In order to displace an incumbent technology, a new technology must provide significant benefits to users. Streaming video provides greater flexibility, more content and new viewing and engagement models over traditional linear TV. However, the quality of experience (QoE) of linear video delivery has been better, with better picture quality, lower latency, faster channel switching and fewer playback issues. 

But with access to greater bandwidth and reduced latency, such as offered by 5G, it can propel streaming to an unqualified benefit over linear.

Ericsson forecasts a total of 190 million 5G subscriptions by the end of 2020. While the COVID-19 pandemic has slowed some 5G deployment, it is still estimated that, by 2025, 5G will have 2.8 billion global subscribers. Of that total, 88% are projected to be mobile.

At the same time, the COVID-19 lockdown has driven digital transformation quickly, and consumers have spent a huge amount of time online. According to figures from Verizon, during the lockdown, there was a 26% increase in global video streaming traffic and a massive 71% increase in gaming traffic compared to normal pre-COVID usage.

5G will transform video away from traditional linear TV by offering users better engagement and new ways to consume content, such as multiple stream viewing and volumetric video, which is key for AR and VR. It also presents significant benefits to service providers, like the ability to address new markets and improve monetization.

ADDRESSING LATENCY AND BANDWIDTH LIMITATIONS 

When streaming live events, especially sports, there is a slight delay between what’s happening on the field and what is being delivered on a 4G network—an average latency of around 50ms. When expanding this to other scenarios, like cloud-based gaming, latency affects the response time as well.

Some viewing activities are particularly bandwidth-intensive. According to data from Qualcomm, supporting 6 Degree of Freedom (6DoF) head motion parallax 360-degree video (such as for an Oculus Quest) consumes more than 200 Mbps. Below are Qualcomm’s bandwidth estimates: 

5G is expected to provide consumers with a seamless viewing experience because of its massive improvements on latency and bandwidth. 5G is expected to provide a 10x decrease in end-to-end latency. The faster speed improves the production of streaming live events on mobile devices. It can not only compete with fiber, but also give access to consumers who don’t already have access to very high bandwidth connections. Furthermore, 5G enables a lower cost per gigabyte ratio, which means that streaming capabilities will be more cost efficient.

For example, KT Corporation, South Korea’s largest telecommunications company, launched its 5G Olleh TV mobile app on time synchronized playback, multistream/multicamera for live content, low latency and 360VR on a 4K stream. With the VisualOn Player, KT’s Olleh TV Mobile users are able to watch music and sports the way they want, focusing on the camera angle or performer that they are most interested in. 

KDDI, the leading Japanese communications provider, is another example of offering new services to compel subscribers to upgrade to 5G services. KDDI’s au Smart Pass mobile app now features high-quality streaming video services for its subscribers, such as multiple streams synched on a single screen. The VisualOn Player enables new ways for Smart Pass users to experience live sports and concerts over a 5G network. 

BETTER AD DELIVERY, BETTER MONETIZATION

As 5G will improve the video performance, will it also contribute to video monetization? 

Conviva’s 2020 Q1 State of Streaming report showed 46.3% of ad opportunities were missed, either because of playback issues or lack of inventory to serve. The most common playback issue is the ad was not served on time, which means it does not play. When ads don’t play, or are not accurately tracked, the service provider doesn’t get paid. The greater bandwidth and lower latency of 5G will help with smooth handoffs between content and advertising and ensure that ads are served on time, and thus play.

The inventory issue is expected to be temporary, caused by many activities and businesses being shuttered, but the long term trend is toward greater spending on video advertising. For example, according to the IAB UK PwC Digital Adspend study, video has become the key driver for digital ad spend, encompassing approximately 44% of the £2.31 billion display market. 

 With 5G in place, service providers will have access to more sophisticated ad insertion and analytics platforms—even at the video player level. Higher quality ad delivery drives greater engagement, and granular tracking and analytics means more accurate reporting for advertisers to justify increased budgets. 

