebody pays you to come up with the answer.)

As for KSJ, though, the questions still stand.


<font size=-1>[ This Message was edited by: KoalaBear on 2001-10-17 00:32:43 ]</font>

[anti-alias]

KSJ -- Click setting, click "Advanced" tab. Should see

Video Source Type: Interlace
Field Order: Top Field First (field A) --or-- Bottom Field First (field B)

I can't say if this is causing your jittery video though ... lots of stuff can go wrong.

[KSJ]

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On 2001-10-16 18:45:59, KoalaBear wrote:
Except KSJ. You've got me stumped. Are you a male or female? How old are you? Not that these questions are relevant in any practical way, I just want to know for demographic reasons.
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

Excuse me for being leery of what your "demographic" reasons are. Hopefully you won't judge my whole sex or peer group by my personal occasional lapses into idiocy.

If you must know, I'm 27 and female. This is the first time I've done anything even approaching this sort of thing (I've never even used a capture card to capture still shots before!) and I know I'm asking dumb questions. It's not because I'm unwilling to experiment, it's because I don't know where to begin experimenting sometimes, and because quite frankly, I've absorbed so much knowledge in the past few weeks that my brain feels ready to explode.

This site is extremely comprehensive, and I laud that. But I've got an entire 1 inch three ring binder filled with print-outs of "how to" guides, and sometimes I don't know which one to look at for the snippet of relevent information. I've been at this for two weeks, two different capture devices, two different operating system platforms (which is why the second capture device was required in the first place--Win2K didn't want to play nice with my ATI card, which proceded to work fine once I rebuilt in Win98.) I've downloaded 20 or 30 different applications that have been recommended at one time or another for some reason, and every day two or three new ones appear. I'm bouncing back and forth between two computers, one upon which I'm doing all my capture, editing, converting and burning stuff and the other one I'm online constantly checking this website for any data I need.

Experts are called experts for a reason. They've been through all the trial and error and know the subtleties that those of us who are new to the whole thing don't. We newbies would be foolish not to try to avail ourselves of your expertise and experience. I don't think anyone expects you to stop what you're doing to check things out for them--people just want to tap whatever knowledge is already rattling around in your brain.

Kristel

[speedy]

Memo to Kristel:

I'm sure you've found that the "experts" here frequently disagree, which to me suggests the advice isn't always that expert and is frequently colored by biased opinion. That is not to knock anyone, rather to point out your milage may vary even if you follow suggestions to the letter.

How a video "looks" is frequently more subjective than objective, so how one perceives what one sees and what suggestions if any one follows must be taken with a liberal amount of salt.

The best advice anyone can give you is EXPERIMENT and see what procedures work best on YOUR computer, DVD player, CD burner, source videos, etc..

While TMPGEnc can be a marvalious tool, it as yet don't have a help system nor has anyone put together more than a few how-to pages which is far short of the typical hundreds of pages such a product would typically get once there is a commerical release. So kick the tires and try various things and in no time you'll become an "expert" too.

[KSJ]

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On 2001-10-17 09:17:36, speedy wrote:
Memo to Kristel:

I'm sure you've found that the "experts" here frequently disagree, which to me suggests the advice isn't always that expert and is frequently colored by biased opinion. That is not to knock anyone, rather to point out your milage may vary even if you follow suggestions to the letter.

How a video "looks" is frequently more subjective than objective, so how one perceives what one sees and what suggestions if any one follows must be taken with a liberal amount of salt.

The best advice anyone can give you is EXPERIMENT and see what procedures work best on YOUR computer, DVD player, CD burner, source videos, etc..

While TMPGEnc can be a marvalious tool, it as yet don't have a help system nor has anyone put together more than a few how-to pages which is far short of the typical hundreds of pages such a product would typically get once there is a commerical release. So kick the tires and try various things and in no time you'll become an "expert" too.

</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

Thanks. I'm not even asking to become and expert. I'll happily settle for just getting one of the darned things to work.

Last night for the first time, I captured an entire hour-long show (minus a few minutes since I skipped past *some* of the commercials with my PVR's 30-second skip forward button, using the multi-segment file thing, which was great. And I figured out how to edit out the rest, which was even greater. Then I tried to do the frameserve thing into TMPGenc. I followed all the directions in the how to guide, moved the appropriate .dll files into the appropriate folders, double clicked on the "proxyon" icon in the AVIproxy folder, did everything I was supposed to, but when I tried to open the "video.vdr.avi" file in TMPGenc, I got an error that read "can not open or not supported." So I followed the directions again to turn "DirectShow Multimedia File Reader" to "higher priority, as it says to do if you encounter an error, and it *still* wouldn't open the video.vdr.avi file, so now I'm stuck again.

KSJ

[mpack]

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On 2001-10-16 15:24:48, georgia_dutchman wrote:
Since SVCD (& MPEG2) support interlaced, am I hurting the quality of the final SVCD video if I deinterlace the captured video before converting to SVCD? Thanks
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

That's a definite YES!

To elaborate... don't make any attempt to deinterlace the source video in VirtualDub or whatever. Don't using any smoothing or blending filters which disturb the interlacing artefacts - those little "interlace lines" are supposed to be there!

It is ok to use any temporal or smoothing filters which have an option for "field mode" or "interlace mode".

