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Wireless HDMI/SDI transmitters/receivers compatibility

PostPosted: Mon Jul 08, 2019 1:04 pm
by ColinV
Hi,

I have an ATEM Production Studio 4K and do events with 4 or 5 cameras depending on the occasion - a Sony, a Canon, and the rest GoPros.

I'm looking at doing Wireless transmission from these cameras rather than running SDI and HDMI cables all over the place, taping them down etc.

Any product you can recommend that works with Blackmagic Design stuff?

Thank you!

Re: Wireless HDMI/SDI transmitters/receivers compatibility

PostPosted: Wed Jul 10, 2019 11:30 pm
by Roman Pytkin Pekarek
Im using Teradek Bolt .. Friend have Vaxis and works too .. I think all transmiters must works ..

Re: Wireless HDMI/SDI transmitters/receivers compatibility

PostPosted: Fri Jul 12, 2019 3:41 am
by Dave Del Vecchio
I would expect most wireless transmitters that work with standard broadcast resolutions to be compatible with the ATEM.

It's possible though that you might have trouble using 5 wireless transmitters simultaneously in the same area though. Depending on what frequency band the wireless transmitters use and how much other RF activity there is at those frequencies, you could easily run into interference issues that limits the number of wireless setups that you can practically use at the same time.

A lot of the low-delay (1 or 2 ms) WHDI wireless systems use Amimon wireless chipsets that operate in the 5 GHz frequency band. These systems use a 40 MHz frequency channel to transmit video up to 1080p60 resolution, and are capable of switching between different channels to avoid congestion. There is some information about how this particular system works in this technical paper:
https://web.archive.org/web/20091211041 ... 0final.pdf

I believe there are twelve license-free 40 MHz channels available in the 5 GHz frequency, although the actual number can vary slightly depending on the country. In any case, this suggests that if there are no other devices operating in this frequency space but the wireless video transmitters, then perhaps things might work (if each transmitter uses a single 40 MHz channel). However, this is a best case scenario and probably not a great real-world assumption.

The 5 GHz band is increasingly being used by wi-fi devices (802.11n and 802.11ac) and other higher bandwidth wireless devices. So it's probably unlikely that this space will be totally empty, and you may find that a lot of the available channels are already used by other devices reducing the number of remaining free channels for wireless video transmission.

There are some other wireless video systems that use H.264 or other more aggressive video compression that may use less bandwidth and allow you to accommodate more simultaneous wireless video signals. Most of these systems tend to have more latency (often at least 1 frame and in some cases up to several hundred milliseconds or more).

GoPro used to have a wireless transmission system designed specifically for their cameras called the HEROCast (I think the system was actually made by VISLINK). It was a bit on the expensive side, and I'm not sure if it is still being sold: https://gopro.com/en/us/news/herocast-p ... ive-events

And as with anything wireless, you may have to try things in your environment to really be sure that it will work as expected. A hard-wired system will almost always be more reliable than even the best wireless system.