Frame delay?? Live application

[John Ott]

Thanks to you all for your tremendous insight into this camera.

DOES THE XL-H1 HAVE A PROCESSING DELAY?

With HD-SDI and genlock, this becomes a compelling option for mutli-camera shoots. What about for live, imag (image magnification) shoots?

Most (all?) of the prosumer (XL-1 and lower-type cameras) have "trick modes:" sepia, B/W, posterization, etc. Because of the trick mode capability, there is about a 1.5 FRAME delay in the camera EVEN IF YOU DON'T USE THE TRICK MODES. I learned this on the Sony BRC-300 ( http://tinyurl.com/5b4c7 ). It seemed like a good, low-end option for SD-SDI: 3CCD, SDI out, genlock, 16:9-capable, etc. I demoed one about 6 mos ago and noticed the delay. I called sony and they told me about the 1.5 frame delay. I've noticed it on every prosumer (or trick mode) camera since.

To see the delay, connect the camera to a video monitor. Put a subject infront of the camera. Have the monitor and the subject in the same sight-line. Have the person clap. Notice on the monitor that you hear the clap and then see the clap. With a professional, broadcast-grade camera, there is no (perceptable) delay.

In a live imag application, a delay of 1.5-2 FRAMES is unacceptable.

If the XL-H1 has delay, it wouldn't prevent me from purchasing the camera for many production applications. It would, however, prevent me from purchasing 3 or 4 for a live, imag application.

Your input is greatly appreciated. TIA.

[Chris Hurd]

The delay that you're referring to is in all DV / HDV camcorders and happens only when monitoring the live audio output... there is no delay in the actual DV or HDV recording itself. Just like the XL2, the XL H1 has a menu option which allows you to keep the audio and video in sync when monitoring a live shoot.

Go to the Audio setup menu and select Audio M. Set, then choose either Normal or Line Out. Normal provides real time output. Line Out adds the required delay in order to match audio with video so that they're in sync when monitoring live output. Hope this helps. Welcome to DV Info Net,

[Nick Hiltgen]

So Chris are you saying that if this camera were to be mixed with HDCAM cameras on monitoring the live out put there would be a 2 frame delay but the actual camera would be recording matched time code.

However, if that's the case does that mean if you were to mix the XL-H! footage with the hdcam footage by recording HD-SDI out straight to a deck, there would be a frame (or two) delay on the record deck, that would differ from the genlock in?

[Chris Hurd]

Nick over SDI or component out I have no idea. I would *assume* for whatever an assumption is worth that the delay is not present over SDI or component out because that happens before compression, but like everybody else, I would like to hear Canon USA confirm this for sure.

[John Ott]

Chris, I appreciate your reply, but having the audio and video locked up on the recording is not my concern. Any delay through the camera is of no concern in a multi-camera studio, or live-to-tape production (assuming the cameras are locked-up with each other). My concern is for imag--that the video being passed from the camera to the switcher to the projector(s) is behind the live audio being pumped through the PA.

If I were providing imag for a concert and my imag screens are just above or to the side of the stage, I cannot afford to have any noticable frame delay. If the crowd starts clapping to the beat but the video is 2-3 frames behind, it's going to screw up everybody. Due to the internal processing delay on a projector (roughly 1 fr), if the camera adds another 1.5-2 fr (as prosumer cameras do), I cannot use the XL-H1 and must use a traditional-type broadcast camera that does not introduce delay.

I know the Sony & JVC HDV cameras introduce the 1.5-2 fr delay. B/C the XL-H1 has more pro-like features (HD-SDI & Genlock), I'm wondering if the delay is still there. B/C the Sony BRC-300 has SDI and Genlock but still has delay, it leads me to ask if the XL-H1 has delay even with its pro-like features.

[Chris Hurd]

John, I think this is going to be a question for Canon USA. Call the help line at 1-800-OK-CANON and drill through the menus until you get to a live human being. Most likely they'll have to research your question and get back to you later with feedback from the XL H1 product manager.

By the way I don't think I've ever seen a live performance where the audience's hand clapping wasn't out of sync with itself... you know, the entire hall isn't always going to clap together right on the beat exactly... seems to me that one simultaneous "clap" from a hall full of people is going to be spread across a good portion of a finite amount of time anyway, depending on the tempo.

[Pete Bauer]

Yeah, I'm a bit out of my element here, but I'm having a hard time seeing how this is a practical issue. Sound travels at about 1100 ft/sec so every 37 feet away from the sound source gives a 1-frame audio delay. So a couple frames of video delay should be about right for the audience at a medium-sized venue.

[Chris Hurd]

Agreed; there's a built-in audio delay already depending on the size of the venue due to the limited speed of sound compared to the speed of light. I agree that in this case, a video delay of a frame or two is probably a *good* thing in a large hall.

[Kevin Dooley]

The problem comes in that EVERYTHING has latency. It might not even be a full frame, but once you go through switchers, projectors, etc. the delay can add up. Honestly though, using various DV cams for shoots like this (VX2000s, XL1s, DVX100s, etc--all for roaming stage cams...) I can't say that I've ever seen an unusable delay. I've seen the delay, yes... but Joe Schmoe Average doesn't even notice.

[Brian Wheatley]

Hi,

I've recently had to do a live relay for a conference where the delay through to the projector was enough to see lip sync problems for the audience viewing experience. Now I know it is a delay from the H1 as my XL 1s had no delay. I'm off to my supplier for them to look at it and I'll let you guys know the score.

Bri