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yet another tc idiot


Bob

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I still haven't wrapped my head around the idea that, after all these years, the US hasn't just changed things to a solid 30fps instead of all this 29.97 (and 59.94 and drop-frame and non-drop-frame) BS brought about by a shitty work-around when it thought about going from B&W to color TV broadcasting... in 1953. The Europeans have it down with 25fps and don't have to do all these calculations with their attendant possibilities for error.

The thing is (or at least it used to be) that those frame rates aren't just numbers people decided, but are based on the electrical grid frequencies. If you wanted to come up with a system like that in america, almost every AC device you own would end up as garbage.

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It also means that European films shot at 25fps have to be slowed down by the same amount to be shown here.

No, actually we can transfer 25fps films at 24.96 (or a similar fractional speed) to 29.97 HD or SD video, and it works fine. Generally, only European TV productions have this issue. Those transfer over just fine -- only a .1% difference. 4% is huge by comparison.

24fps films are transferred in America at 23.976 for the same reason. I think it only affects the run time of a 2-hour movie by maybe 3 or 4 seconds (total), so it's not a big deal in the grand scheme of things. Audio post has to be aware of it when preparing or outputting reels or files, but it's something that's been dealt with so long, most facilities are already prepared for it.

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  • 1 month later...

Hey all,

I am dealing with an almost identical situation on a reality show, except the camera is set to 1080i, 59.94i (I apologize if I got that label wrong, but that's what the camera guys are telling me). Oh, and they are doing DROP FRAME. Under the TC menu for the HDX900, there is an option that says, "TC Display Options (with 24F and 30F as the only choices)." According to the manual, this just means that the display will count to the 24th frame or the 30th frame. This doesn't sound like it actually changes the frame rate. I'm trying to cross jam my 788T and Denecke sync boxes. My audio recorder (the master clock) is set to 29.97DF, and the SB-3 is set to 29.97DF (for the record, that's option 9 on the Denecke rotary dial). Am I doing this wrong? Post is complaining of major TC drift, and I am really getting confused by the camera.

There is also another menu that says "TC VIDEO SYNCRO." Apparently this will delay or forward the TC signal according to the selected video settings. Do I need to make adjustments here, or is this nothing to worry about? I really don't understand how this part works, so any advice is helpful.

Thanks, all. Also, in case anyone else has to use this Godforsaken model, here's the link for the user's manual (TC menu is discussed on page 130):

ftp://ftp.panasonic.com/pub/panasonic/drivers/PBTS/manuals/OM_AJ-HDX900.pdf

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Yes, the Panasonics can use 29.97DF timecode. The 59.94 is just the field rate for normal 1080i (very standard for network and cable delivery). Just roll sound at 29.97DF and set TC slate to 29.97DF. Works fine. [Do a workflow test if possible to make sure all is well!]

I'm puzzled that so many reality shows shoot in DF, because it's really not necessary. DF is only needed for delivery. All they have to do is, shoot the show in Non-Drop, edit the whole show in Non-Drop, then make the final master (tape or files) with DF code. This is done every single day on every American sitcom and dramatic show I know of. I have no idea why reality people think their shows are "different" and need to be done with Drop Frame code. I think it's the F.I.S. Factor: "Fear, Ignorance, and Stupidity." That's an unbeatable combo.

The couple of times I've done reality projects, I was flabbergasted that they were doing Drop Frame, but when they insisted this is how they'd always done it, I said, "no problem -- it's just this little chromium switch, right here." Give the client what they want, even if it's stupid.

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The Panasonic records at 29.97 ( It does internal FRAMERATE pull down conversions ). When it's running at 23.98 fps, the HDX900 is actually a 59.94 device and uses 29.97 fps timecode.

I would suspect that they are Not using DF for aquisition. I have had a lot of experience in post with these cameras. They are fairly notorious for speed issues and drift in a dual system or multicamera shoot. I insist upon tri sync genlock on all the cameras using an audio recorder as master. it has worked flawlessly.

BTW.. I work primarily on documentary ( reality ) projects and we never shoot DF.

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What does the 788T Timecode Jam menu say for the incoming Frame Rate when you connect it to the HDX-900?

It will tell you if the camera is in drop or non-drop. Also, there should be a "DF" in the upper left corner of the TC/Audio meter LCD on the camera if it is in Drop Frame.

Done it both ways, no issues as long as you match up.

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I know some of the Panasonics run 720p@59.94 progressive scan, which is why it isn't called 59.94i; since there are no fields. Some HD television channels will even show the 720p at this double rate, especially for things like sports it is quite nice.

