Add pulldown to 23.98

[Guy]

looks like it’s coming:

At NAB 2005, AJA Video has announced that all KONA and Io products will support Apple

[David Massachi]

Does this mean it currently has no official 23.98 compatibility. When I play a 23.98 DV timeline I can see it on the outputs of the Io. Maybe it doesn’t have real 2:3 pulldown. I think it must have some frame rate/pulldown conversion because it’s playing back at what seems to be normal speed on an NTSC monitor (60i).

What are the current capabilities of playing back 23.98 DV using the Io?

massachi

[Steve Covello]

You actually ARE seeing it in 29.97, since FCP (not AJA) adds its own pulldown in realtime to the 23.98 timeline. This would be the only way you could see picture on a regular NTSC monitor. There are NO crt monitors that actually display 23.98 — they double the fields and play it back at 48 interlace (referred to as 23.98 Psf). If you goto the User Preferences (might actually be in System Preferences – can’t remember) there is a tab for Playback, within which are several options for what “brand” of pulldown cadence you wish to see on playback.

And BTW, are you working in 23.98 because you are doing a film out? Otherwise, there isn’t really much of a reason to capture/edit at 23.98. It’s not like you can output DV at 23.98 — ain’t no such animal. Just curious.

steve covello
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[Steve Covello]

You actually ARE seeing it in 29.97, since FCP (not AJA) adds its own pulldown in realtime to the 23.98 timeline. This would be the only way you could see picture on a regular NTSC monitor. There are NO crt monitors that actually display 23.98 — they double the fields and play it back at 48 interlace (referred to as 23.98 Psf). If you goto the User Preferences (might actually be in System Preferences – can’t remember) there is a tab for Playback, within which are several options for what “brand” of pulldown cadence you wish to see on playback.

And BTW, are you working in 23.98 because you are doing a film out? Otherwise, there isn’t really much of a reason to capture/edit at 23.98. It’s not like you can output DV at 23.98 — ain’t no such animal. Just curious.

steve covello
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[David Massachi]

I will probably make a 23.98 DVD when completed. I have a lot of 24PA footage, plus a lot of archival footage that originated on film.

The problem comes in with the archival footage that is super8 (and not transferred with telecine 2:3 pulldown) and regular 29.97i footage.

I may go with cutting it all in a 23.98 timeline, and using Nattress filters to make the 29.97 into 23.98, but that remains to be seen.

I did some preliminary testing of outputting the DV footage to digibeta via the Io. The pulldown cadence seems correct on the tape (2:3:2:3). But I had some problems with the outputting. The recording would unexpectedly stop during the layoff. I didn’t have time to investigate the problem very much, but I did see it happen on all 3 flavors of pulldown.

I’m not sure this is related to the on-the-fly pulldown or not. I’ll have to test further.

Thanks for you help.

massachi

[Steve Covello]

As far as I know, no matter what your delivery format — DVD, DVCam, DB, etc. — there is no such thing as a 23.98p NTSC output. No regular TV monitor can play it (not even $40,000 telecine CRT’s), and no deck will record or play it (see note below). There are some high-end DVD decks (that no significant number of people own) that do some fancy conversions, but I would be interested to hear what your ultimate delivery purpose would be. See below:

https://forums.audioholics.com/forums/archive/index.php/t-4575.html

(note: even though DVX-100 says that it is a 24p DV camera, it is actually acquiring at 24, but recording with pulldown to DV tape for NTSC compatibility. It does it in either 24pa (Panasonic’s Advance), or conventional pulldown. Sorry if you knew that already, but there could be some newcomers here…))

I would be psyched to learn that there is some new 24fps DVD delivery spec, so bust me up if I’m wrong here. I know that the only “format neutral” playback system is computers since they display in RGB/progressive at 75hz and higher refresh rates. We have sent out PAL dvds to north american clients with a note that the DVD can only be viewed on a computer or a PAL compatible TV playback/display system.

As to why your recording had stopped on output, it might’ve had to do with FCP being overwhelmed with trying to output realtime pulldown cadence and maintain the dataflow to output uncompressed to DB. You could take your 23.98 sequence and copy/paste it into a new 29.97 sequence and FCP will add the pulldown as needed. You will likely need to render it for output.

If you are outputting to DB, you might as well be working in 29.97 all the way through your capture/editing process. The way you are working now, you are merely substituting one form of pulldown (that which is native to the recorded footage on your source material) for another form (what FCP adds to fulfill an NTSC output).

steve covello
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[David Massachi]

It’s my understanding that most “hollywood” dvds are actually encoded with 23.98 video and “flagged” so that dvd players know when to add pulldown when necessary. I’ve heard this from several sources, and it makes sense to me. Making a dvd from a 23.98 fps movie uses 20% less disc space than 29.97, thereby allowing you to have higher bit-rate/better compression, and thus a better quality dvd movie burn.

Can anyone else confirm this?

When I was outputting to digibeta, I was doing it from a 23.98 DV timeline. The Io will output DV just like Uncompressed 8-bit, through all of its output connectors. So it doesn’t have a super-high data rate to deal with on output. But I do think that it has something to do with the on-the-fly introduction of pulldown. Maybe it’s too taxing for the system to do consistently for an extended period of time. And another maybe: maybe that’s what AJA means when they say the newest driver they’re releasing in May will be more 23.98-friendly so this can be done consistently.

Cut and pasting the 23.98 clips into a 29.97 timeline doesn’t add correct 2:3 pulldown. It does some weird interpolation of fields/frames, but it is definitely NOT 2:3 pulldown. That’s why I was thinking to use Nattress G Film filters, if I decided to cut in 29.97. After reading the instruction manual for the G Film filters, I think I might go with cutting in 23.98 timeline and using filters to convert my non-film 29.97 clips to 23.98. I’m still on the fence about this, but I guess at some point I’ll just decide and go with it. Probably after some more visual testing, and after I resolve my outputting problem(s).

massachi

[Steve Covello]

I’ll check into that holywood DVD format thing myself too. Thx.

As to the weird pulldown in FCP, you can choose which cadance of pulldown you want in the User settings under the Playback tab — or in System settings — one or the other, I forget.

steve covello
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[Steve Covello]

Well bite my tongue – you were right about the 24 fps thing — that is, that you could encode a 24 fps file into mpeg2 and the encoder will add the pulldown. The question I have is whether you can trust the majority of DVD players to be able to detect the pulldown correctly and display it in a way that is fundamentally aesthetically better than if you had done the process in 29.97. I guess if you are on the borderline with your program length and the top end of your DVD data, then going to 24 fps for the sake of quality makes sense.

Did you do any tests to arrive at this conclusion?

steve covello
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[David Massachi]

Even with the Pulldown Pattern set to 2:3:2:3, it still doesn’t render with 2:3 pulldown (here, I’m talkinga about 23.98 clips cut into a 29.97 timeline). I thought that setting was for playback only, not rendering. In the Playback Control tab of System Settings, it says that Video Quality and Pulldown Pattern are dependent on system performance. So I’ve always thought that those setting were about playback capabilities, and not rendering capabilities.

Do you think my system specs are not up to snuff, even with DV footage? If so, why isn’t it telling me it dropped a frame on output? It simply stops outputting and doesn’t give me any error message.

My system:

Dual G4 1.42 GHz
1GB RAM
OS 10.3.4
FCP 4.5
QT Pro 6.5.2
Compressor 1.2.1
Xserve RAID
RAID Admin 1.3.3
RAID Firmware version 1.3.1-1.2.4
AJA Io with Driver v1.2 and Firmware Update v21-24

massachi