5G is already seeing successful rollouts in Asia. The impact of COVID-19—limiting live events but driving users to streaming video—has accelerated the rollout of more innovative and compelling streaming services to fill in the gap. In turn, digital transformation has been greatly accelerated. Bottom line, 5G will allow for higher quality and more engaging content to garner eyeballs.

Michael Jones is senior vice president and head of Business Development at VisualOn. 

FOSTER CITY, Calif.—A Silicon Valley startup says it will launch a new platform that will “radically lower video bandwidth costs” next month. 

Edge Video says the first test results of its SWAN (Small-world Wide Area Networks) showed a 5x reduction in bandwidth costs, compared with costs of existing server-based architectures. The system enables a live video stream to be captured by the SWAN technology and rebroadcast to viewers where each of the viewers' devices leverage the unused upload capacity to restream fractional portions of the video stream to other viewers.

"This is the most radical product to emerge in Edge Computing" said Joe Ward, CEO of Edge Video. "Video is by far the highest cost application per user on the internet. Here we are enabling a 5x reduction in network egress costs, resulting in a much higher video definition for viewers."

Edge says it's targeting a 10x reduction in bandwidth costs when it announces the next phase of Edge Video SWAN testing in July 2020, “where all cloud computing users at AWS, Microsoft Azure, Google Cloud and Oracle Cloud will be able to soon leverage the Edge Video SWAN technology to substantially reduce server bandwidth (egress) costs and increase video viewing definition as a result.”

More information is available at edgevideo.com.

SAN BRUNO, Calif.—A week after Google announced that it was downgrading its YouTube streaming service to standard definition in Europe to reduce bandwidth during the coronavirus pandemic, the company announced today that it will extend the policy worldwide, according to Bloomberg. 

The transition will take place over the “coming days.” Viewers will have the option to watch in HD, however the default will be SD. It instituted the policy last week in Europe, in response to a request by European regulators to Netflix and Amazon Prime to reduce bandwidth usage. 

As millions of citizens worldwide take shelter at home in response to the pandemic, this has greatly increased bandwidth usage throughout the day, instead of traditionally peaking in the evening, according to Google. According to researcher Sandvine, Google was the largest consumer of traffic volume on the internet in 2019, with Netflix in second. 

“We continue to work closely with governments and network operators around the globe to do our part to minimize stress on the system during this unprecedented situation,” Google said in a statement.

In November 2017, the FCC approved the deployment of ATSC 3.0 (aka “NEXTGEN TV”) for U.S. broadcasters. This historic decision gave our industry the authority to use the same 6 MHz channels for ATSC 1.0 to deploy the new standard, which combines over the air broadcast with IP.

“This new TV transmission standard promises to allow broadcasters to innovate, improve service and use their spectrum more efficiently,” the FCC said at the time. “It also has the potential to enable broadcasters to provide consumers with a more immersive and enjoyable television viewing experience on both home and mobile screens.”

The ability to broadcast 4K is one of the more attractive features of ATSC 3.0. When the FCC approved ATSC 3.0, 4K was just beginning to make inroads into the marketplace, while 8K wasn’t even a consideration.

Nearly two years later, people are beginning to take even 8K seriously.

In December 2018, Japan’s public broadcaster NHK—which had been touting its 8K Super Hi Vision for years—launched daily 8K satellite broadcasts on its NHK BS8K channel. 8K was also prominent at the 2019 International CES in January.

Currently the UHD 8K technology market is estimated at approximately $2.9 billion, but projected to reach $26.8 billion by 2024 according to research firm MarketWatch.

GETTING THE MOST OUT OF 6MHZ

With 33.18 million pixels and 68 billion colors, UHD 8K provides the best Quality of Experience (QoE), approaching human eyesight in pixel, density fields of view and color gamut (Ling Ling Sun, 5G And UHD 8K- A Developing Symbiosis). At 12 bit color and 120 Hz refresh rate, with HEVC encoding, the bit rate of UHD 8K is about 200 Mbps.