When you are ready to code with TMPGEnc, select source type: interlaced, encode mode: interlaced, source and dest aspect ratios: 4:3, *don't* turn on the TMPGEnc deinterlace filter. Video arrange method: full screen. There is an option "field order" (A or B) but I can't tell you which is the right one. A is right for me just now, but it depends on your capture card, and may even change from capture to capture. All you can do is try one, and if you get jerky video out, try the other one.

[KSJ]

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On 2001-10-17 00:01:13, anti-alias wrote:
KSJ -- Click setting, click "Advanced" tab. Should see

Video Source Type: Interlace
Field Order: Top Field First (field A) --or-- Bottom Field First (field B)

I can't say if this is causing your jittery video though ... lots of stuff can go wrong.
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

Thank you. I haven't had a chance to test this and see if it helps with the jerkiness of the high motion sequences, but it's a start. Once I get my little "can't open the frameserved file in TMPGenc" problem solved, I will give it a go.

HOWEVER, as for the shaky general picture, is there anyone who can point me in the right direction. I know it could be lots of problems with lots of potential solutions if I do nail down the problem, but I can't even begin this process until I know what to look for, and providing your solution for the jerkiness of the motion sequences it, it MAY be my last big issue in producing a decent quality SVCD. The rest of the stuff, like fixing the fact that I can't scan forward and back, indexing and adding chapters, is all gravy after that.

KSJ

[KoalaBear]

Kristel:

Thanks for the info. Like I said, those answers aren't relevant in any practical way, but they help me to understand your situation somewhat better.

The overall process can be divided into 6 steps:

1. Capture (asset creation)
2. Process (image enhancement, deinterlacing)
3. Edit (remove the commercials, transitions, fades, etc.)
4. Encode (generate compliant MPEG-1 or MPEG-2 file)
5. Author (create menus, combine programs, etc.)
6. Burn (write to CD or CD-RW)

The details of these steps differ primarily according to the capture format you choose. For example, if you capture directly to MPEG that decision will have ramifications in terms of what processing, editing and encoding options are available to you. It will also affect the nature of the difficulties you encounter when you hit a rough spot.

How are you capturing your video at present?

---

Georgia_Dutchman:

Ebaldino pointed out in another thread that current events have put us all in a tense mood lately, and he's right. Now that my tension has been safely checked at the door, maybe I can offer you some better advice.

In my opinion it always pays to deinterlace, especially at lower bitrates, for three reasons:

(1) MPEG-2 can handle interlaced files, but the mechanisms it uses to achieve this aren't particularly efficient. The encoder has to generate two motion vectors for each macroblock (one for each field) and the macroblocks themselves are scanned in an order that can't be as tightly compressed. This drains bits from the picture that would otherwise be spent coding motion.

(2) DVD players are capable of re-interlacing progressive sources for TV display, so by deinterlacing in advance you're effectively shifting that burden from software to hardware.

(3) If your original source happens to have originated on motion picture film, the deinterlacing method used on these sources (Inverse Telecine, or IVTC) can net you some handsome returns in picture quality.

The downside to deinterlacing is that it involves more careful capturing and processing. Whether such additional effort is worthwhile depends on the quality you expect versus the effort required to achieve it.

[jerome]

Kristel, you have only made a little mistake in the frameserve thing. change the name "video.vdr.avi" to "video.vdr" and it will work

Best Regards,
Jerome

[bdr43]

This could be the beginning of a beautiful relationship

I know this has nothing to do with the subject

[KSJ]

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On 2001-10-19 13:42:47, KoalaBear wrote:
Kristel:

Thanks for the info. Like I said, those answers aren't relevant in any practical way, but they help me to understand your situation somewhat better.

The overall process can be divided into 6 steps:

1. Capture (asset creation)
2. Process (image enhancement, deinterlacing)
3. Edit (remove the commercials, transitions, fades, etc.)
4. Encode (generate compliant MPEG-1 or MPEG-2 file)
5. Author (create menus, combine programs, etc.)
6. Burn (write to CD or CD-RW)

The details of these steps differ primarily according to the capture format you choose. For example, if you capture directly to MPEG that decision will have ramifications in terms of what processing, editing and encoding options are available to you. It will also affect the nature of the difficulties you encounter when you hit a rough spot.

How are you capturing your video at present?
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

Koala:

I replied to you via private message, since a lot of the details I provided aren't appropriate to this particular board but cover issues I've had capturing and authoring as well, so please let me know if you got the message.

Kristel

[KSJ]

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On 2001-10-19 14:01:12, jerome wrote:
Kristel, you have only made a little mistake in the frameserve thing. change the name "video.vdr.avi" to "video.vdr" and it will work

Best Regards,
Jerome

</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

Jerome:

The "how to" guide very specifically said to save as video.vdr.avi for frameserving. At any rate, ends up my problem was that where it was supposed to say "Frameclients Installed: AVIFiles" it said "none." I had missed a detail when running "Install Handler" (the detail being that I stupidly didn't *run* it at all, but interpreted the text in the window that came up as being instructions for steps I was supposed to manually perform) and therefore VDRemote and AVIfiles never got added to my registry, since I *couldn't* do that manually, or didn't know how, at any rate. Once I actually clicked on the window that contained the "instructions" and then hit "OK" it actually performed the task automatically and all was good.

See, it's those little details that leave you stumped.

KSJ



<font size=-1>[ This Message was edited by: KSJ on 2001-10-19 17:26:58 ]</font>