Need to telecine for dvd authoring?

[fortension]

OK, after spending a bunch of time figuring out how to capture and IVTC NTSC TV broadcasts, I got good results.

Now, when I want to take the mpg2 24 fps files into authoring programs, it gives me errors - not recognizable as NTSC in DVDit and converts it back to 30 fps in DVDLab.

Do they need to be telecined again for DVD? SVCD is perfectly happy with 24fps, so I'm not getting what's going on. Thanks for the impending insight.

[pijetro]

Why are you IVTCing your broadcasts?? They weren't telecined in the first place, so why would you inverse telecine them??
Many authouring softwares won't accept 23.976fps (I guess you found one). That's why pulldown.exe is run over the .m2v files to trick the authouring software that it's a 29.97fps.

[fortension]

The original recording was done on film, so it was telecined along the way for broadcast. It's not that unsual really.

Doesn't pulldown.exe actually change the real framerate - not just a trick? And thus waste bitrate?

OK, so anyone know authoring software that supports a 24fps video, hopefully with AC3? I seem to be having very bad luck with my program choices. I'm thinking SVCD seems like a pretty good idea for TV.

[fortension]

OK, after reading up on the topic tonight, I might be able to answer my own question. Pulldown.exe would work in changing the flag, allowing it to be seen as 29.97. It turns out DVDLab does it automatically, but my picture turned green. Still waiting to see if it shows up that way on the dvd. I'm still really learning to appreciate svcds.

[adam]

IVTC'ing your captures, assuming the source originated as film, is a very good idea. It increases quality dramatically.

The pulldown flag does not trick anything and it does not change the framerate. It instructs the dvd player to do a real time telecine as the movie plays. Almost all commercial DVDs are encoded like this because it is much more efficient and higher quality than hard telecining the video to 29.97fps.

All dvd authoring software should support 23.976fps with 3:2 pulldown. If your software doesn't than its not worth using. Green picture cannot possibly be caused by the framerate, there is something else wrong.

BTW, if you encoded at 23.976fps and didn't apply the pulldown when making SVCDs then your disk is non-compliant. It may play ok on your current dvd player but it won't play on most others.

[willie1]

I use TMPGenc to work with 23.97fps movies. Spruceup accepts these files no problem. It also allows ac3 audio which most basic authoring programs do not. You can convert them back to 29.97 fps in tmpgenc if you desire as well.

[pijetro]

I'm sorry, I shouldn't have said tricked. I'm thinking like my 3 year old. I've personally found success with IVTC when capturing blockbuster videos and capturing at a resolution of 640x480....

Are you capturing both fields?? IVTC works properly only when both fields are captured. BTW, you shouldn't have to deinterlace. You'll also notice after running pulldown.exe, the filesize doesn't change from your original 23.976fps filesize.

As far as converting back to 29.97fps with Tmpgenc, I would be carefull. I read on a previous post that it does a hard telecine, rather than setting flags. Correct me if I'm wrong.....

[fortension]

Thanks for the advice guys. Maestro and DVDit didn't let me import 23.976 video without using a pulldown flagger. I tried DoPulldown.exe, which seemed simple enough (from doom9). And yeah, file size was the same.

And I might as well throw in that AviSynth was the only program I got to IVTC decently (which does deinterlace as part of the process).

I may have to check out SpruceUp. I still haven't found a program I'm happy with. Does it apply a pulldown automatically? If it doesn't, would that make it potentially non-complient?

So then a DVD player will ignore the 29.97 flag if the output is set to a 480p output? Or does it get reconverted only with a HDTV?

And that's scary about my old svcds maybe not playing on future players...

[adam]

A compliant DVD authoring package should not accept 23.976fps input absent the pulldown flag. If anything does, than that's scary that the developers were that clueless. I don't know of any authoring programs which automatically apply the pulldown either. Just use pulldown yourself.

HDTV's support progressive 24fps playback but they don't require it. If you play a 23.976fps encoded DVD with pulldown flags on a regular dvd player, you will still get 29.97fps playback. Also remember, this is basically what's going to happen with ~95 of all commercial NTSC DVDs, since they are almost all encoded like this. In order to get progressive 24fps playback you have to play the DVD through a progressive scan DVD player, and basically yes these players just ignore the pulldown flag but they do line doubling to increase quality and prevent flicker.

If you are going to spend that much money on an HDTV than do yourself the favor and spring for a progressive scan player. It will definitely make a difference.

[willie1]

You can set TMPGenc to flag or hard tecline. I use the flag. DVD2AVI works well for IVTC. Select Force film under the video tab if your original source is DVD. Otherwise use AVIsynth.

[Quigonsean]

I just found I could cap in 23.97 with my capping software WinDVR. If I do this, the demux and run pulldown.exe, do I have to do anything to the audio. Lik it will be at 23.97fps like the vid, but after the 3/2 pulldown the vid displays at 29.97, do I have to convert the audio from 23.97 up to 29.97 to use with a 23.97 video that has 3/2 pulldown set ? Or should I keave the audio alone after demuxing. (I cap in mpeg2)

Thanks,
Sean

[adam]

When film is telecined from 24fps to 29.97fps the playback speed doesn't actually change. To increase the fps, new frames are just created every second, so the number of seconds is still the same. Basically whether you are dealing with 24fps or 29.97fps video, the audio is left unchanged.

Now, I don't see how you can cap at 24 fps if the source is being played at 29.97fps. The only way to cap analogue sources "at 24fps" would be to cap at 29.97fps and do a real time inverse telecine. It seems to me all you are doing is telling the software to randomly drop frames. Is the playback smooth? I would think it would look pretty bad. Someone please correct me if I'm wrong.

[fortension]

I found the flag in TMPGEnc. The frame rate should say 23.976 (29.97 internal) or some such. In the playing around with different templates, I must have left it at just plain 23.976.

I can't imagine a program would cap at 23.976 by way of doing a real time IVTC. It's intensive enough, and it requires multiple frames compared. Unless it's real quick and dirty...

[adam]

I didn't explain that very well. I didn't really mean all in real time. Basically, you cap to avi in virtualdub, and set it to frameserve to your encoder while running an IVTC filter. If the source has just been telecined through a standard 2:3 telecine pattern than an IVTC really doesn't require any extensive processing. All the filter has to do is decimate frames in the set pattern, it doesn't actually have to analyze any of the frames. Its practically real time but yes its very CPU extensive.