Deinterlace without skippy playback?

[Kb_cruncher]

I have a NTSC Interlaced stream that i want to deinterlace,My problem is that every method i use gives me skippy play back due to frames being duplicated.

The stream has two interlaced frames followed by three non-interlaced(2,3,2,3,2,3......)

So far i have tried Decomb(telecide,FieldDeinterlace),ivtc2.2,TomsMoComp,SmoothDeinterlace.

TomsMoComp(1,9,1)seems to give the least amount of skipping.

Is there a way to deinterlace without intoducting any skipping at all?

[Kb_cruncher]

It seems i have answered my own dilema yet again.

dvd2avi jugded it as pure ntsc interlace 29.97fps(if i use forcefilm,interlacing is gone but very skippy,jerky playback),same results with IVTC2.2.But(and heres where i get totally confused)if i use GreedyHMA(1,0,4,0,0,0,0,0)i get Absolutly perfect result @23.976fps.

So it is 3:2 pulldown(film)afterall:confused:

[Richard Berg]

Did you use Decimate when trying Decomb?

[manono]

Hi-

The stream has two interlaced frames followed by three non-interlaced(2,3,2,3,2,3......)

So it is 3:2 pulldown(film)after all

The former was proof for the latter. And based on what you've said, you never tried Richard Berg's obvious solution. Don't rely on what DVD2AVI tells you.

[Kb_cruncher]

Yes i did try Telecide(guide=1).Decimate(cycle=5) but the output is very jerky(not so with greedyHMA).

I didn't rely on dvd2avi as i also tried IVTC2.2 for 3:2 pulldown too with the output being as jerky as forcefilm and Decomb(as above).

GreedyHMA was the only 3:2 pulldown method that gave smooth playback.

[slk001]

You neglected to tell us where your original stream came from. If it is a capture off of a NTSC television, then your video will be true 29.97 interlaced. If it was from a NTSC DVD, then this will most likely be from a telecined film.

My understanding of the way that DVD2AVI works to determine the source type, is that it looks for the 2:3 pulldown flags. If it finds them, then it will display the source as film. If it doesn't, then the source will be displayed as interlaced.

I capture NTSC laserdisks, which are true interlaced objects to DVD2AVI (because they are true interlaced objects), so I always use NONE in FIELD OPERATION block. I then use the following in my frameserving .AVS script:

IVTC(30,50,70)

This command violates the recommendation by the programmer, but these settings were the only ones that I found that would reliably deinterlace my captures (the caps are 24fps cartoons). The only cartoon that gave me problems was one that was blended prior to the telecining process (the problems were due to the blending, and could not have been fixed by the filter).

I also apply IVTC to a single CBR pass (no multiple passes) at the same bitrate and same GOP structure as my captures (I cap at 9.5Mbps using a low delay GOP structure of IPPP). This leaves me with a high bitrate, true FILM video stream that I now re-encode to a lower VBR DVD-complient stream (usually about 4.5Mbps AVG). This method has worked well for me - in fact, well beyond my wildest dreams.

[Kb_cruncher]

My source is ntscDVD.Most of my experience is with PAL,very few NTSC.I never have problems with pal and DVD2AVI's ForceFilm has worked fine for all the NTSC DVD's i have done so far,up until now.

The source is heavily interlaced,mainly in motion scenes.

Here's a rundown of what i have tried so far and there results.

DVD2AVI-force film enabled--Still interlaced in places with very skippy/jerky playback

IVTC(32,8,15)--No interlacing,but choppy playback,i get about 1sec motion then a very definate split second HALT...motion,halt,motion halt...

Telecide(guide=1).Decimate(cycle=5)--same as IVTC but more frequent.

TomsMoComp(1,9,1)--no interlacing,only slightly jerky.(best result so far and at 29.97fps).

GreedyHMA(1,0,4,0,0,0,0,0)No interlacing,near perfect,very slight skipping,proberbly wouldn't notice if you weren't looking.

GreedyHMA(1,0,1,0,0,0,0,0) for 29.97 fps output.in a word PERFECT,very smooth,no skipping/jerky playback)

The last result seems to contradict my first assumtion and the general opinion that this is film source and should be IVTC'd,leaving me more than a little perplexed:confused:

I will do some test encodes(xsvcd,full res)with both the GreedyHMA params and see how they playback on my dvd player.

I don't think its a coincidence that the two filters that gave the best results where both ported from DScaler.Many thanks to trbarry for some great filters.

[JohnMK]

Unless we're missing something, this appears to something worth neuron2's looking into. I might suggest you find a representative portion of the VOB, and do your best to split off a very SMALL section of it using VOBSplitter (I think that's the program's name). I might make it available at my web site if you don't have one. Please, no more than 10 MB.

Very perplexing.

[trbarry]

Kb_cruncher -

Thanks for the compliment on my filters.

But if you seem to get the smoothest output at 29.97 frames maybe you also might try Decomb without decimate. Sometimes the pattern of interlaced vs progressive frames does not indicate the pattern of repeated frames that would be removed with Decimate or the GreedyHMA decimate options > 2.

Just curious.

- Tom

[Guest]

If he has low frame rate animation, where each frame is repeated two or three times, then using mode=0 on Decimate will cause the described effect. If it truly is pure 3:2 material, that is the only explanation I know of for consistent jerkiness from Decomb.

[Kb_cruncher]

Well,some of what have said so far can go in the trash.it seems i have found the source of the problem.

I was using MPEG2DEC3-beta6 pp-mod @ cpu=4 in my script.When i changed to the non-mod MPEG2DEC playback is fine with 3:2 pulldown,but still only with GreedyHMA(1,0,4(5),0,0,0,0,0).All other pulldown methods i still get skipping.

I have also been getting errors with AVI playback until recently.I have found that FFDSHOW was the problem,which also impacted on my mpeg playback too(slow to start,freezing).As soon as i uninstalled it and went back to using default decoders everything returned to normal.I was using Sep23/2002 build.

I guess i should post some bug reports.

I will cut a piece of vob and upload it to my webspace(approx 6-8 mb)when i get some time in the next couple of days.it will be interesing to see what you think.

P.S playback on my DVDPlayer was quite jerky when i use MPEG2DEC3 pp-mod too.

[Marc FD]

for PP with MPEG2Dec3 on interlaced sources, ALWAYS use iPP=true, or it'll blend combing. using the field-based PP gives me very good results with Decomb, because sometimes some "good" fields are really blocky, and the deblocking fixes that pretty well. that's what i've noticed so far.

[Kb_cruncher]

thanks for the tip marc FD,i will give it a try.

For anyone thats interested here is a link to a test vob(7.33mb)

http://homepages.paradise.net.nz/gazzanz/test.vob

please take it easy as i only have 100mb D/L a month:)

[Kb_cruncher]

I have tested MPEC2DEC3 with iPP=true and the results are still the same.

I think this is a perticularly difficult source,some feedback on the test vob would be good to see if the problem can be duplicated on another system.

Anyway,all is fine and dandy using standard MPEG2DEC.

Thanks for everyones input and suggestions.

[Marc FD]

oups.. maybe you need to use blend=true too.
it's false by default, and if you set it true, the result is the same than a regular MPGE2Dec.. (bitwise)