progressive pal to ntsc conversion

[lj01]

Hi - for all those who helped me with my vhs capture problem last week - thanks, everything worked out great - and unfortunately i'm back with another. I've been trying to work on this but could maybe use some suggestions.

My next project involves converting a progressive PAL source to NTSC. I know the preferred option would be to have a DVD player that does both and not convert at all but for this particular project it's my preference to do the PAL>NTSC.

So, I've tried numerous methods but nothing seems to come out exactly right. The source is progressive PAL AVI (720x544, 25 FPS). My method thus far has been this:

a) Use AVS2DVD to split the AVI into mpeg-2 streams, outputting still as PAL but changing the size to 720x480
b) Use dgpulldown on the resulting m2v file to then change the framerate from 25 to 29.97

The result of (a) is interlaced, and obviously so is (b) and I'm assuming that there's no other way to do this than to have the end result interlaced (other than using a method which just copies frames). Is there something else I should be doing, and/or should I be IVTC from 25 FPS to 23.976 and then running dgpulldown? I have tried to IVTC in Vdub but for some reason that takes the framerate down to 20 FPS (I'm not sure if that fact might be helpful in deciphering what I'm doing wrong?)

Anyway, if someone has any ideas or new methods I could try, I'm all ears. The help I got last week from this board helped restore my sanity (thanks especially sanlyn & manano). I'm sorry to go back to the well so soon after getting bailed out by you guys last week but this is obviously not my area of expertise and I'm very interested in hearing suggestions - thanks!

[jagabo]

a) Use AVS2DVD to split the AVI into mpeg-2 streams, outputting still as PAL but changing the size to 720x480
b) Use dgpulldown on the resulting m2v file to then change the framerate from 25 to 29.97

The result of (a) is interlaced, and obviously so is (b) and I'm assuming that there's no other way to do this than to have the end result interlaced (other than using a method which just copies frames).

In that sense, all DVDs are interlaced. Your video is encoded with progressive frames. The pulldown flags added by dgpulldown tell the DVD player how to produce 59.94 field per second interlaced video from those progressive frames. The same is true for regular 3:2 pulldown flags on any "progressive" DVD.

The other way you could do this is to slow the 25 fps video down to 23.976 fps and use regular 3:2 pulldown flags. But then you'd also have to slow the audio to match.

[lj01]

Thanks jagabo - you were also very helpful with my vhs dilemma last week.

how would i slow the video down? i'm thinking that might be the answer but everything i've tried in order to do that hasn't worked (i tried IVTC in vdub but for some odd reason it slowed it down to 20).

thanks again.

[jagabo]

how would i slow the video down?

In VirtualDub select Video -> Frame Rate... Then in the top section (Source Rate Adjustment) tick the "Change Frame Rate to (fps)" line and type in 25. If you know AviSynth: AssumeFPS(25).

[manono]

how would i slow the video down? i'm thinking that might be the answer

It's not the answer. The final DVD output will also be interlaced, just 23.976->29.97fps interlaced rather than what you have now, 25->29.97fps interlaced.

Do you have DGIndex? If so open a VOB from the PAL to NTSC DVD AVSToDVD made and run the Preview. Under 'Frame Type' does it say 'Progressive'?

The result of (a) is interlaced, and obviously so is (b)

It's supposed to be. But, if done right the video itself should have been encoded as progressive.

I'm not saying you shouldn't slow the audio and video down to film speed and encode for 23.976fps with 3:2 pulldown. That's what I do myself. I'm only saying you've already made a progressively encoded DVD (I think).

[lj01]

thanks for the info, you're correct, it's progressive. I guess the problem isn't necessarily that it's interlaced, it's just that the motion is not as fluid as i would like - which actually may go back to the source. Are there any filters that would help out? MCTD? I think I need more of a motion-smoother than anything else, I'm just not sure how to go about doing it. Thanks again for staying patient with me and for any help.

[TB Player]

This may not be what you're wanting to do, but I just re-encode the video with something like TMPGEnc or Adobe Recode.

[jagabo]

thanks for the info, you're correct, it's progressive. I guess the problem isn't necessarily that it's interlaced, it's just that the motion is not as fluid as i would like

3:2:3:2:2 pulldown (what you're doing with your PAL/NTSC pulldown) isn't noticeably less smooth than the regular 3:2 pulldown.

which actually may go back to the source. Are there any filters that would help out? MCTD?

MCTD is a denoiser. What might help are the motion interpolation filters based on MvTools. You can insert missing frames, replace duplicate frames (where a prior frame was duplicated to make up for a missing frame), etc. Here's a thread which discusses some of the functions:

https://forum.videohelp.com/threads/352741-Frame-interpolation

There is an automated variation that can detect when a duplicate frame has been inserted and replace the second duplicate with a motion interpolated frame.

A sample of the source that shows your problem would be helpful. You might have blended fields or some other problem.

[lj01]

Thanks jagabo, i really appreciate your helping me out - here's a short sample (this is the initial file) but i think it gives a decent look at the issue - it just doesn't seem to be fluid. I think that if there's some way I can smooth this out (and I'm not sure if that's even possible) then I think the final product will be fine.

if there's anything i can do - i'm all for it - thanks again!

[manono]

It's got duplicate frames, missing frames, and blended frames. As you said, it plays jerky. It's nothing to do with the DVD you made and making a 23.976fps one won't help at all. If it were I, I'd delete it and waste no more time with it. Maybe look for a better source.

[lj01]

bummer - not the answer i was hoping for, but an honest assessment, thanks. but, as there is no other source for now, if anyone has any suggestions or possible patch-fixes that might smooth it over just a little, do feel free to let me know. thanks again.

[jagabo]

I agree, blended frames are the problem. I suspect it was originally interlaced NTSC, converted to interlaced PAL with blended fields, then made progressive by blurring the two fields together (ie blend deinterlace). It's going to be hard to fix that.

[lj01]

hard...or impossible? I'm pretty sure that's the case that underneath it all this is interlaced NTSC which was converted to PAL. So, if I were to somehow unblend the blended frames then I would be back to interlaced NTSC maybe and then not have to do the conversion? But, I'm suspecting from the last couple of responses that "unblending" is not a typical function. though, if anyone has a script i can run it through - even if it just slightly improves it - i would still be interested. thanks again for taking a look and for your assessments.

[manono]

So, if I were to somehow unblend the blended frames then I would be back to interlaced NTSC maybe and then not have to do the conversion?

You'd be back to a field-blended PAL video. Then it could maybe be unblended and brought back to its NTSC source. It was the blend deinterlacing that ruined it (further than the original field-blend conversion from NTSC). I, for one, don't know how to unblend something like that. Others might be able to. If not jagabo or someone else here, maybe someone in the AviSynth Forum at Doom9.

[jagabo]

There are some unblending filters that work for some types of blends but I don't think there's anything that can deal with this type of blending.

[jman98]

My next project involves converting a progressive PAL source to NTSC. I know the preferred option would be to have a DVD player that does both and not convert at all but for this particular project it's my preference to do the PAL>NTSC.

When we advise people to just "buy a converting DVD player" we're not just wasting our time. This thread illustrates exactly why we discourage PAL<->NTSC conversions.

[lj01]

Thanks everyone for chiming in. In the end, there's nothing I can do to smooth it over, I take it?

[jagabo]

Thanks everyone for chiming in. In the end, there's nothing I can do to smooth it over, I take it?

There may be someone in the world who knows a way to handle it. But I don't.