Currently, there is no digital terrestrial broadcast method that can deliver the 200 Mbps content in a 6 MHz channel. (The transponder bandwidth of NHK’s 8K satellite broadcast is 34.5 MHz. Using 16 APSK, the transmission rate is approximately 100 Mbps.)

For the 6 MHz channel, the maximum theoretical capacity of ATSC 3.0 is 57 Mbps. However, using current ATSC 1.0 transmission parameters and covering similar area, more realistic ATSC 3.0 capacity is estimated to be 26 Mbps, with 256 QAM, about 33% more than the 19.4 Mbps capacity of ATSC 1.0 standards.

There are several ways to increase the channel capacity in ATSC 3.0: Quadrature Amplitude Modulation (QAM), Multiple Input, Multiple Output (MIMO, support for 2x2 using polarization) and Channel Bonding (supporting two RF channels). Clearly, the current ATSC 3.0 standards can’t provide the needed 200 Mbps capacity for UHD 8K (see Table 1).

Digital terrestrial television broadcasting is defined by hardware infrastructure and technical policies/standards. Policies/standards often connect to other policies/standards to form a “policy/standard network.” ATSC 3.0 is a part of such a policy/standard network. Assuming that the hardware infrastructure of digital terrestrial television broadcasting remains unchanged, one can focus on the policy/standard network and use viable system of networking (VSON) to manage its complexity. In the VSON approach, a technology standard doesn’t exist in a vacuum—it coexists with its environment—UHD 8K is a perfect example of that future environment.

For a technology standard to survive, it must adapt to a new environment and co-evolve with it. There are two possible ways to achieve this.

One is to change policy in management, another is to increase services in operation. Policy defines the relevant environment, and operation provides the requisite variety and in ATSC 3.0, both changes are needed. In a policy change, ATSC 3.0 should support 20 MHz bandwidth. In an operation change, ATSC 3.0 should include UHD 8K and multiple UHD 4K services.

Specifically, an additional 20 MHz channel bandwidth is proposed for ATSC 3.0 to support a variety of new services. With 2x2 MIMO, 64 QAM and 20 MHz channel bandwidth, estimated capacity is about 130 Mbps. With future Versatile Video Coding (VVC), a UHD 8K program at 120 Hz frame rate can be compressed to a bit rate of 120 Mbps while a UHD 8K program at reduced 60 Hz frame rate could be broadcast without MIMO.

If UHD 8K service is about the future, then multiple UHD 4K service is about the present. Currently 4K TV household penetration in the U.S. is more than 30%, and 48% of non-4K TV owners plan to get a new TV within the next year, according to Leichtman Research Group. By 2024, the global market for 4K technologies could reach $144 billion, according to Market Research Engine.

Advances in coding technology and high capacity broadcasting channels will enable a shift from traditional single view live broadcasting to multiple view live broadcasting. This content diversity will increase viewer engagement, and potentially increase viewer loyalty.

In addition to enabling the new services, the 20 MHz channel bandwidth policy improves spectrum efficiency, simplifies management and saves on CAPEX and OPEX. This is because by merging three 6 MHz channels into one 20 MHz channel, two guard bands that separate the three 6 MHz channels are converted into a part of the 20 MHz bandwidth. Three 6 MHz channel transmitter sites are also reduced to one 20 MHz transmitter site. In a sense, it is a centrally managed spectrum shared by the three 6 MHz channel licensees.

However, the improvement of channel capacity alone isn’t enough for UHD. When spectrum bandwidth changes, the number of available channels will also change. As a consequence, channel sharing and frequency re-use are important factors to consider in spectrum planning. VSON provides a cybernetic platform for such planning, allowing dynamic channel sharing, optimal frequency re-use and SFNs to be monitored, controlled and orchestrated intelligently.

