Welcome to our community

Be a part of something great, join today!

Log in
  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Latency in HD-SDI...

A

Albert C Martin

Well-known member
Joined
May 13, 2009
Messages
99
Reaction score
0
Points
0
Age
38
Location
Ft Lauderdale, FL
We currently own two Epic-M cameras and have been using them in a live switched production environment. I am a huge fan of Red and we've designed our entire video system in our newly constructed facilities with these cameras in mind. The result is an interesting blend of cine-style and broadcast in a live environment.

One thing we are battling at the moment is the latency coming off the HD-SDI port on the back of the camera. In setting the HD-SDI output to 29.97p we encounter around 2 frames of latency coming directly off the brain. Under 23.98p we are closer to 3 frames of latency. This is causing us problems with the latency on the screens in the live environment not looking good.

I'm just wondering if there's anything that can be done to reduce the amount of latency we're experiencing? Is this just inherit in the design of the Epic hardware? Is this possibly a future firmware-addressing release? Will the Pro-I/O module (when released) have less latency?
 
A lot of cameras have latency, 2 frames is pretty normal, at least from my experience. This of course is more for the smaller camcorders and other cameras not specifically designed for live situations. It really isn't until you get to the bigger broadcast ENG style cameras that the latency problems are minimized. Yes, RED cameras are pretty high end and NOT camcorders by any means, though they are designed to be digital cinema cameras, I don't think working in a live production environment was that high on the list for the RED team, and personally, I don't see why it would need to be.

Hate to say it but you're looking at the wrong type of camera for what you want.
 
As much as I don't want to just appear negative in a post, I'm confused by your reasoning.

Using EPIC in a live production scenario seems willfully misguided. The camera is not designed for this, you gain no benefit in the RAW workflow as you're taking the HD-SDI stream (which is designed for live monitoring) and you have no remote racking or control of the cameras such as you'd find on a studio camera.

Added to that the latency inherent in a feed which is debayered from a much larger sensor, and you have possibly the least suitable studio camera on the market.

I suppose you have 'depth of field', but other than that I just can't see it. Can you explain your resoning in choosing EPIC for this?
 
Without knowing specifics of your setup, I would offer the following....

Many vision switchers have latency. 2 frames is common, I have seen worse. What processing is between switcher and Imag? This will also play a part. As an example, a Snell and Wilcox ARC150 has 2 frames latency when performing a conversion.

Are you in 5k on the Epic? Chances are if there is latency it is because a format/down conversion is taking place. To be expected.

I won't say it's misguided... I have plans to do similar things, aiding a one off OB whilst iso'ing to SSD for re-conform and cinema release in the future. But it's not going to be without some teethng issues along the way.
 
I don't want to sidetrack the discussion too much in debating "why" we went with the Epic cameras and whether or not they are the best pick for what we are doing. I'll speak to it briefly though. Are the Epic's generally suited as the best cameras for live application? No. Our setup is a bit a-typical and the choice of going with the Epic vs. a standard broadcast camera was made with much thought behind it.

We've been using a Red One camera for a couple years now and have really fallen in love with the RAW workflow, resolution, and look of the footage from the camera. At the time we were using the Red One during the week for typical production work: filming promotional material, creative pieces, and material for our television show. During the weekend we were using it to record and replay our production to a satellite location.

I've been following the development of the Epic cameras since we purchased our Red One. Some of the added features (1080p out, remote capabilities, modular form factor) made me think more and more about their possible uses in a live environment. I know that others, such as the great Steve Gibby, have used the Red One's in live switched concert environments as well and the Epic's seemed even more suited for such uses.

Our live productions consist of about 40% music performance and about 60% speaking with various produced video pieces sprinkled throughout both the music and the speaking portions. We also have a television show we produce and air every weekend.

