NDI|HX transported a stuttering 720p30 video stream across the internet at 744 Kbps. The wind blowing the tree was the motion component.
Philo T. Farnsworth’s reported first words upon seeing the first TV image, which happened to be transmitted wirelessly, were “There you are, electronic television!” Some 95 years later, TV broadcasters and viewers rely more on wireless electronics than ever.
The first live TV remote was in 1927 when Philo T. Farnsworth picked up a simple straight-line image with his first ‘image dissector’ camera tube and transmitted it to a receiver in a separate room of his San Francisco laboratory, well before commercial TV was invented.
Throughout Farnsworth’s pioneering mechanical and electronic TV inventive work, and up until TV went digital the early 21st Century, analog outside broadcast remote TV technology leap-frogged itself with improvements such as broadcast TV microwave bands and satellites, but the workflow process of RF backhauls and creating remote video and multi-camera remote video production has remained relatively unchanged.
Over most of the history of TV, audio and video content from the field was either backhauled by the telephone company to the station or transmitted by microwave radio to a studio receiver. The signal was one-way, also known as half-duplex mode. Full-duplex mode, 2-way multi-channel field communications, such as PL, IFB, return video and prompter needed separate RF channels for each source and destination.
Party Line TV Production
Digital video over IP can be a full-duplex, full-time, party line. Full-duplex A/V over IP is what makes Zoom meetings possible. Full-duplex is what the industry leveraged to overcome pandemic challenges and discover fresh ways to gather, create and backhaul live TV content to air. Taking advantage of the unique benefits of full duplex over a single IP connection has become known as Remote Integration Model (REMI).
My local TV station friends and I have been exploring new ways to backhaul live remote camera video into our TriCaster production switcher with better results than the Matrox Video Maevex encoders and decoders and line-of-sight Ubiquity 5 GHz Wi-Fi microwave radios we’ve been using. Last year I bought a NewTek Spark 4K for that purpose. My friends recently purchased a pair of Teradek Cube 600 series encoder/decoder systems. I field tested my Spark with NDI 5 and a Cube encoder/decoder system. They were as similar as they were different.
NDI is a high-performance standard that allows anyone to use real time, ultra-low latency video on existing IP video networks. It was invented by NewTek and is royalty free as is the NDI Software Development Kit. The result of this marketing strategy is that NDI has been integrated in hundreds of products from multiple manufacturers across the growing spectrum of video applications. The largest difference is that the Cube encoders can use a cellular data USB card to connect with an ISP to send data to a decoder in the studio.
The top right corner of each NDI 5 app window shows the usual “X” and “_” and a new “?”. The "?" links to written information and a video tutorial about the specific app. Nice touch, NewTek.
Best Industry Bargain, Ever
NDI 5 Tools is a free download, and the tools now all work as promised. NDI 5 Tools is a suite of powerful apps such as Studio Monitor, Test Pattern generator, Bridge, and a half dozen other useful apps, that can all be downloaded as a package to a PC or Mac for free.
Without NDI 5 Tools, all a Spark 4K can do is convert and connect HDMI to a 10 GbE NDI network, which pops up as a source choice on a TriCaster on the NDI LAN. The NDI 5 Studio Monitor displays any NDI source on the LAN. A second monitor HDMI output from the computer displaying Studio Monitor full screen can be a HDMI production switcher input.
It’s much easier and less expensive to use NDI 5 Bridge to bring remote NDI sources from the WAN into the LAN, where they can be seen on NDI 5 Studio Monitors, and as a source on a TriCaster or similar NDI-capable decoder on the network.
Everyone On One Encrypted Network
The full-duplex beauty of NDI 5 allows any NDI source to be seen and used at any logged-on remote site and the host location, including NDI PTZ camera control. Sources such as return video, prompter, and dedicated NDI audio intercom options are also part of NDI 5. One of the many benefits of duplex communication is that NDI sources use no network bandwidth until called on-line for recording or decoding.
NDI requires more than 100 Mbps to pass an uncompressed HDTV signal. It doesn’t tolerate slower speeds, such as that of a Ubiquity 5GHz band IP microwave system. They don’t talk to each other. The NDI 5 Bridge Tool allows users to access and control the speeds of NDI|HX for slower networks. NDI|HX is NewTek's implementation of h.264 (AVC) and h.265 (HEVC) compression.
The only difference between the Host and clients in NDI 5 Bridge is that the Host sends the client’s operator IP and login instructions by email. Once logged on, everyone can perform the same functions. NDI 5 can serve all NDI sources when requested among multiple clients with proper digital credentials from the Host.
I bought my Spark 4K when NDI 5 Tools was first released. The NDI 5 Bridge tool is necessary to enable remote cameras over the internet, but Bridge remained in Beta until a couple of months ago. Data speeds and internet connections for the Spark are managed by NDI 5 Bridge.
You don’t need NDI Tools Bridge or Studio Monitor to decode NDI. Several companies such as Magewell Electronics and BirdDog make stand-alone NDI to HDMI decoders and devices. On a 1Gb LAN, my Spark 4K tests indicate Spark likes about 120 Mbps to deliver active 1080i HD to a NDI destination. More on bandwidth later.