Channel capacity will always be an issue for broadcasters with the biggest challenge being spectrum availability. Without major resource and technology upgrades, will broadcasters be able to support future services when circumstances change? The viable system approach proposed in this paper provides a possible solution.

Ling Ling Sun is assistant general manager/CTO for Nebraska Educational Telecommunications.

Many thanks to Tom Butts for help in editing this article.

For a comprehensive source of TV Technology’s ATSC 3.0 coverage, see ourATSC3 silo.

To accelerate the U.S. deployment of 5G, the FCC is pursuing what it refers to as the “5G FAST Plan” (Facilitate America’s Superiority in 5G Technology). One of the plan’s strategies is to release more spectrum into the marketplace. High-band spectrum with about 5 GHz bandwidth will be released, across 24 GHz, 28 GHz, 37 GHz, 39 GHz and 47 GHz bands.

More penetrating mid-band spectrum is a work in progress, with targeted 844 MHz bandwidth, covering 2.5 GHz, 3.5 GHz and 3.7-4.2 GHz bands. Required for 5G, these spectrum bandwidths will be utilized to provide 20 Gbps download and 10 Gbps upload capacities, per base station, through technologies such as quadrature amplitude modulation (QAM), carrier aggregation (CA) and multiple-input and multiple-output (MIMO) etc.

NEW EMERGING SERVICES

5G technology has the requisite characteristics for new emerging services: Enhanced mobile broadband (eMBB), massive machine type communications (mMTC) and ultra-reliable and low latency communications (URLLC). These services will provide a platform for “anywhere, anytime” access to real-time broadcast media, for both content contribution and content distribution (5G and Ultra High Quality Content Creation and Distribution, Broadcasting & Cable). Quality of Service (QoS) and resilience in 5G networks will fundamentally improve the end user’s Quality of Experience (QoE), which is the most important factor in determining a viewer’s engagement and loyalty, especially for high quality content, such as UHD 8K.

Defined as “a measure of the delight or annoyance of a customer's experiences with a service,” QoE focuses on the entire service experience, not just QoS offered by 5G. With more than 33 million pixels and 68 billion possible colors, per frame, UHD 8K contains a vast amount of digital bits to be programmed into patterns of art, story and knowledge.

In fact, UHD 8K creates almost a “3D” effect, approaching human eyesight for pixel density, field of view and color gamut. It offers an experience akin to “looking out through an open window,” and evokes stronger sensory experiences for QoE (Table 1). Technology change is the driving force for viewers’ habits and UHD 8K offers a window of opportunity to bring viewers back to big screens.

A DRIVING FORCE

The demand for a high-speed, low-latency transmission network provided by 5G is perfect for UHD 8K. At 120 Hz frame rate, 12 bit color depth and 4:4:4 sampling, the UHD 8K data rate is 143 Gbps. With HEVC encoding, 200 Mbps bit rate can be achieved. Future video compression standard Versatile Video Coding (VVC) is 40% more efficient than HEVC, further reducing the bit rate of UHD 8K and approaching the minimal 5G network capacity of 100 Mbps, per device.

Clearly, UHD 8K is a use case and driving force for 5G commercial investment, and is likely to be deployed as an initial 5G application. Furthermore, the architecture of the 5G network ensures QoS and QoE for UHD 8K distribution. Viewers’ engagement and loyalty will in turn improve ROI of both 5G networks and UHD 8K content creation. The mutually beneficial relationship between 5G and UHD 8K makes them a true symbiosis in the making.

Broadcasting doesn’t exist in a vacuum—it coexists with its environment and 5G and UHD 8K technologies are that future and relevant environment. To be viable, broadcasters must co-evolve and transform with them (VSON Manages Network Complexity).

To manage the complexity of this transformation, a viable system approach should be taken. In the viable system (VSON) approach, the 5G network and broadcast network are two services in the operation of VSON. We may call this particular application of VSON a “converged media system” (CMS) (Fig. 1).

