Graeme ? on Broadcast Deliverables

[Michael Schrengohst]

Your edits will be spot-on when going 24p to 60i, since you aren't changing anything, just adding a field cadence.


By the edits being off, I mean that the timecodes can be a field off once you convert from 23.98 Non-drop frame timecode to 29.97 drop-frame timecode. Once you start skipping 29.97 timecodes, the 3:2 pulldown cadence doesn't line up anymore. i.e. if there were no drop-frame, the pulldown cadence would start on a second (and zero frames) and end right on a second (and zero frames).

So some 60i frames will have fields from two different 24p frames. You can't have that, since it won't cut perfectly from program to commercial (or other non-program). And the broadcaster can legally not pay the production for this. The onus is then on the post production facility to make the master properly, otherwise the production company will get tired of their mistakes and take their business elsewhere. So basically, the post facility would just make the master correctly.

There are be different workarounds for this problem. If you are packaging the show in a linear bay anyways (yes, linear), it can deal with the fields being off issue (and linear bays are good at packaging). *Not many facilities have a HD linear bay (let alone a linear bay). Another solution would be to package the show in the online system; you'd presumably need to nest the 23.98NDF program in a 59.97DF timeline. Or if for some reason that isn't supported, you can print to tape as 23.98, capture back from tape as 59.97 (Sony HDCAM and HDCAM SR decks add pulldown on the fly if you have the pulldown board installed), package the show, and make your master from there.

It's a little more convenient to online into a 59.97DF timeline to begin with. In this situation, pulldown in Redcine (or some sort of VTR) would be a convenience. *This is sometimes not feasible (i.e. you have a lot of effects work; cadence detection would get annoying) so you might want to put up with the 23.98NDF --> 59.97DF step.

(This stuff is really confusing, and I could be wrong here.)

2- See this old thread... (around pages 1-3)
http://www.reduser.net/forum/showthread.php?t=281&page=3

Have you ever tried it? You are getting all worked up on some theory in your head? We have delivered some spots and a 30 min local show - all shot and edited 23.976 and then output to HDCAM at 1080 60i....
we had no issues. Maybe National networks are more picky but I doubt it. It seems the higher you move up the chain the less time they have to check everything. And besides - it all goes from tape to MPEG servers for the most part anyway. In future I would think file based transfers will rule and those silly tape decks can go away.

 

[GlennChan]

I know that for the show "I do let's eat", it has to be packaged in 59.97 because they want the 60i versus 24p look (i.e. the show has segments in 24p, and in 60i). This is a different situation, but 3:2 pulldown from the deck (or Redcine) would definitely be an asset there.

PBS requires its shows to have accurate timings.

It may be that not all broadcasters are as... demanding... as PBS. It takes work to get that one frame right. But the post house has to do it.

2- Higher up in the food chain, they definitely spend a lot of time checking things. Shows get sent to another company for QC reports (this costs something like $800/hr), and the broadcaster does their own QC. The post house also does their own QC.

 

[Stuart English]

Pull down

Pull down

Well if it really is drop frame that causes the problem, then best shoot 23.98 or 59.94 drop frame in the camera.......

 

[GlennChan]

Isn't 23.98p timecode always non-drop? (In any case, I don't think 23.98 "DF" wouldn't really solve the problem.)

i.e. one frame of 23.98 lasts 5/4 times the length of a 29.97 frame. If you drop the same number of frames, you've dropped a much longer amount of timecode time.

2- Not adding pulldown is not really that big a deal for making 60i deliverables. At the worst, you need another step or two dealing with it.

And sometimes companies will have a linear bay to do all their packaging (since it's more efficient that way)... although not necessarily a HD linear bay. If you have a linear bay, it's just an annoyance.

2b- The big reason to add pulldown is when you need to preserve 60i and 24p look, or need to mix a lot of formats.

 

[tj williams]

Glenn, I've also shot some PBS stuff. Isn't amazine consider what they pay how very tech qual oriented they are? So when talking about linier... and there is one up here... are we just talking about a complete tc re-stripe of the master?

 

[Nick Shaw]

Not adding pulldown is not really that big a deal for making 60i deliverables. At the worst, you need another step or two dealing with it.

Glenn

Sorry if I'm being dumb, but how would you incorporate 24p (or 23.98p) material in a 60i deliverable without adding pulldown?

You said in an earlier post that the situation where some 60i frames contain images from two 24p frames would not be allowed by a broadcaster. How can this be? Surely it is the nature of pulldown that this will always be the case.

If I'm missing something due to my 25p/PAL centric experience then I apologize.

 

[Michael Hastings]

HDV not accepted

HDV not accepted

I would suggest to you that HDV is being used much more often than anyone would like to admit - I say this because I rent to a lot of these producers. I think what typically happens is that they take it into their edit system with an AJA or similar board and then it just becomes DVCPRO100 or whatever flavor they like, and then is output to whatever flavor is required.

Thanks for response,

Just wanted to be clear that redcine gives me edit masters that meet the minumum tech specs.

I was certain the RED answer was "YES" but needed to know before I pitch a broadcast executive - specifically since rule 3 paragraph 2 states, "all content to be shot in native delivery format." Let's hope their lawyers understand 4K downrezzing should be exempt:bleh:

Also of importance is the use of "accepted" broadcast quality conversions per rule 3 paragraph 3 - one frame off and they'll kick it back READ NO CHECK for final installment, aka, the producers salary. I think this is more an online post issue in the RED work flow?