I've no idea what the camera will produce as timecode at those rates. I guess it creates a half rate timecode, for compatibility with older workflows. As an engineer it irks me that a camera is lying in its timecode about the actual speed it is running. If the camera designers (and timecode generator designers) ever change their mind, Boom Recorder will take in any speed you will throw at it.

Now films are being shot at double (48) and tripple (72) speeds which will help a lot with the quality of 3D productions. So new frame rates will happen more and more often.

At an IBC a few years ago I've seen a demo with 1080p@300, which is quite amazing how much difference it makes in sharpness with fast movements.

Nothing to do with speed, but a few months ago at the IBC I had the pleasure to enjoy Hugo in 3D on a new prototype laser projector, which has a much higher light output in 3D (including wearing the glasses), on par with high quality 2D theatres. I hope next year they will show the hobbit at its intended double speed on such a projector.

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I'd like to comment on how informative and helpful this thread is (and jwsound) in dealing with issues like Time Code. Some producers are aware of how the sound dept. keeps on top of these things and how we take initiative to solve problems. Others have no clue and are usually first to start blaming--that's never going to go away! It's frustrating yes, but I don't think that's ever going to stop us from stepping up and "handling it", and maybe charging a little more for out expertise in the process.

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Some HD television channels will even show the 720p at this double rate, especially for things like sports it is quite nice. I've no idea what the camera will produce as timecode at those rates. I guess it creates a half rate timecode, for compatibility with older workflows.

No, I have worked on 720P 59.94 projects for FOX TV here in America (many promos), and while editing in this mode is "clunky" at best, the timecode is straight, ordinary 59.94. Timecode has no fields per se, although some edit controllers (like the TLC we used to use in telecine) did show ".0" and ".1" for even/odd fields in jog mode. Field jog mode goes away with progressive -- it simply goes to the next frame.

I have been told that SMPTE does have a working committee right now that's trying to hash out new kinds of timecode for 48fps, 72fps, and even higher frame rates, for those productions crazy enough to shoot that way. Given that they have yet to finalize monitor standards for HD (!!!) -- what the industry is working with is a "temporary" recommended practice -- I don't expect this to happen soon.

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  • 2 years later...

As for why do reality shows sometimes use DF for acquisition?

My suspicion is that the order rolls downstream from the almighty spec sheet given to the production company by the network. The producers don't always understand the tech stuff and just hand it to the DP or camera op of the day and say "make it so". It's then up to the DP to interpret and after that becomes scripture for the rest of the series.

A secondary possibility of that they want DF in the field so that logging and transcripts are accurate to real time. On certain shows this could be important.

 

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Just a quick note about European fps part of this thread. Not everything is shot at 25 fps here. Only stuff for TV is. Everything for cinematic release is shot at 24 fps. Although I have had several made-for-cinema jobs now that were shooting at 25 fps. I think they find it easier to go from 25 to 24 than the other way. Also, apparently the DCP doesn't really care anymore.

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Broadcasters use drop frame so that their pulled down frame rate (29.97 or 23.976) always show the correct time of day or the correct length of the program.

I think shooting in drop-frame is incredibly stupid and unnecessary unless it's for news and the piece is going to go straight to air. If it's a documentary or a reality show or (god forbid) a scripted show, shoot it in non-drop and then let the editor output the final edited master to drop-frame for final delivery. It's trivial to do, and figuring out the timing is not a problem (you gain 3 seconds per hour). 

On the other hand: if the client demands drop-frame, and they sign the checks, I give them what they want.

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  • 2 weeks later...

I believe post facilities that are setup for broadcast programming are nondrop throughout the facility, therefore want to receive nondrop production timecode.

Just to sound like The Senator for a moment, this is a big "it depends" caveat. I have actually seen reality shows that are absolutely drop-frame all the way from initial production to offline to final mix to air. I don't agree with this approach, but in some cases these are legacy people working on old shows who are reluctant to change a workflow that functions for them. As long as the sound department and the camera department are on the same page, it shouldn't be a problem.

I personally think it makes much more sense to shoot and mix the entire show in NDF 23.98 or 29.97, then convert to DF at the very end for delivery. The post producer just has to be aware you have to hit a certain runtime 1.5 seconds earlier in order to make the exact program length required by the cable network (assuming a 30-minute show). People get it in their heads that the runtime could be 3 seconds wrong per hour, but it's very fixable when the editor knows exactly how long each segment has to be and how they have to add up. 

I've also dealt with productions that routinely mixed 23.98 and 29.97 material; American Idol is one of them, where the bio packages they shoot on the contestants are often at 23.98, but the show itself is 29.97. Plus it's 720P because it's FOX (not even 1080). There's a whole mess of standards out there.

Edited by Marc Wielage
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