CMS provides an end-to-end solution for UHD 8K video consumers, from content creation to distribution. We immediately recognize the important roles of policy, control, orchestration, monitoring, and intelligence in the process of the transformation. In other words, this industrial transformation is not a small feat: it takes a system to transform a system.

Many thanks to Tom Butts for help in editing this article.

Ling Ling Sun is assistant general manager technology/CTO for Nebraska Educational Telecommunications.

ALEXANDRIA, Va.—Every time a new digital production standard gains traction, there is great stress on old infrastructures to carry state-of-the-art (i.e. “broadcast quality”) signals.

In the 1990s, it was SDI for standard definition, which had a data rate of 270 Mbps. That was so much more demanding than the analog signals that came before it, that it required new cables, new connectors, new patch panels, and of course new equipment to handle the digital signals. At the time, 270 Mbps seemed like a breathtaking data rate.

Then in the mid-2000s, broadcasters started upgrading their facilities to HD, with its data rate of 1.5 Gbps. That was for 1080i and 720p HD, and it seemed like a lot of data.

Until the push came for “full” HD with its 1080p frame rate and its demanding 3 Gbps of data. Video facilities that had installed HD-SDI were now upgrading products for a data rate twice as high as HD-SDI.

Although cables and connectors for 3G video are now common, the reality is that the frequency response of copper cables is starting to reach its limit at 3G. When 4K came along and we learned that its uncompressed data rate would be 12 Gbps, there were whispers that it was going to be impossible to send 12G video more than a short distance on coaxial cable.

Despite the whispers, some clever engineers tackled the challenge and there is now a 12G-SDI standard with cable and connectors that can be used to wire real-world facilities. It works and that’s good—although the higher the frequency, the more persnickety the cabling gets. At 12G data rates, a slight crimp in a copper cable or a bend radius that’s a little too tight will cause the signal to deteriorate quickly.

"LOSSLESS" COMPRESSION?

There is another way to tackle the problem, however. What if there was a “lossless” compression system that could reduce the necessary bandwidth by four or eight times, without adding complexity or latency?

That standard is being worked on right now, and it’s called JPEG XS.

“JPEG-XS is a newly evolving compression technology that is exciting because it is extremely low latency and also low complexity,” said Andy Rayner, chief technologist for Norway-based Nevion and the director of Nevion’s U.K. technology center. “It is an intra-frame compression—it is spatial only, with no temporal element. It is wavelet-based, and conceptually can be thought of as lots of tiny stripes of JPEG2000. The exciting thing is that where the base compression technology used for JPEG XS-TICO was visually lossless at a compression rate of 4:1, in JPEG XS this is doubled to at least 8:1.”

TICO (which stands for TIny COdec) is a precursor to JPEG XS that promotes a lossless 4:1 compression to permit 12G video to be carried on a single 3G cable. Many manufacturers in the video industry are members of the TICO Alliance, and the same developers are behind JPEG XS.

Rayner knows what he’s talking about. In addition to being awarded the Martlesham Gold Medal for technical innovation, Rayner received a technical Emmy for JPEG 2000 standardization.

When you think compression, you normally expect signal degradation, lots of latency as signals are encoded and decoded, and added power drain as powerful processors calculate how to compress and decompress the signals. JPEG XS specifically targets those concerns.

“I see it as having the potential to replace JPEG2000 as our de facto choice for mezzanine compression,” Rayner said. “The encoder-decode latency is only 32 video lines, which means at only a few hundred microseconds, this becomes negligible compared with other latency in the systems [especially wide area connectivity]. The compression has also been optimized for real estate usage on FPGAs, CPUs and GPUs, which means its use in server technology is also highly viable.”

SAFEGUARDING ADVANTAGES

One of the other goals of the team developing JPEG XS is that it not be specific to any resolution, and be capable of supporting future format requirements, while safeguarding the advantages of an uncompressed stream. These advantages include interoperability, visually lossless quality, multigeneration robustness, low power consumption, low latency in coding and decoding, ease of implementation, small size on chip (no additional DDR memory is required), and fast software running on general-purpose CPUs and GPUs.

