miércoles, 3 de noviembre de 2010

1000 cables para transmitir HD de forma inalámbrica…

Curioso kit de Asus, revisado en esta nota, que pretende eliminar los cables, de las transmisiones de video HD… Claramente, un ejemplo de “El remedio es peor que la enfermedad”

Asus WiCast: Wireless 1080p to your TV

by Dustin Sklavos on 11/1/2010 12:01:00 AM

The ASUS WiCast

Since it landed, Intel's Wireless Display (WiDi) technology has been something of a mixed bag. There's a lot to mull over: you have to consider latency, the 720p limitation, being stuck with Intel HD graphics, buying the wireless box for your television, and maybe the biggest question of all, whether or not it's really practical. WiDi has resulted in a split decision here; Vivek is a big fan of it, but I have a hard time understanding why someone would deal with all these limitations instead of just plugging in a five dollar HDMI cable and calling it a day.

If we take practicality off the table and focus on the technology itself, we're still left with some frustrating limitations, and mercifully it's those limitations that ASUS seeks to ameliorate with their new WiCast setup. ASUS promises near-invisible latency, full 1080p video, and compatibility with anything that has an HDMI port. We received the WiCast as part of a review kit including two notebooks, but we felt it was worth reviewing on its own.

The setup is probably the biggest hurdle for the WiCast, because when you open the box you're greeted by a remarkable number of little pieces of hardware. There are the two WiCast boxes—the transmitter and the receiver—followed by two HDMI cables (one three inches long, which may be used either at the receiver or transmitter side), two AC adaptors, and a USB cable. At least there are no software discs and a fairly thin instruction manual.

The transmitter and receiver boxes are fairly similar; the transmitter's just the smaller one, but both have an AC adaptor, HDMI, and mini-USB ports. On the receiver the mini-USB port is covered, but it can be used to power the receiver if for some odd reason that's more convenient than just plugging it in. I'm going to assume your television is stationary, though, which means there's a reasonably close power outlet. For the receiver, though, the USB is probably going to be your preferred way to power the transmitter. Mercifully that means that the second AC adaptor isn't essential, but is just an alternative power source if your USB ports are all used up on your notebook/desktop/whatever.

That's honestly pretty much it, too. Connecting everything is fairly self-explanatory, and once you have your HDMI cables plugged in you're just about set. It's one of the nice things about WiCast compared to Intel's WiDi: there's no software to install or configure, and no hardware limitations outside of the HDMI port. That makes for a concise review, though: it either works or it doesn't. So let's see if that's the case.

WiCast in Practice

Getting the ASUS WiCast to work really is a breeze. The manual notes the transmitter and receiver may take as much as a minute to sync, but my experience was much better. With the two boxes about five feet apart, syncing was actually very quick once Windows loaded, and within Windows the solution was as transparent as it should be. The WiCast-connected monitor appeared the way any wired monitor would, and I was able to switch audio over to the WiCast easily.

My first test was to see if the WiCast could hit 1080p, and sure enough it could. Latency, at least on the Windows desktop, was invisible. At 1080p (60Hz), the solution was largely seamless. In fact the only artifacting I really saw was in high-contrast areas, where there would be slight flickering on the edges of shapes and letters. The whole image appeared slightly darker than it did on a wired connection.

The next step was to see how well it handled audio, so I fired up WinAMP and put my usual audio testing whipping boy, The Prodigy's "Spitfire", through its paces. Audio quality between wired HDMI and the WiCast was indistinguishable, though it did serve to highlight how poor the speakers in my television are. It's reasonable to assume the WiCast probably handles multichannel audio perfectly fine, but I have a hard time imagining a home theatre enthusiast who would opt to use the WiCast instead of a hard line for reasons that will become clear soon enough.

For me, the big test was latency, something Intel's WiDi has a real problem with. I fired up Quake Wars (yes, some of us still play this), set it to 1080p, and was up and running. Gameplay was nigh-indistinguishable from a wired connection. ASUS advertises a latency at or below 1ms and while I can't confirm that, I can tell you that from a gaming perspective the WiCast is remarkably fluid and responsive. It's worth noting that this is one area where the WiDi simply can't compete: while I was able to use the ATI Mobility Radeon HD 4650 in my notebook to push polygons in Quake Wars, WiDi is restricted to Intel HD graphics only. So in this test we've already exposed two things WiCast can do that WiDi can't: game, and game at 1080p.

