BUYERS GUIDE-WIRELESS over a wireless link. But it seems to me the obvious way to go is DVB-T2 with an H.265 encoder, which is where we are heading. Our current latency is one frame. Anything more than that would just not be suitable for 4K. Until we’re 100 per cent sure that we can have a 4K wireless camera at the side of a football field that has one frame or less of latency, there’s no point.” The SOLO7-OB Tx camera-back transmitter is Domo’s first 1080p60 solution. It has integrated camera control and swappable RF modules. It’s able to work at 4:2:2 chroma and does H.264/ MPEG-4 AVC video encoding. Its latency ranges from 1s to an ultra-low 10ms and fits directly onto the back of an ENG type camera. At NAB this was demoed with a bi-directional link using MIMO IP Mesh technology firing 26 Mbit/s in combination with a Sony HDC-P1 camera mounted on a remote-controlled pan and tilt head. The unit takes HD-SDI from the camera, encodes the audio and video data to IP, and transmits it wirelessly to Domo’s MIMO IP Mesh system. “Because IP Mesh provides an exceptionally high bit rate for bi-directional IP links, we can transmit A/V data one way while camera control and remote control data travels the other for control of pan and tilt, plus camera control data for colours, iris, etc. within the camera.” Typically, this would require three separate frequencies, but with the SOLO8 SDR and IP Mesh combination, it’s three data streams in a single bi-directional link, which makes the entire remote camera and control system completely wireless. This, claims Delport, is a genuine “first”.
already hard task of sending 4K. An additional critical parameter is the mobility of the drone,” says Kanonich. “The wireless link must be able to maintain the connection in all directions and while moving.” Amimon previewed a solution for 4K straight from the lab. “The latency we are already able to present is practically zero, and the quality is just amazing,” claims Kanonich. “The unit’s size we envision to be the size of the Connex mini. There’s no need to increase size to support 4K UHD. But it will be next year before we launch it in actual products.
“Drones require the support of both high range and transmitter robustness, adding to the already hard task of sending 4K” BBC RESEARCH BBC R&D’s system is completely bespoke using relevant parts of DVB-T2, DVB-NGH and MIMO to maximise channel capacity. “Having extra bit-rate allows for lower latency video coding,” says project engineer John Boyer. “The latency of the system is variable as interleaving can be dialled in by the user to improve link ruggedness, but the video
a Domo’s SOLO8 SDR and IP Mesh combination can transmit A/V data one way while camera and remote control data travels the other
COMPRESSION COMPLICATION The data rate required to send 4K is about 19Gbps. “When you are trying to compress that amount of data, all the issues related to compression such as quality loss, added latency, and increase susceptivity to errors are increased dramatically,” says Uri Kanonich, vp of marketing at Amimon. The firm’s Connex technology doesn’t use regular compression, rather a unique videomodem solution. “This allows us to send today HD 1080P signals with less than 1ms latency and the same chipset will allow to do the same for 4K UHD,” says Kanonich. The Connex mini is the latest addition to the Connex range. Unveiled at NAB, this is a ultra-small transmitter supporting 1080p, full HD wireless video at a range up to 1500ft, ideal for airborne drones as well as other unmanned systems. “Drones require the support of both high range and transmitter robustness, adding to the
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