Cube And Core
Teradek Cube encoders and decoders are hardware devices complete with a small text screen and joystick control to display and navigate menus. The encoder can log on to local Wi-Fi to communicate with the decoder on the LAN. Teradek Core is software that allows configuration of Cube devices on a local web browser or through the cloud. The Cube 600 encodes and decodes h.264. Cube 700 systems are like the Cube 600 systems, but they encode and decode HEVC and h.264, and were unfortunately over the budget.
The Cube 655 encoder was set to reduce 1080i60 to a 768 Kbps stream to fit through the 800 Kbps bottleneck. It worked.
The Cube system is a bit more remote production than REMI, because the stand-alone decoder output is HDMI or SDI. It is not designed to simultaneously transport video in both directions. The Cube encoder stream is h.264 that can be assigned to a specific remote decoder IP address and Port.
In the Cube encoder menu, or on its Cube screen, simply assign a destination IP address, assign a public or private Port (9719 is the default), set the Primary Video Stream Output to SRT, set the mode to Caller and press Start Stream. The stream may be decoded in several ways, some hardware, some software. The easiest way is with a stand-alone Teradek Cube decoder at the studio that converts the stream into HDMI and SDI for production switcher integration.
For point-to point intercom, the Cube 600 series requires a second decoder set to a different Port for the headset. The 600 series encoders and decoders both have a mini jack for Apple ear pods and compatible headphones. Intercom is about as deep into REMI as the Cube system gets.
In a controlled studio GbE LAN the Spark and Cube performed exactly as advertised. Both were easy to setup and operate, and stable with bandwidth headroom to allow both systems to operate error-free. QoS and QoE were outstanding. Using the public internet for transport was a slightly different story.
My rural home is on Stone Age internet. The best my ATT DSL ISP can do is 7 Mbps down, 800 kbps up. Downloading and watching 5-6 Mbps 1080i video streams works fine. Uploading a 5 Mbps 1080i video stream does not. Attempting to observe a 5 Mbps stream from my house at a remote location using NDI 5 Tools Studio Monitor and Bridge resulted in hearing the camera audio but the video was black. That was the moment I realized my 7 Mbps home internet service was only good for 800 kbps up. Reality check! Challenge accepted.
NDI|HX encoder settings offer four preset levels of quality or can be user-variable by dragging a mouse.
To compensate for the slow upload speed, NDI 5 Bridge allowed me to dial the bandwidth of the HEVC signal to 10% (1.1Mbps @1080p60). I also switched the camera output to 720p30. In fact, that signal was received at the other end of the WAN at 768 Kbps. It was rather herky-jerky and unsuitable for broadcast, but it proved the Spark 4K and NDI 5 can stream video over a WAN at less than 1 Mbps if necessary.
I performed a similar test with the Teradek Cube 600 system after updating the firmware in both the new encoder and decoder to the same version. I dialed back the Cube 655 encoder to 768 kbps, left the camera output at 720p30 and was amazed at the h.264 stream results. The video quality video was surprisingly good, but it skipped a frame or froze for a few frames every couple of seconds. At the time of this Cube test my friends at the TV station where the Cube decoder was were working on one of their digital subchannels. They put my 768 Kbps SDI stream on the subchannel they were working on, so I could see my feed from home on live OTA TV at home. The video wasn't quite ready for primetime, but it looked better than expected and it was a first.
The 800kbps Bottleneck Test
In my impromptu super-slow ISP bandwidth stress tests, Cube performed better than Spark, likely because Cube was designed specifically for internet WAN use. Spark was designed to convert and transport uncompressed NDI video on a Gigabit Ethernet (GbE). NDI 5 makes using Spark on the public internet possible, practical, and easy with NDI|HX compression controls.
NDI 5 requires the operator to manually open a typically private local router port at both ends or it won’t work. Note the Warning Triangle icon because the Port exception wasn’t set yet.
NDI 5 found and provided a Host local IP address, Port, and automatically or manually assigned Encryption Key that are easily copied as a group to the clipboard to email to the remote unit operator and pasted into the remote NDI 5 Bridge.
Both systems were easy to connect to the studio, but I’m uncomfortable making changes in a stranger’s Home Internet Gateway to make NDI 5 Bridge work. "Seems harmless enough" when I'm the invited guest is not a good idea.
Our powerboat racing productions usually beg permission to setup field cameras on private property that can provide AC power. Typically, it’s a private condo or house with a great view of the racing action on the water and some homeowners are very nice about helping us out. Asking to connect to a homeowner’s private high-speed internet connection and then asking for their Gateway Modem/Router password and login info is a bit too much for me.
In a similar situation, Cube would be easier because it only requires an IP address and a public Port that’s already open. All you need is the Wi-Fi password, a place to set the decoder near the production switcher input panel, and enough CAT 5 or 6 to reach the Gateway Modem/Router.
There are two major differences between Spark with NDI 5 and Cube. Spark costs significantly less and NDI 5 is free. But, the NDI system requires a fast computer loaded with NDI 5 at both ends to monitor and control settings. Factor that into the total cost. Cube devices are standalone. They can be operated without a computer at either location, although manually entering some settings and addresses with the tiny built-in joystick can be a bit challenging. Cube costs more, but it is small and simple to haul and setup in temporary remote locations.
Is NDI 5 and Spark or Teradek Cube right for your station or project? It depends on what you want to do and how you want to do it.
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