“No other codec fulfills this set of strong requirements simultaneously,” said Antonin Descampe, founder of and compression technologist at IntoPIX, a Belgium-based manufacturer of signal compression and processing components. “JPEG XS can thus ‘compete’ with uncompressed in every aspect, and reduce bandwidth and video data significantly.”

There are lots of compression formats out there, including some widely used for their ability to maintain high quality for serious production work. Do we really need a JPEG XS codec?

“The main difference between JPEG XS and existing codecs from JPEG, MPEG or other standardization committees is that compression efficiency is not the main target,” Descampe said. “Whereas other codecs primarily focus on their efficiency, disregarding latency or complexity, JPEG XS addresses the following question: ‘How can we ultimately replace uncompressed video?’”

To many in the television industry, switching from an uncompressed format to a compressed one sounds unwise. The only reason to consider it would be due to the high bandwidth of uncompressed 4K video reaching the limits of what copper cabling can support.

That said, JPEG XS can make a real difference in bandwidth.

“The typical operating points for visually lossless quality with JPEG XS are around 10:1.” Descampe said. “However, it is important to take resolution and content type into account when identifying a maximum compression ratio. For instance, natural content usually reaches higher compression ratios for a given quality level. During its development, JPEG XS has been tested against the strictest quality assessment procedures (ISO/IEC 29170-2, ‘Evaluation procedure for visually lossless coding’), seeking the threshold guaranteeing an ‘indistinguishable flickering’ between original and compressed image—a measure often referred to as ‘visual transparency.’”

DIFFERENT KINDS OF CONTENT

Based on the tests performed by the JPEG XS working group, Table 1 shows the codec’s performance with different kinds of content (screen content, computer-generated images (CGI)) and natural imagery. The lower compressed bitrate in the table defines performance with natural content, while the upper range is for more complex content requiring full visual transparency.

For broadcasters, overall image quality is a big concern, but not the only one. Perhaps equally important is latency, and JPEG XS should address that concern as well.

“In terms of latency, using MPEG-4/H.264 and HEVC/H.265 in a live production workflow with multiple encoding and decoding steps would lead to a compiled latency of many seconds,” Descampe said. “JPEG XS has a microsecond-latency and can thus be run throughout a whole live production workflow without inducing the latency of a single MPEG-4/H.264 encode/decode step. Even though we need H.265 for the last mile to distribute it to the consumer, we try to avoid any additional latency in the production workflow before distribution.”

Descampe said that we should hear about the finalization of the JPEG XS standard around 2019 IBC in September.

“Concerning the status of the standardization process itself, JPEG XS Part-1 [Core Coding System] is published and available as an international standard already,” he said. “Part-2 and Part-3 [respectively profiles and transport formats] are finalized and being prepared by ISO for immediate publication. Part-4 and Part-5 (respectively conformance testing and reference software) are under ballot and shall be published by the end of this year.”

In addition to that standards work for JPEG XS, there are several ongoing liaisons between standards bodies and industrial organizations such as AIMS, VSF, SMPTE, TICO Alliance and IETF. The IP Showcase at the 2019 NAB Show hosted a presentation about JPEG XS in ST2110-22.

WORKING ON IMPLEMENTATIONS

Descampe said that several broadcast suppliers are already working on implementations in their soon-to-be-announced products. And he pointed out one more feature of the standard that makes it compatible with IP video requirements.

“JPEG XS uses a constant bitrate and is thus highly relevant for reliable video over IP transport, especially with compressed video being added to ST 2110 as ‘part 22,’” Descampe said.

Why name this new format JPEG XS? There is some precedent in the JPEG2000 system, which is also used for high-quality video transmission. Why “XS,” however?

“I think the funniest thing is the name,” Rayner said. “It literally stands for eXtra Small!”

