You have latency generated within every digital video device you've got in tbe chain -- including camera, switcher, HDTV, and who knows what else.
Latency in that scenario is additive, and cannot be resolved in large mrasure except by strategically delaying the audio signal -- but where you do so in the signal chain is critical (perhaps it's not good to make the correction, for example, even via the video switcher's menu, if it posesses that capability -- but some consumer HD and 4K televisions even sport Audio Delay feature, that's menu accessible. Check that option out, and/or purchase a black box that performs such a delay for you).
Now, in a large oresentation space such as a church auditorium, concert hall, conference room, etc., a helpful trick to minimize the tension such latency arouses in your audience is to ensure your presenter is not standing directly "beneath" or "beside" the viewing screen(s) from the majoity of your audience's point of view -- that's an additional, practical benefit for the Stage Left/Stage Right dual-[projector] screen setups found in many large venues in worship centers and the like.
BUT WHAT ABOUT TACKLING THE MAGNAMINOUS ADDITIVE LATENCY CAUSED MORESO BY THE CHEAPEST QUALITY VIDEO DEVICES IN THE VIDEO SIGNAL CHAIN?
It would serve you well to minimize the use of unnecessary digital "enhancement" techniques you might have running in any of those digital video sources, video processors and display devices.
For example, within the camera, adding to the latency generated by analogue to digital conversion to SDI, you might investigate whether you've got image stabilization switched on. If so, shut it off -- and look for other possible latency-generating culprits you can do without.
Check Blackmagic Design's catalogue for MiniConverter accessories that might be equipped to aid you further, in wisely, i.e., strategically aligning audio and video signals where needed most, after you've taken remedial steps suggested above.
I hope you find this read useful.
Cheers!
Peter
courtney wrote:Hi there,
I have a Canon XF205 which is connected to a BlackMagic ATEM1 ME 4K Production Switcher via SDI. I then have SDI going out to two LED domestic TV's from the Auxiliaries. The TV's have BlackMagic SDI to HDMI converters and then HDMI into the TV's. The picture is great however the audio is miles ahead of the video.
The audio however is coming through our Auditorium sound from radio mics into an Allen & Heath desk. Is there a way to fix this latency issue?
Thanks
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