About Switched Broadcast Video: Don’t Look Now, It’s Back!
by Leslie Ellis // July 26 2004
Funny how things come back around again. It’s no secret that cable providers are examining ways to make better use of the bandwidth surging through their $70 billion pipes — without ever having to revisit a backhoe.
At least six techniques are underway: There’s “all digital/less analog,” which Charter Communications Inc. put on the map with its digital simulcast effort in Long Beach, Calif.
(Aside: It came through loud and clear at last week’s Cable & Telecommunications Association for Marketing Summit that “all-digital” almost certainly won’t happen for decades, which probably makes “all-digital” a misnomer. “Not no analog” was suggested, as in “all-digital is not equal to no analog,” but that’s too grammatically clumsy for sober conversation. Marketers, have at it.)
Then, there are bandwidth extensions, at least to 860-MHz. And there’s optical resegmenting of plant, to lower the number of people sharing bandwidth legs. Advanced forms of modulation and codecs often wind up on the “bandwidth options” list. That’s four.
Fifth are the better methods to “groom” digital traffic onto carriers, known in the lingo as “statistical multiplexing,” or “stat-muxing,” for short. The vendor community often calls it “rate-shaping,” too.
The sixth is the subject of this week’s translation: Switched broadcast video. It appears under several labels, like “switched digital video,” or just “switched video,” or “switched digital.”
If you’ve been around since the last time the telcos attempted a video attack, this one may jangle a distant discord. Switched digital video: Wasn’t that the pitiable technical option for people with “bandwidth issues”? (As in, not enough?)
One of the payoffs for taking verbatim notes over the past 15 years is the merriment in reminding people of what they said in prior industrial chapters. The response to switched broadcast from cable’s most distinguished technologists, back in the early to mid 1990s, was amusingly gruff. “Switching video is frivolously expensive!” they harrumphed. “Gold-plated!”
At the time, the essence of those exclamations was true. It was expensive.
Now, thanks to the flourish of Gigabit Ethernet gear to pump more bits faster, it’s not so improbable to picture a switch plunked in near the pump. Instead of sending all channels to the back of the TV set (including the stuff nobody watches), put the lightly-viewed channels into a switching pool. Make passage only when people tune to them.
The space they formerly inhabited, and the bandwidth it represents, suddenly becomes available for other purposes — more VOD, HDTV, or broadband offerings, for example.
By my count, two of the top five MSOs are testing the technologies associated with switched broadcast.
That means a switch, for the headend, to mind things, made by companies like BigBand Networks. There’s also a minor piece of “client” software, for the set-top box.
Neither MSO is ready to go on record with the who, where and what yet. Both agreed to background-elaborate on the “how and why.”
Understanding how video delivery changes with switches starts with knowing how it works without switches.
Say that’s you, there on the couch with the remote. You tune to a lesser-watched program. (Let’s pick on my own esoteric viewing habits, and say it’s Victory Garden, before PBS ruined it.)
Switched world view
Your digital-cable box consults its internal channel map. Say you asked for channel 222. The channel map correlates what frequency and multiplex holds channel 222, “points” to it, converts it from digital to analog (your TV likely needs analog), and sends it to the TV, for display.
In a switched world, perhaps Victory Garden is deemed low enough in viewership to be put on a switch. Still, you tune in. The box consults its channel map, and sees a placeholder: This is a switched channel. Proceed to the headend.
There, the switch assesses the situation: Somebody in service group X wants channel 222. Is anyone else in service group X already watching it? If so, you join that session. If not, the switch readies your stream from its channel pool. It opens up a session, not unlike establishing a VOD stream.
So far, engineers say they like it (big time like it) for two reasons. One, it’s the least expensive of the six options. Two, channel changing happens way faster than with “regular” digital channels. (The latter strikes me as glorious news, as a digital cable customer.)
They don’t like it because it’s the same technology being used by anyone contemplating “IP video,” which means — you guessed it — the telcos.
And, switched broadcast isn’t without a helping of politics. It is, by its nature, dependent upon a two-way network. (How else will that channel map placeholder get up to the switch for handling?)
Anything that isn’t two-way won’t work on a switched broadcast architecture, which includes those digital TVs with the CableCARD slots.
Nonetheless, switched broadcast will likely emerge as an active technology, especially as bandwidth-hungry services, like HDTV, continue to fuel bandwidth efficiency techniques.
Plus, switched video carries attributes that please several constituencies. It doesn’t touch the plant, which makes Wall Street happy. It barely touches the set-top and is comparatively easy to implement, which makes engineers happy. It opens the way for more services, and lets digital customers change channels appreciably faster, which makes marketers happy.
