Thinking about timecode lately. Am obsessed....

[Jonathan Levin]

Hi everyone.

I am really getting nuts getting into the nuts and bolts of sync sound (for me anyway) and wanted to discuss timecode.

My basic knowledge of this is that a camera and audio recording device can be synced using timecode, thereby making sync in editing as easy as matching numbers. (Correct so far?)

Where I am getting thrown are the different "flavors" of timecode syncing. For example, my desired Sound Devices 633 has no less than nine timecode modes:

Record Run, Free Run, Free Run Auto Mute, 24hr run, 24hr run Auto Mute, External timecode, External timecode Auto Record, External timecode continuous, and External Timecode Auto record continuous!!!!!

Holy crap!

Rather than go into all these and drive you all nuts, Let's say I am a one person crew (which I am) and I'm thinking the easiest thing would be to somehow have the recorder start as soon as I hit record on the camera, as well as stop. Is this even possible? This would be really cool. Is that just a simple timecode cable (BNC?) from camera to mixer/recorder? Obviously more is involved when you are doing a multi cam shoot, but that's another time.

Or do you have a better way?

Is the first thing you do is "Jam sync" the two devices? From what I understand the camera is the external slave that controls the recorder???? And what the hell are "user bits" and do I need to even concern myself with this?

Jonathan

I realize the easiest and possibly the lowest tech approach would be to slate each and every time you start and stop the camera and recorder.

[Edward Carlson]

To run the audio recorder when the TC starts to run, set your camera TC to Record Run, and the recorder to External TC Auto Record. The units would have to be connected by a cable or wireless TC system. When the camera rolls, the TC will start. The audio recorder will see the TC rolling and also roll, with the same TC as the camera.

[Rick Reineke]

Make sure both devices are also set at the same frame rate.
BTW, TC alone does not guarantee a frame accurate or drift-free environment. Both or all other cameras, audio recorders and such would need to be gen-locked, typically with a master Tri-level sync generator.
For normal time code operation, one can usually ignore the user bits.
SMPTE TC and synchronization methods can get rather confusing. There's plenty of books available.

[Jonathan Levin]

Ed and Rick.

Thanks for the input. I appreciate that.

Ed- It sounds like I should be focusing on "Record Run" for my purposes. I'll concentrate my study to that for now.

Rick- I'm assuming that there must be a setting on the recorder that I can set to say, 30p, the same as a camera.

So here's another question, the camera I'm usually renting for work is a Canon XF305 and I may upgrade my video camera to an XF205. Both camera have four additional inputs/outputs: Genlock/sync out, Timecode, Monitor (for external video monitor), and 3G/HDI-SDI.

If I am doing a single camera set up, would the only cable I'd need to connect to mixer/recorder be the Timecode from camera to mixer/recorder? I know that with multi camera set ups you get into the whole Genlock 3G/HD-SDI thing.

Good to know I don't have to worry for now about "user bits". I am also aware that even with todays modern "crystals???" that sync can sometimes drift a frame or two after about 20 minutes. But not as bad as the days of film and tape.

I've also just learned that there is no capability to accurately timecode sync a DSLR, and that manual slating is best for that. Or get one of those timecode generator things, which I am not going to get into.

I'll try to look for some books on timecode. There wasn't much on University of YouTube, or other searches.

[Rick Reineke]

LTC can be recorded on one of the audio tracks. Some NLEs can convert it to a TC stamp and place it accordingly on the timeline. A smart slate will also display it. Depends on the camera what frame rates are available. Usually 24 (23.96), and 29.97 DF and NDF. I only know basic info about camera settings.

[John Willett]

I think that nowadays the timecode running at "time of day" is the standard preferred.

[Rick Reineke]

I concur with John, most prefer TOD. It's more of a constant. I think I've only used 'record run' once with a wireless TC link to trigger the audio recorder. The (inexperienced) camera dept. insisted on it and there were problems, especially in post.. naturally this was audio's fault. (me)

[Jonathan Levin]

Ok. Now confused. Is time of day a selectable timecode mode? Or is it something that is automatically written at the same time that the timecode is generated?

Looking at the Sound Devices manual, I don't see anything about Time of Day, unless it is called something else.

Thanks fellows.

[Brian P. Reynolds]

Timecode can be used in SO MANY ways......

If you are doing a recording where time is NOT critical then running it from 00:00:00 is the way to go as this gives a continious numbering.
If you are going to use several discs / tapes why not identify each disc by disc 1 = 01:00:00:00 and disc 2 = 02:00:00:00, disc 3 = 03:00:00:00 This works VERY well for camera shoots of a simple nature.

