What is sync?
Professional productions typically record sound and picture on separate devices. Some productions, especially documentaries, use multiple cameras. Each camera and sound recorder produces its own files for each take. Sync is the process of lining up these files on an editing timeline.
How can I automate sync?
Manual syncing is tedious and error-prone. If you use the same clock to timestamp all the files you record, you can sync them automatically in post-production.
What does Dish do?
Dish takes public radio signals from atomic clocks and embeds precise timecode in cameras and audio recorders.
Does Dish work with my camera?
Yes. Dish works with any camera/sound recorder that has a microphone input. Dish works with mirrorless cameras and DSLRs. Dish works with ARRI and RED cameras. Dish even works with cell phones that have microphone inputs.
What’s with the name?
Dish receives time signals from satellites, like a satellite dish.
What do I need to configure before I can use my Dishes?
Nothing. Dish is entirely plug-and-play. You turn it on, plug it in, get satellite lock and go to work.
How do I make sure all my Dishes are jammed to the same clock?
All Dishes everywhere in the world report the same time-of-day timecode, in UTC (more specifically, in International Atomic Time).
How much does a Dish drift in 24 hours?
It doesn’t. As long as you have access to satellite signal, even intermittently, the Dish doesn’t drift. The satellite signal is accurate to about 60 nanoseconds. By comparison, a 30fps frame is 33 milliseconds long. Satellite timing error is one half-millionths of a frame.
What happens if I lose satellite signal?
Dish continues to run on its internal clock and report accurate timecode. The built-in TCXO clock keeps accurate time between signal acquisitions.
How do I connect a Dish to my camera?
Dish comes with an 1/8″ TRS socket. The simplest way to connect it to a camera is plug into an 1/8″ or XLR audio input.
Do I lose scratch audio when I use Dish with my DSLR?
No. Many DSLRs disconnect onboard microphones if you plug in an external input. For just this use case, we’ve included a microphone in the Dish. If you plug a Dish into your DSLR, you get timecode on the left audio channel and scratch audio on the right.
Wait, you record timecode on an audio track?
Yes. This is the most straightforward, lowest-common-denominator way to get timestamps into your files. Camera vendors go out of their way to make sure that picture and onboard sound are synchronized, and the modulation we use was specifically designed to pass through audio channels.
What signal does Dish output?
LTC. Originally developed by SMPTE, Linear Time Code is an international standard. Most recent version is available from the International Telecommunication Union.
Do I need to buy into a whole new ecosystem to use the Dish?
No. LTC is an international standard and widely deployed technology. Most timecode hardware on the market utilizes LTC, including systems that cost many times as much as Dish. Many NLEs support LTC natively (e.g., Avid, DaVinci). A number of stand-alone software utilities exist that extract timestamps from LTC files. We are working on our own, free and open-source desktop LTC app.
Powering the Dish
How do you power a Dish?
Dish runs on 2 AA batteries.
How long do the batteries last?
A pair of fresh, high-quality alkaline AAs lasts a day. We recommend rechargeable NiMH AAs.
Wouldn’t an internal lithium battery be better?
We’ve considered that, and may incorporate it into an upcoming version of Dish if customers want it. One big advantage of AAs is that you can always replace them. If your PA forgot to charge the built-in lithium, you’re out for half a day.
Does Dish have any limitations?
Dish gets accurate time anywhere it can get a satellite signal. Anywhere your phone can determine its location, Dish can receive accurate time.
Is there anywhere Dish doesn’t work?
Satellite signals cannot penetrate underground or underwater. Additionally, US export regulations restrict satellite receivers over certain altitudes and over certain speeds. So if you’re shooting on a nuclear submarine, or in a missile silo, or on a missile in flight, Dish can’t get accurate time.
But I need to shoot in a missile silo!
Sounds like an interesting shoot! Make sure you turn your Dishes on and get a signal before you go underground. Your Dishes continue to run on internal TCXO clocks. Your Dish will tell you if it drifts enough to need a re-sync with the satellite.
Your technology is useless. I use good old-fashioned [insert process name] and have no need for your gizmo.
If you are happy with your current workflow, we support you in continuing to use it. You probably built your toolset over a long period of time, and we respect your comfort with it.
Isn’t this what the clapper slate is for?
The clapper slate has been with us since the invention of talkies. Its longevity speaks to its usefulness. An assistant editor looks for the first frame where the sticks are closed, and lines that up with the audible clap on the soundtrack. He or she has to do that for every take and every scene. The process is tedious and error-prone. On a big production it adds cost and schedule. On a low-budget project, manual sync may well result in “infinite post.”
Syncing by hand sucks, but don’t NLEs sync using audio waveforms and AI?
There is some amazing post-production software. Sync by sound works best when the shoot is in a controlled environment, with the cameras and the microphones close together. The algorithms work especially well when they can latch onto a loud sound, like the clapper. The results are less consistent when filming in noisy environments such as street interviews or BTS. Sync by sound fails entirely when the camera cannot hear the same sound as the microphone, e.g., shooting through windows, shooting in a car, or with telephoto lenses.
What’s the problem with telephoto lenses?
For sync by sound, basic physics. Sound travels much slower than light. Speed of sound is 1,125 feet per second. During a single, 30fps frame, sound travels 1125/30=37.5 feet. If your boom mic (or lav) is on the talent, and the camera is 40 feet away, you’re out of sync by a whole frame. This comes up all the time when filming public speakers. If your camera is in the back of an auditorium, its audio is several frames behind the master track.
Syncing by sound has its limitations, but you can simply jam-sync all your cameras in the morning, and they are good through lunch.
Jam-sync gets most of the way there. It requires higher-end cameras and a a responsible adult to jam them to a master clock, several times per day. In contrast, Dish works with any camera, requires no manual intervention and never drifts.
I’ve heard about setups that have a master timecode generator and wireless distribution.
They exist. The gear costs $5,000 to $15,000 and it takes a dedicated professional to run the system. You want to make sure the wireless is running, that no other transmission is stepping on the master clock, that all the receivers are on the right frequency and that they all run at the same frame rates. Dish is a lot like this system, only it costs 1/20th and our master transmitter is in orbit 20,000 km above the Earth–and the government is looking after its health.