S-Video output to VGA switcher delay

[rafiki]

Appreciate any advice for a novice.

We have just setup the following and have a huge delay with the video running behind the audio. I presume it is the switcher from S-Video to VGA that is creating the issue.

Setup

• Canon XHA1 S -Video outputting via S-Video cable to Kramer HQV VP-728
• Switcher outputting in VGA to Sanyo projector.
• V-Mixer M-400 taking inputs from multiple mics and sending XLR to the camera and speakers.

• Have Firewire 800 output running at the same time from the camera to an iMac.

From the research I have done I think the issue is the time it takes the switcher to process S-Video input and outputting to VGA. We initially recorded in HD then with the delay switched to 16:9 which reduced the delay, but still out of sync.

Key question is if I upgrade the switcher will the S-Video to VGA ever catch up? Or???

Any advice appeciated! Thanks!

[waynehoskins]

Hi, welcome!

The basic places where you're likely to introduce frame delay are in transcoding, resynchronization, and scaling. In your case, the presentation switcher is suspect, as is the projector if it's not being driven at its native resolution.

Our setup is synchronized analog composite straight through to the projectors, with TV cameras and switcher and router all timed, and even with that we have a 3-4 frame delay on IMAG that's entirely within the projectors.

[Brad Weber]

Also add some potential latency in the camera providing an analog S-Video output. Combine that with the latency of the switcher and the projector scaling and it all starts to add up.

[Nick Mawer KUK]

Hi Rafiki,

in general terms the less you ask the scaler to do, the quicker it does it. So a scaler will usually scale a YPrPb signal with less delay than a composite video signal.

The other thing to double check is that you are providing your display device with the "preferred" resolution. If you send a WUXGA image from the scaler to a projector that can prefers WXGA, then you will be introducing more delay as the projector will downscale.

If you have any more questions - please feel free to contact your local Kramer company. If you are in the US, contact our office in New Jersey.