Clapper Boards

[Thundercross]

Hi there

This is the off-topic section, I know how a clapper board works and what it is used for. My question is regarding Smart slates with the electronic SMPTE time code with LED numbers. I have never used one and I wonder how they work?

How do they work and how do I actually use the timecode as an editor? Is it stamped to the audio and video? What is the cable/RF connector from the clapper board connected to and what is generating the timecode?

I know there are different ways like Jam and free run but this is unclear to me.

Thanks:ph34r:

[Shawn Booth]

You're better off going to www.locationsound.com

When a smart slate is open, the timecode displayed is the day's actual time and when you close it, it displays the date.
The sound mixer jam the slate from his generator which is linked to his recorder.

[Thundercross]

Thanks, I just wanted to know who on set was generating the time code and it comes from the sound mixer.

I shot on 16mm recently and had a problem with the sound we were recording and we eventually ended up using a PD170 as a sound recorder :ranting2: and I had to sync it all up by eye and ear.

I am doing a shoot on RED soon and I want to ensure that I record to the camera and to a seperate recording unit. I just want to make sure that there will be no sync issues.

I'm on PAL here.

Thanks for you advice.

[Cail Young]

You should be able even to jam sync the RED to the sound recorder so that you won't even need to visually match timecodes. When you get close to the shoot it's probably worth posting in the Audio forum here to work out any kinks in your system.

[Thundercross]

Thanks I will do that for sure!

My question is more offtopic of RED now, in terms of digital LED time slates. Why are they used? and how does the system work?

I saw some pic here on another thread where there was a cable coming from the clapper board?? Just curious how it works, you knw the clapper boards you see in hollywood behind the scenes on DVD's...??

Thanks again.

[Chris Burket]

You can use an electronic slate a couple ways. First off, its fed timecode via a cable. Your sound mixer and jam it to his record deck which runs time of day or you can velcro a comtec on the back of it and feed it via wireless connection to the mixer's deck. In this case it is displaying record run timecode. For sound sync shoots, we always jam it and display time of day. You could attach a comtec to the red camera and feed it time of day timecode as well, but you don't need to.

Using the comtec/record run method is usually just done for playback (music videos). So that you can easily sync the video to the song track.

Why are they used? It's easier and more accurate for a telecine operator to use the timecode instead of the clap. Really, we only hit the slate as a backup, they hardly ever use it.

In music videos, you NEVER want to hit the slate, because no sound is being recorded, the only useful thing for sync is the running numbers.

[Cail Young]

They have an internal timecode clock; the cable feeds a timecode signal in LTC (LINK) (http://en.wikipedia.org/wiki/Linear_timecode) to the clock, which 'jams' to that signal and can (usually) continue rolling that timecode for hours without requiring re-syncing.

EDIT: I should say, some have internal clocks. Some will require constant LTC signals, as mentioned above.

As to the higher-level "why"; on film the timecode on the slate refers to the timecode on the sound recording device; when you're in editorial you use that number to sync up your seperately-recorded ("double system") audio rather than relying on manual identification (although generally there will still be a percentage of shots where the slate isn't useful, generally very tight shots where you can't get a TC slate small enough or tailslates where the eager camera op stops rolling before the clap).

In the case of video (and digital cinema by extension) it's possible to stamp video frames with the same timecode as the audio even in double system; in this case the numbers on the slate are a back-up in case of losing timecode metadata for the video.

You can of course run the other way, and stamp your audio with the TC of the video, but for RED at the moment there is no TC output from the camera - yet.

[Thundercross]

on film the timecode on the slate refers to the timecode on the sound recording device

Ahh... that is exactly what I was looking for!! Thanks. :biggrin:

So the cable is not always plugged in it is only used once just to sync (jam) and then it is unplugged??? This can de done wirelessly as you say too.

Thanks.

[Thundercross]

For sound sync shoots, we always jam it and display time of day

Why time of day and not REC timecode?:waaa:

[NateWeaver]

For Rec timecode, a few things would have to happen:

1-One device, either camera or sound recorder would have to be TC master.

2-For #1 to be true, one device would have to record the timecode output of the other. Neither device, while being able to accept outside jams, is really setup for this.

3-TOD TC gives more unique numbers, with less potential for confusion, especially if the user bits have the days date.

4-Would also require a hard line to feed TC to the slate, or wireless. The former is a pain, the latter eats batteries, and sometimes has drops.

[M Most]

Why are they used? It's easier and more accurate for a telecine operator to use the timecode instead of the clap. Really, we only hit the slate as a backup, they hardly ever use it.

I take it you've never worked in a telecine facility.

Time code slates are notoriously inaccurate, and all claims to the contrary, do drift . There is almost always an offset between the slate TC and the actual sound TC and that offset can change throughout the day regardless of how often the slate is resynched. They are used because in many telecine facilities, time and money do not permit "popping" of the tracks (film term for "finding and noting the time code for the sticks on each shot") ahead of time, so using the slates will get you relatively close. But in many of these same facilities, a second person is in the room hand checking each shot as it is recorded to make sure the shots are in sync by jogging through the frame on which the sticks close. For other facilities - ours included - this is wasteful and cumbersome, so we use a device made by Aaton (the Indaw) to bring in sound as files (usually easy these days because they come in that way) and locate the sticks ahead of time. That is the mark that's used in telecine, and the slate (the time code, that is) is a backup. In some larger facilities, more elaborate systems are in place that also use a variation on our system (automatically locating the sticks on the sound files and synching the tracks using that mark).

Relying on time code slates to provide accurate sync is far less reliable than doing it the old fashioned way. And I say that after many years of painful experience.

[NateWeaver]

It's interesting to note the difference between what info gets passed between ACs, and what really happens in post. Given that the link between the two is often third-hand reports via sound mixer, it's not much a of a surprise.

When I was a young 2nd, that was what was told to me too: "Just make sure they can see the numbers clearly, no movement, for just a beat, then sticks as a backup".

Now that I've done both sides, I know there's a lot done on set that's not as important as they may think, and some things that could use more attention.