There were multiple reasons for deciding to go with the Epic's for our uses; our two big ones were:

1. The ability to stick an SSD drive in each camera and record off 5K RAW ISO's for post production. We produce a weekly television show so the ability to edit portions of our music together with full RAW ISO's from each camera is a very big plus for us. In our old facilities we were running SD and any time we wanted to record our music for television we would need people to run our IMAG cameras in addition to recording on non-hardlined cameras (our Red One, Epic's and a Canon 5D) We had to split the talent up and know that our live audience wouldn't even see more than half our cameras in the show. So the thought was instead of running two separate systems to marry the two together. This way we could switch all our cameras in the live environment and also utilize ISO's recorded off of each individual camera for post production.

2. The "cinema style" shallow depth of field. We really fell in love with the look and feel we were able to achieve through the Red cameras when recording our live events for television. The shallow depth of field, lens flares, and soft "film look" work really well especially during the music portion of our production. (Here's a piece we shot in our old facilities: http://youtu.be/1YmzqXLGq5s) Even during the speaking portion, the speaker looks great and his skin tones are soft and wonderful vs over sharpened drawing attention to every wrinkle. Every time we would produce a piece for TV we would say "wouldn't it be nice if our IMAG on the weekend looked like this?"

Other smaller reasons included the whole modular approach to the Epic giving us a great amount of future-proofing in our systems. With the quick release system we can also quite easily pop an Epic out of the live switched environment and use it in the field for a more "typical" usage of the camera. This ends up saving us money because instead of buying a bunch of cameras that are only used live on the weekend, and then buying a bunch of cameras for post work, we buy cameras that can be used during the week for post work and on the weekend for live work.

As for "sacrificing" things that usually come with a "typical" broadcast camera, we haven't really needed to sacrifice all that much. Iris is still shaded remotely from our control room behind the stage. We are using Bartech gear wired directly to the cameras to accomplish this. Focus and zoom are run from behind the camera like a typical broadcast setup using a combination of Heden/M-One motors, custom Bartech gear and Fujinon controllers. As far as our operators are concerned, they are running a normal camera. Tally is functional although we're tweaking the housing as it attaches to the camera. CCU control will be run through Ethernet but right now is just set up before the show directly on the cameras or wirelessly through the RedMote.

Hopefully that helps explain some of our thoughts and decision processes when we decided to go with the Epic.
 
I am totally agree with Albert.
Epic will merge these two world in a single one. The new Canon mount and future Epic S are also in this trend. I dont want to buy a Sony anymore, even for live show, television, and for filming my dog and daughter !

Olivier
 
From further testing it looks like the Epic yields about 2.5 frames of latency while the Red One only has about 1.5 frames.

I'd love to hear from someone at Red. Is this just something inherit in the design of the camera or is it something we could see improved with future firmware updates or modules?
 
Albert, is there a latency difference between 2k, 3k, 4k and 5k or is it consistent across all?
 
jimhare said:
Albert, is there a latency difference between 2k, 3k, 4k and 5k or is it consistent across all?
Click to expand...

I did test across all different resolutions that were available to me and it was consistent across all. The only difference would come if I would change the camera to output at 23.98p which would add about a frame or so of additional delay vs. 29.97p. Also tried disconnecting the LCD but no real difference there, maybe a 1/4 of a frame of latency improved.

I noticed in the manual (page 128) that the HD-SDI output is switchable between 1.5GHz and 3GHz mode and that it could output at 59.94p when in 3G mode. I'm assuming this is coming in a future firmware? When switching the camera over to 59.94 the HD-SDI output still pumps out a 29.97p signal.
 
It is a problem at times when operating off non-red monitors. I have found myself missing or late on the shot. I have found the Red monitors better/quicker!

I would definatly like for the delay on the hdsdi to be decreased for steadicam and other remote applications.

Prost,
Rich
 
Spoke with Red and sounds like they are aware and working on the issue. Good news for sure! Love the fact that Red listens to their customers and makes improvements ... so awesome!
 
You must log in or register to reply here.
Back
Top