need help on a hybrid interlaced DVD (23.976 and 29.97)

[chilledinsanity]

Hey, I'm trying to do an encode where there's NTSC material mixed in with the film framerates. I've been experimenting with the different techniques and found inverse telecine gave the best quality, but was very choppy on the 29.97 sections. After some research, I found Decomb worked pretty well, but was still a tad choppy on the 29.97 sections compared to something like Smartbob, which went very smooth, but had noticeably less quality. Does anyone have any suggestions on what to do? Size isn't too much of an issue since I'll be burning to DVD-R although it would be nice if it wasn't too redundant.

Here's the command I put in my .avs file:

Telecide(order=1,guide=0)
Decimate(mode=1,threshold=50)

I tried guide=1 and 0, didn't seem to make much of a difference. I'm open to whatever, just so long as I can get it smooth and still look good.

[scharfis_brain]

I've made a script that reduces 29,97fps interlaced video to 23.976 fps progressive without jerkiness. but this script is very dumb. it doesn't check for telecines etc. it just reduces everything.

you can find this script here: http://home.arcor.de/scharfis_brain/60ito24p.html

[chilledinsanity]

Well hell, I'm finding no all-working solution. At this point I might be willing to sacrifice the 29.97fps to 23.796 since the majority of the content is a film framerate. I can't get everything to look right either way with decomb. At 29.97 fps, the 23.796 content looks like kind of jerky unless I tell it to blend the fields, but if I do that the normal 29.97 looks a bit jerky. If I don't blend the fields the reverse is true.


Scharfis brain, your solution definitely sounds intriguing, but on your webpage, I couldn't download the script. I wasn't sure if you included it in that post of yours in the other forum or not, I'm not too advanced with this stuff.

Out of curiousity, how do TV studios go about converting 23.976 fps content to 29.97 broadcast material?

[scharfis_brain]

Scharfis brain, your solution definitely sounds intriguing, but on your webpage, I couldn't download the script. I wasn't sure if you included it in that post of yours in the other forum or not, I'm not too advanced with this stuff.
oh, sorry I had and UPPERcase-mistake on my website. the script should now be downloadable.

Out of curiousity, how do TV studios go about converting 23.976 fps content to 29.97 broadcast material?

they do a thing called "telecine".
it is nothing else, than repeating the 1st frame twice and the second one 3 times.
I think, that Google will give you a lot of better explantations than mine.

[chilledinsanity]

Well I've decided I'm going to reduce everything to 23.976 one way or another. I've found out the best way to do this using Decomb on the individual sequences, but not together. I don't think your script would work on this since yours is designed for 60i and I'm not sure if Decomb does that. Here's what I've been doing:


If the section I'm working with is truly 29.97fps content, I put this in the .avs file and process it as a 29.97fps file:

Telecide(order=1,guide=0,blend=false)

Then, in Virtualdub, I tell it to change the source framerate to 23.976 and the conversion output to 23.976fps.



If I'm dealing with 23.976 content then I just run the inverse telecine operate through Gordian Knot:

Telecide(order=1,guide=1).Decimate()

Then it processes through Virtualdub.


The end solution is to join the clips together in the right places once I'm done and the whole thing will be at 23.976 and the 29.97 content will still go smoothly and have great visual quality. The only problem to this method is that it's a pain in the ass. If somebody knows of an easier way to automate this and still get the same results, please let me know. Thanks.

[manono]

Hi-

I think that Decimate(Mode=3) will do a better job, and certainly do it more quickly. You might also give SmartDecimate a try.

[chilledinsanity]

I tried decimate(mode=3), some people might not notice, but because I've been staring at the screen so much lately I some small jerkiness on the 29.97 content. Is there a special threshold it might work better at? Also pardon my ignorance, but how does Smartdecimate work?

[manono]

Hi-

If I'm not mistaken, VDub is performing something similar to a ConvertFPS(23.976) on the video portions (something you can do yourself in AviSynth). The result plays fairly smoothly, but is pretty blurred because of all the blended frames. Decomb's Mode=3 will have fewer blended frames, but plays slightly more jerky. And if you don't like Mode=3, then you won't like SmartDecimate. It's clear (no blended frames at all), but plays slightly more jerky again. You can read the doc for more information.

[chilledinsanity]

Actually I decided to cave in and use the mode=3 for encoding the full file, then go back in with the vdub conversion for the glaring scenes. It's not an ideal solution, but it's better than inverse telecine, which is what I was doing. Thanks for your help though.

[DDogg]

I generally leave my DV interlaced. Today I'm in a time bind and have a length/space constraint issue where I would like to encode some deinterlaced NTSC DV footage to Mpeg2 at 23.976 and then apply pulldown to the resulting mpg for the final framerate of 29.97 (without result being jerky). I've quickly researched and put together this script from various threads. It seems to work fairly well, although pans are still having a small problem with jerkiness. Any comments or tips for improvement in this script or general method?

Import("D:\convert60ito24p.avs")
avisource("D:\DVSource.avi").ConvertToYUY2( interlaced=true).ReInterpolate411()
jdl_UnfoldFieldsVertical(flip=true)
PeachSmoother(NoiseReduction=50, Stability=30, Spatial=200, NoiseLevel=3.5, BaseLine=2.5)
jdl_FoldFieldsVertical(flip=true)
DGBob(Order=0,mode=1).convert60ito24p(3,0)

[bilu]

Has anyone tried to use only the 60ito24p script on the complete hybrid movie? I've tried it on video parts and looked much better than Decomb mode=3. On the film parts it looks funny but doesn't stutter.

EDIT: Combining this with SmartDecimate would make a hell of a filter.

Bilu

[chilledinsanity]

I'm finding the conversion method via Virtualdub only works the best on pure NTSC content. On the "pseudo" NTSC/film content mode 3 works better. I wouldn't doubt the 60ito24fps content looks way smoother, but I haven't seen anything match the visual quality of decomb as of yet. I'm hardly a veteran though. Since the majority of the hybrid stuff I'm deinterlacing (The X Files DVD's) is film content with only small sections of NTSC, focusing on the 23.976 content first then the 29.97 content is my preference.

[scharfis_brain]

On the film parts it looks funny but doesn't stutter.
maybe the offset-parameter (the second parameter) could help in this case....