Time of day works well for split system shoots where recorders (video or audio) may be seperated. TOD also works well for single camera shoots where a producer / script assist can look at a watch and identify a take by just using time of day.

For more accuricy you may wish to connect the 2 units together either by cable of RF sends, for say a 3 camera 1 audio shoot using 'user bits' and 'TOD' code. ie, Cam 1 = 01: +TOD code, Cam 2 = 02:+ TODcode, Cam 3 = 03:+TODcode.etc etc etc.

Just imagine doing a 7 day shoot with (4 cameras + 4 Audio) of the local police / fire dept and "just" using TOD code... ALL the recordings would be the same regardless of which / day / date.
7days x 4 cameras = 28+ discs ALL with similar code and 28+ discs of audio with the same code......56 discs of confusion.

TOD would be useless in a DOCO spanning of a year of interviews / footage of perhaps a large building project or company staff interviews etc. in that case using the UserBits to include the date and TOD would be more usefull.

Remember timecode is just a way of marking each frame in an indentifible and searchable way.

[Seth Bloombaum]

You set up time of day by setting Free Run as the mode on all devices, jamming from a Preset timecode that you set on your master device. If it's currently 1:53pm, set the preset to 13:53:00.00 and start it rolling. Then jam all devices. Voila, time of day timecode. (hours:minutes:seconds.frames, depending if your particular device's preset function offers frames)

With some practice and an accurate clock, you can get your timecode to match actual TOD within an half-second or so.

This is also very handy when other syncing methods have failed for some reason; you always have unique (for a day) TC that matches within a half-second. Knowing what video and audio clips go together and having rough sync is more than half the sync battle; from there you can fine-sync by hand if all else has failed.

DO use all the sync tools, but TOD code can give you a fairly robust fallback when things go sideways. If for some reason you can't jam sync, carefully use the preset functions on all devices...

P.S. as mentioned above, also assure that all devices are set to NDF... or all to DF. DF will be ever so slightly more accurate to actual TOD, if that matters.

[Jon Fairhurst]

Someday, we will move from timecode to PTP - Precision Time Protocol. It's based on IEEE 1588-2008, was originally developed for computer networking, and has been adapted for various industries. As TV studios & stations move toward IP infrastructure setups, PTP can be used to sync audio and video within sub-microsecond accuracy. This is important as delivery times of independent streams have unknown and independent delays.

This can be especially important for next generation broadcasts that could include multiple views and multiple audio options with high-use streams (e.g. English in the US) being broadcast and low-use streams (e.g. Estonian in the US) coming over the network. It can also be adapted for high frame rate video, such as 120 fps and beyond.

PTP on Wikipedia:
Precision Time Protocol - Wikipedia, the free encyclopedia

Here's a nice PowerPoint presentation called "Genlock in the cloud"
http://www.ieee802.org/1/files/publi...SMPTE-0513.pdf

Note that PTP isn't just for replacing timecode. It would replace the whole black burst / genlock / timecode infrastructure.

SMPTE's 33TS Synchronization and Time Labeling Standardization Committee is drafting the ST 2059 standard suite:
* ST 2059-0 Overview of Standard
* ST-2059-1 Generation of Signals
* ST-2059-2 SMPTE PTP Profile

This info doesn't affect the practical aspects being discussed in this thread above. This is about what we will be working with in the future.

Won't it be cool when we can sync audio and video in a multi-camera shoot by simply connecting the cameras and recorders via local Wi-Fi?

[Bruce Watson]

Originally Posted by Jon Fairhurst

Won't it be cool when we can sync audio and video in a multi-camera shoot by simply connecting the cameras and recorders via local Wi-Fi?

As it should be.

[Jonathan Levin]

So this just FINALLY occurred to me:

If you set timecode to FreeRun on recorder/mixer, the clock continues regardless of anything being recorded or not.

So if the recorder and the camera are initially synced (jam synced?) then you could start and stop both the recorder and the camera anytime and ads many times and still be able to line up sync to that 24hr running clock by just lining up the time! (As long as you don't go over 24hours) So in this case you wouldn't have to slate anything.

Have I got this right? Seems to simple to be true. Probably really basic but a mountain of info to me.
Jonathan

[Rick Reineke]

"If you set timecode to FreeRun on recorder/mixer, the clock continues regardless of anything being recorded or not"
Yes.
Many pros use small battery powered 'lock boxes' which are quite accurate, the cameras/recorders TC are jam-sync'd to them. They run $300-500+ each and each recorder needs one.. But drift could still happen over long run times.

[Jonathan Levin]

Hi Rick,

Is drift a giant factor even with today's modern digital equipment? For a basic 20 minute interview, single camera to mixer/recorder would I need to be looking to add those lock box things?