Timecode is what you get when each frame (or field) is tagged with its own identity, a number, by a reference timing device (a clock). You could have all kinds of coding systems, but the most commonly used is the SMPTE 12M-1 and 12M-2 (12M) Timecode, usually as Linear Timecode (LTC).
It looks somewhat like this: HH:MM:SS:FF (Hours:Minutes:Seconds:Frames), where the limit of FF is the frame rate of the video.
Why do we need timecode?
Think of it as buying a high-quality watch. Once you adjust the time perfectly, you have reliable time – until the batteries run out at least!
What makes a basic timecode system?
Most prosumer and professional cameras come with in-built timecode, which is in the form of metadata for digital video. The DSLRs on the other hand, don’t have SMPTE timecode (though they have something), except for the Canon 5D Mark III, that is.
Your requirements of timecode depend on which features of timecode you want. Do you just want a reference, as in when you’re shooting with one camera – you log the footage and then get to editing (EDL) directly, where your only problem is syncing audio and video?
Or, do you have a multi-camera setup that needs to be synced precisely, maybe for stereoscopy, HDR or broadcast, etc?
DSLR timecode is okay if you’re recording audio in-camera. For professional audio, you’ll need to find a way to generate SMPTE timecode and add that information to the video somehow. The HD-SDI protocol is excellent for timecode delivery, along with audio and video.
All in all, the simplest timecode generator that is also reliable is the Ambient Recording ACL 204:
It includes a sync generator and timecode display, and supports up to 1080p60.
For more control, you will need the Ambient Recording Clockit Controller – ACC 501; or if you prefer LANC, try the Lanc Logger – ALL601.
The simplest way to sync everything
The el-cheapo method, which also happens to be more than a century old, is to use a slate/clapperboard, like the Cavision Professional Production Slate.
For the electronic version, check out the Ambient Recording Time Code Slate ACD 301.
If you prefer wi-fi and a tablet for a slate, try the Clockit Timecode App:
For a full understanding on how everything works together, check out this video:
All this is just an introduction to the world of timecode. Like with everything else, the more devices you add, the more complicated things become.
A full studio setup is beyond the scope of this guide, but for basic production work, even for live broadcast, the above systems should suffice.
Remember, no matter how good your timecode hardware, if someone isn’t logging it right, then the entire exercise is basically pointless. It’s like having a dictionary that is not sorted alphabetically.
For this reason, one uses a timecode reader or logger like the Katamount Scriptlinc:
Hopefully this would make the life the AC and editor easier.
The last thing on the timecode list is the translator. A translator converts timecode from one timecode format to another, and is not within the scope of this guide. But I’m mentioning it so you know such a thing exists.
SYNC and GENLOCK Devices
What if you have multiple devices that need to work in tandem with perfect ‘frame accuracy’? Such a system demands a master clock. Big broadcast studios have more than one master clock, in case one fails. Everything depends on it.
Generator Locking (Genlock) is the technique of synchronizing each device to a master clock or signal generator. In broadcast, achieving perfect genlock is critical so there are no ‘gaps’ between switches to different signals – imagine a quick black jump every time it cuts to a different angle while watching your favorite show or sport! With the advent of HDTV, things have become a bit easier.
Genlock is also used for syncing cameras perfectly for stereoscopy, so that the images captured are at the exact same point in time. This makes 3D a whole lot easier to watch. The added benefit of perfect synchronization is the ability to also sync lens movements, like zooms or focus pulls.
A simple genlock system can include the following components:
For signal pulse generators, try the Tektronix SPG8000.
You might be wondering what a tri-level signal is. In very simple terms, a bi-level genlock signal is like holding on to dear life with two arms, while a tri-level signal has three arms. This makes a tri-level signal lock stronger, in electronic terms, and the signals stay locked.
Frame synchronizers are usually found in good production switchers, but for a semi-stand-alone solution, try the Grass Valley ADVC G1 Multi-Functional Converter with Frame Sync:
One cool tool compatible with all the cameras providing genlock in this guide is the Tessive Time Filter.
It eliminates the judder and temporal aliasing caused by 180o shutters. It works with all the cameras that support genlock as listed above.
This brings us to the end of this chapter. You might be feeling quite overwhelmed by all these devices and possibilities. Luckily, the future will entail simpler and more widely adopted standards (HDTV, Ultra HD or 4K) that should make life a whole lot easier.
Special fields like streaming, stereoscopy, etc., will be dealt with in later chapters.
We have also come to the end of the ‘image’ part of this guide, which, as we all know, is only 50% of any video. The other 50% is audio. Let’s get to it.