Finally I wanted to test Blu-ray playback, and it was here that things started to get a little hairy. There weren't any HDCP issues, but when I tried to play Iron Man 2, the WiCast started to have trouble with interference. It wasn't anything game-breaking, but there were five horizontal lines of artifacting on the screen, evenly spaced. Adjusting the transmitter seemed to help a little, and often the lines would go away on their own, but nonetheless the WiCast seemed to have a hard time keeping a clean signal at just five feet away.

With the above in mind, we did some additional testing of the signal quality at five foot intervals. Keeping in mind the WiCast is rated at "up to" 33 feet, we were unimpressed with the amount of blocking and other artifacts even at close range with Blu-ray, and it quickly gets worse as we move away from the receiver. Oddly enough, we had better experience testing the WiCast with a Gateway ID49C than we did with a Dell Studio 17—the former worked at up to 20 feet without any noticeable problems while the latter had periodic issues even when the receiver/transmitter were nearly on top of each other.

The signal ended up being more of a case of all or nothing: it either worked or it didn't, though sometimes other factors seem to come into play (a person moving in between the transmitter and receiver, or interference from other electronic devices). Since the WiCast is also device agnostic, you can use it with a PlayStation 3, Xbox360, or any other HDMI-equipped hardware. Again, the most likely use seems to be laptops, simply because anything else is already hard-wired for AC power. Also worth noting is that we measured power draw on the transmitter of 5.7-5.8W, which means if you're running off a notebook's battery, you'll take a pretty significant hit to battery life.

Conclusion: Lots of Wires for "Wireless"

If we take practicality out of the equation, we're left with a solution that is more or less directly superior to Intel's WiDi. That's not too outlandish to consider; WiDi uses a notebook's internal wireless connection, which means it has a peak throughput of 300Mbps. Compare that to the ASUS WiCast's advertised 3Gbps connection and it's obvious why the WiCast is capable of handling 1080p video, multichannel audio, and doing all of that with near-invisible latency. Even better, WiCast works with anything with an HDMI port, while WiDi is limited to Intel HD graphics and Intel wireless hardware.

The problem is we can't take practicality out of the equation, not really. WiDi's big advantage is that it doesn't require an extra box on the notebook side, but the trade-offs are horrendous. In the meantime, WiCast requires you to connect three cables (two USB and an HDMI) to your notebook (or an AC adapter in place of the USB) and a receiver box to your television. The receiver isn't the issue, but the box and cables on the notebook can turn into a mess in a hurry. You're making an awful lot of sacrifices just to transmit 1080p video wirelessly to your television, and given the number of connections that need to be made, that "wireless" part almost feels like a bit of a misnomer.

Range and interference are a concern as well. Five feet isn't an unreasonable request to make for a wireless home theatre or presentation technology, but the WiCast sometimes had problems with interference even at that distance. There weren't any signal drops, but the lines of artifacting that appeared in the picture during Iron Man 2weren't exactly easy to ignore.

This all circles back to the essential problem with wireless display technologies, at least at the present time: it's a hell of a lot of work just to get rid of one cable connection. For WiDi, I have to hunt down a notebook with the specific configuration needed to use it, and then drop $99 on the receiver box for the television. For the ASUS WiCast, I have to pay $199, but at least it'll work with whatever I need it to work with. Or I can just order a fifteen foot HDMI cable off of NewEgg for under ten bucks and not have to worry about latency or interference.

So that in mind, I will say this: as far as wireless display goes, the WiCast is in my opinion a superior solution to Intel's WiDi. If this is something you have a need or a use for, then it's an easy sell. But for everyone else, this technology is a tough sell from any vendor. It's just too cumbersome and asks too many trade-offs just to replace one of the cheapest wired connections in a home theater. Yes, you can use it with desktops and even PS3/Xbox 360 if you'd like, but as long as you're still running an AC adapter and range is realistically less than 10 feet, we can't really see this as anything but a niche product. Some will love it, and it's much cheaper than previous 1080p wireless solutions, but $200 is still a fair amount to spend unless this fills a specific need.

 

Fuente: http://www.anandtech.com/show/3978/asus-wicast-wireless-1080p-to-your-tv

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