And it’s the cheapest of the alternatives, which makes everybody happy.
This column originally appeared in the Broadband Week section of Multichannel News.
CTAM Preview: Near-Term Technologies
by Leslie Ellis // July 12 2004
On Independence Day, we invited a few friends over for a cookout. Just into the second mojito, a noticeable commotion permeated the scene.
The best way to describe it is “cell phone athletics.” (They called it “mobile personal media.”)
It seemed to be all about snapping a cell phone photo of someone, then picking the perfect cell phone song for that someone. When he or she calls, the picture appears and the song plays. (One guy even recorded short video clips, on his phone, which is why everyone will remain nameless.)
Like so many times, I wondered if I was observing a fad, or if the multimedia trimmings to the common cell phone would prosper.
(In either event, it looks suspiciously like yet another charger cradle for yet another device, to later join the boxful of cradles without devices, all in a big rainy-day tangle in the basement.)
The cookout consensus, among the unequipped of us, was that cell phones seem to shrink in size, and multiply in features, every six months.
Other technologies seem to flourish more slowly. Fireworks come to mind.
The shapes that glimmered onto the night sky later that evening — hearts, stars, even a Saturn-looking thing — combined with the kaleidoscope of color, took me by surprise. Maybe it was a mind trick, but it sure seemed like fireworks have matured beautifully over the past 20 years.
From cell phones to fireworks, a fluctuating pace for technological change is a given. What’s hard is picking which technologies to follow, amid the wide range of motion — usually as a side dish to your regular job, which is probably busy enough.
Such is often the case for the industry’s marketing forces, who meet in Boston next week for the annual Cable & Telecommunications Association for Marketing Summit. Part of their work is to shape how consumers discover and choose new cable services, in an increasingly competitive environment.
That made it seem fitting to devote this week’s column to the near-term technologies aimed at cable customers.
What cable gets
These days, looking ahead necessitates the lumping of new technologies into two types: Those that wind up in your systems, and those that you put there.
So far, the set-top/video connection remains immune to anything other than what you put there.
It’s that cable modem/broadband Internet duct that’s becoming the load-bearing vessel for “outside” stuff that winds up in cable systems.
Near-term, that means more merchandise that looks, to consumers, like phone service.
It comes from companies like AT&T Corp. and Vonage Holdings Inc., among many others. They use a method of communicating known as “SIP,” for “session initiation protocol,” which is largely undetectable by the cable modems underneath.
More such competitive services are coming.
And there’s another biggie in the near-term sites: Home media centers.
They’re big because of what’s behind them, which is at least two big industries: Consumer electronics and personal computing.
Because it’s new turf, with lots of sparkle, the home media center is the epicenter of an unrestrained bit of nomenclature sparring.
The attempts at a name for the technology — residential gateways, media centers, media center PCs — elbow into the attempts at a name for what they provide — networked home, digital home, multimedia home.
Their purpose, in most cases, is to be the central repository and traffic cop linking up all of the digital stuff in a person’s house. That means photos, videos, DVDs, music, and digital video recordings of TV — available to multiple devices, in multiple rooms. Everything gets connected.
What cable’s doing
In both cases — communications services that ride through cable modems, and home media centers — there’s considerable activity on the home turf. That means competing products that can be put into circulation, to vie with the stuff that winds up there.
At least one ranking MSO is quietly testing SIP-based services, for example, while monitoring how AT&T, Vonage, and the others do with theirs.
On the media center front, the traditional set-top suppliers are designing many, if not all, of the features that come with CE- and PC-styled home media centers (think multi-room DVR and HD-VOD here.)
Simultaneously, the technologists working on home networks, wired and wireless, are tackling the issue from the IP (Internet protocol) side of the network.
On all fronts, the main barrier to media centers is known as “digital rights management,” or “DRM.” It’s always within two feet of any conversation about home media centers, sticking up at a pointy angle, demanding resolution.
The problem is how to make a device that copyright holders will deem a “trusted domain,” to hold and share content with other “trusted” devices.
The friends who showed up for the cookout, by example, are gadgetry buffs. It’s fun for them. It’s their job, in a way.
Most of us probably know people who can barely turn their cell phones on, let alone retrieve messages.
Still, this blitz of handheld things to make our digital stuff more portable seems unavoidable. Digital PDAs, cameras, phones, DVD players, MP3 players, and portable DVRs (and their charging apparatus) are way more amongst us than they used to be, even five years ago.
If it works better with broadband, it will show up in cable systems. Ready?
This column originally appeared in the Broadband Week section of Multichannel News.