Unmanned Systems Technology 028 | ecoSUB Robotics AUVs I ECUs focus I Space vehicles insight I AMZ Driverless gotthard I InterDrone 2019 report I ATI WAM 167-BB I Video systems focus I Aerdron HL4 Herculift

88 Focus | Video systems processor cores that sit alongside the encoder core in a multi-core chip to boost the radio link to give more margin for the video. Using the additional processing power to implement multiple in/multiple out (MIMO) systems that use up to four transmitters, receivers and antennas can give an extra 3 dB in the radio link margin – the equivalent of doubling the transmission power, allowing a higher video bandwidth without actually increasing power consumption. This gimbal acts as a video motion detection payload and ‘server in the sky’ for persistent surveillance (Courtesy of Controp) Several suppliers of radios with built- in encoders now have MIMO capability, and these need radio amplifiers that can handle two, three or four concurrent RF chains. Embedding processor power into the integrated units with the video encoder, radio subsystem and multiple amplifiers allows the input and output power of the amplifiers to be monitored in real time, including the MIMO chains. That allows the gain of the amplifiers to be automatically adjusted in real time to match the data rate of the video, reducing the RF power when the video is a lower rate. This approach also allows compensation of any drift in gain, power, signal-to-noise ratio or other variables that come from changes in temperature or frequency. It is a common reason why a video link does not always operate well. Tuning and filter circuits are October/November 2019 | Unmanned Systems Technology The Advanced Video Codec (AVC), also called H.264, is a widely established video compression technology, and is used across terrestrial broadcasting, DVD and many wireless video links. It is based around the discrete cosine transform function, and uses a series of I-frames, and full frames with intermediate P and B frames. P frames use data from previous frames to decompress the image and are more compressible than I frames, while B frames use information from both previous and forward frames to get the highest amount of data compression. AVC supports resolutions up to 8192 x 4320, including 8K UHD video, with each pixel’s colour defined by an 8-bit value. This compresses HD video to 2 Mbit/s. High Efficiency Video Coding (HEVC), also known as H.265, provides 25-50% better compression at the same level of video quality, or substantially improved video quality at the same bit rate. It supports resolutions up to 8192 x 4320, including 8K UHD, and adds support for more complex pixels with 10 bits of colour. HD video is compressed to around 1 Mbit/s. Versatile Video Coding (VVC), also called H.266 or MPEG-I Part 3, aims to provide a 30-50% improvement in compression over HEVC and is looking at how to add AI capabilities to the compression. The first version of the standard is being developed for the end of this year, with a final standard by the end of next year and hardware encoders available by June 2021. It should support resolutions from 4K to 16K as well as 360 º videos that require higher data rates and 16-bit colour. It will also support variable and fractional frame rates from 0-120 Hz, and is expected to be 10 times more complex than HEVC. A VVC test model has been built to make sure all the compression systems produce a standard output. Video standards The MGW Ace Encoder and Decoder use Vitec’s HEVC GEN2+ codec with zero latency compression, allowing a 16 ms latency across the whole video link (Courtesy of Vitec)