Extra small or not, JPEG XS looms large to the people who have been working on it.

“I genuinely expect this to become the de facto mezzanine compression within the next year,” Rayner said.

Further down the line is the possibility that some production facilities may add 8K video capability. The only way to handle uncompressed 8K video data today is to split it into four 12G feeds, as the bandwidth is far beyond what a copper network can carry on a single cable. JPEG XS might be the lubricant that eases 8K production tools into high-end facilities.

LOS ANGELES—I’m sure you’ve heard about how everything is going IP e.g., Internet of everything. Even live (real-time) video signals are going IP. Sure, SMPTE 2022 has been around for a while and gee, IP switches that can do 10 or 25 Gbps are available, with 40 Gbps just around the corner, so why not? Isn’t this the smart choice?

So I thought, let’s compare the two technologies. For now, I’ll frame this discussion based on 3 Gbps SDI and 10 Gbps IP switches. First, I’d like to describe what a traditional SDI router is designed to do:

• Deliver serial digital input signals, one per input port to one or more output ports;
• Provide consistent delay and performance, no matter how many active signals are being routed and switched; 
• Provide deterministic switch times.
  

Now what is an IP switch designed to do:

• Manage multiple input and output ports;
• Keep track of all routing table entries (network status);
• Process or sort IP data packets and deliver to appropriate next routes.
  

So it seems these are two devices have differing use cases. Yes, in fact, the technology and protocols for each were developed for different use cases and thus have evolved as a best fit for the applications intended.

So why try to put a square peg in a round hole? Proponents of video-over-IP will say that commercial-off-the-shelf hardware reduces overall costs. They’ll also say that IP technology is the prevalent technology in general use, thus more R&D results in more innovation and future improvements. It’s also available from many large and small manufacturers, and offers flexible design of large switch fabrics.

Not to refute these points—as they are true—the key question is what should we be skeptical of? If major industries, including manufacturing, transportation, telecommunications, commerce and banking, have adopted IP, why not real-time video production?

TALE OF THE TAPE: BANDWIDTH
Let’s tell the tale of the tape. The first tale of the tape I’d like to address is bandwidth. Not just the port bandwidth or the internal processing bandwidth, but the total aggregate bandwidth (TAB) of each solution. For SDI, it’s fairly simple:

TAB = (No. of Input Ports) x (No. of Output Ports) x port bandwidth

As an example, a typical large plant video router is now a 1024 x 1024 3G SDI router with a TAB of 3.15 Pbps. That’s 3.15 million Gbps. This bandwidth is available, on command, finite and deterministic.

Of course, not all of these Gbps are in use all the time. In fact much of the time, the video signals maybe color bars! But when called for, there is never a delay or limit to any input going to any output.

From the IP side, bandwidth is a bit more difficult to calculate. What is typically specified in an IP switch is the “line rate;” that is, the physical interface maximum data bandwidth that can be either input or output from the port or ports. But this doesn’t give us the TAB or throughput of the switch. There are many factors that go into the throughput of an IP switch, such as backplane bandwidth, processing speed, buffering and to an extent, the power supply.

One major IP switch vendor’s specification for a large enterprise IP switch—16 slots, 10 Gbps per slot—can handle a maximum aggregate processing bandwidth of 320 Gbps. Each slot can be equipped with different line cards, but for our discussion, let’s assume a 4-port 10 Gb Ethernet card. So we have the possibility of a 64x64 (4x16x2) video switch, with a TAB of 320 Gbps. This works out to just under 3 Gbps per port, input or output. By the way, this switch occupies 7 RU with a maximum power consumption around 4.5 kW.

For comparison, a SDI 3 Gbps 64x64 router fits in a 4U frame, consumes 0.25kW and has a TAB of 12.3 Tbps.

So far, it seems SDI is a better value in terms of TAB, power and size.

(Continued in “SDI vs. IP: Packet to Packet.”)