It all takes time - first mini-DV was not accepted only 16mm and today S16mm, 16mm and HDV are not accepted at all! (yes there are exceptions to this but clearly defined).

 

[Chris Kenny]

I'd guess these requirements are spelled out so that if a broadcaster isn't happy with the quality of material, they can point to the appropriate paragraphs to avoid argument when rejecting it. If you're giving them stuff that looks like it was shot on low-grain 35mm stock, it seems unlikely they'd be complaining because your camera doesn't have the right number of chips.

 

[Chris Kenny]

Sorry if I'm being dumb, but how would you incorporate 24p (or 23.98p) material in a 60i deliverable without adding pulldown?

I'm pretty sure what Glenn was saying was just that it isn't a big deal if Redcine doesn't have the ability to add pulldown (which we still don't know), because you can always add it later in the process.

 

[GlennChan]

Sorry if my explanation wasn't very clear! I'll try again to the best of my ability.

Suppose your timeline is 23.98fps, with non-drop frame timecode.

You can introduce 3:2 pulldown.

When you convert from 23.98 to 59.97, some of the resulting 60i frames are a mix of fields from two different 23.98 frames. You cannot have this situation on frames that the program should cut to black. Only one of the fields will be black (but you need both of them to be black).

(guessing here) If the broadcaster specified all timings in 59.97 NDF timecode, I think this problem is avoidable since you can specify timecodes at whatever seconds and zero frames. By using these particular timecodes, you know that they are 59.97 frames that aren't comprised of material from two 23.98 frames.

But in any case, you can't do that since they specify timings in 59.97 DF timecode. 59.97 DF timecode slips out of sync with 59.97 NDF timecode, you you end up specifying some frames that are problematic.

2- If you have a 23.98 HD master, one solution is this:
-Make your 23.98 HD master.
-Downconvert to SD digibeta, adding 3:2 pulldown at the same time.
-Use the downconvert as a source tape for the final SD dbeta master. In a linear bay, you would assemble everything correctly with the right timings. You're now able to easily black out the problematic frames. And all the other packaging tasks, like inserting closed captioning, making a version of the master for each broadcaster, adding credits + logos + bumpers, shorter intro sequences, etc. etc.

You can avoid this by doing your online in a 60i timeline. But sometimes you don't want to online in a 60i timeline (because you'd spend a lot of time on cadence removal for effects), so you might end up solving things in the linear bay.

Where 3:2 pulldown in the VTR or Redcine helps is if you have the option (luxury???) of onlining in a 60i timeline, and don't have a linear bay to do your packaging (not all facilities have a linear bay, and not all of them are HD capable).

3- The more compelling reason to implement 3:2 pulldown in Redcine is when you need to online in a 60i timeline (i.e. you need the 60i vs 24p look because the DOP/client wants it).

 

[Ken Corben]

Very cool solution?

Very cool solution?

Well if it really is drop frame that causes the problem, then best shoot 23.98 or 59.94 drop frame in the camera.......

23.98 or 59.94 DF in camera seems like a great option/solution provided:

1) Redcine to offline (720P?) does not become a render monster?
2) FCP conform list for 1080i 59.94 DF online is doable?
3) 2K or eventually 4K DLT or HDD of edit master to efilm for 35mm print isn't another $20K at Laser Pacific to conform?
4) Best scenario yet is that I hit "OK" on my Mac workstation and FCP and Redcine creates the digital master for 2K or 4K digital projection - SCHWING!

 

[Nick Shaw]

Ah, Glenn, I get it now. You're talking about the situation that would occur if a broadcaster had specified that each part of a programme be eg exactly 10 minutes long, and cut to black at exactly 10 minutes and zero frames for the commercials. If you made a 23.98p 10 minute edit, then added pulldown when laying to tape, it is possible that a cadence slip could cause a single field of picture to occur on the first frame that should be black. I can see that might be an issue. My experience of delivering to UK commercial broadcasters is that the tape does not cut to black immediately at the end of the programme. Each part, and indeed the entire programme, normally ends with a holding frame which extends 10 seconds beyond the duration on the clock. It is the broadcaster who cuts to black/commercial. Don't know what the situation is in North America, obviously, but would this work for you? In fact even if the broadcaster specified black at exactly 10 minutes, you could lay to tape with a hold, then insert edit 10 seconds of black over the hold afterwards.

A more serious, and potentially harder to solve, problem would be if the cadence slipped such that the first field of the programme/part was black. Then if the broadcaster cut straight to the programme from anything other than black, there could be a single field flash of black before the programme started. This situation could again be solved by eg having a clock that ran up to 00:59:59:00, and starting the programme there with a one second 'padding' lead in (could be a freeze) and then doing a three second insert edit of black after the layoff.

This process would add a small amount of time to the layoff, but since you would need to roll the tape back to these frames and check them anyway, the time needed for a couple of insert edits would be negligible, and could even be done as a front panel edit on the deck.

Sorry for rambling at such length, but I just thought I would put down what I would do in this situation.

 

[GlennChan]

Right, doing insert edits would be a way of doing things. I guess the point is, if you online in a 24p timeline, it's a two-step process to create your 60i master. Versus one step if you online in a 60i timeline. The extra step isn't really that big a deal.

 

[S. Um]

Why not just use fade in and fade out? That way you'll have some padding for the broadcaster and for yourself.

 

[GlennChan]

I don't believe fades will work. Why would they?

 

[Ken Corben]

I have not seen or used fades in broadcast deliverables as they are not encouraged by broadcasters or distributors. It is a possible work around in the technical issue discussed here but I doubt an acceptable one.