By Prince McLean

Published: 08:00 AM EST

Sling Media's release of its SlingPlayer Mobile application for the iPhone and iPod touch early this morning will give Sling enthusiasts a new way to watch their home TV signals remotely from nearly anywhere, but some significant limitations in the app are likely to dampen some users' initial enthusiasm.

Sling specializes in video placeshifting, which takes audio and video inputs from either a cable, satellite, or antenna feed or the output from other video devices such as a DVR, DVD player, or Apple TV, and encodes the signal using a Slingbox for Internet distribution to computers or mobile devices running the SlingPlayer application.

Sending a remote video signal requires a fast Internet connection, and in particular a fast outgoing connection, as the SlingBox needs to push a compressed video feed out over the Internet to the remote location you hope to watch it from. However, most consumer broadband Internet accounts are designed around web browsing and consumption of inbound server-side content, meaning that they deliver far faster downloads than uploads.

DSL commonly offers 0.768 to 1.5 megabit downloads, but often as little as 0.128 uploads, while "fast cable Internet" may deliver as much as 8 or 16 megabit downloads to customers in developed areas of the US, but only a quarter or less than in upload bandwidth. Even customers reporting 50 megabit or greater downloads commonly report only getting ten to twenty percent of that speed for uploads.

That's the problem facing all server-type consumer applications like the one offered by Sling Media. Even customers who have fast Internet access both at home and in their vacation spot's hotel, college campus, or workplace will be hampered by the weakest link: the relatively slow upload service offered by most ISPs serving home users. Sling addresses this issue by applying proprietary compression and optimized signaling to deliver the most efficient transmission possible.

As Internet speeds slowly improve in the US, Sling's efficiency has enabled the company to branch out into mobile devices. In addition to the Windows and Mac OS X client software it includes with its SlingBox hardware, the company offers a separately priced mobile client for certain Symbian 9.1 phones, several modern BlackBerry smartphones, a variety of Windows Mobile Pocket PC and Windows Smartphone devices, and a beta PalmOS client that works on three recent models.

Conspicuously missing from its roster of supported mobile devices has been the iPhone; that is, up until an announcement in January demonstrated a new Cocoa Touch version of the SlingPlayer Mobile software for iPhone and iPod touch devices. That product is now available for the same price as other mobile phones, although at $29.99, the price of the iPhone app might shock App Store customers more accustomed to buying $2 games and $5 utilities.

Introducing the Slingbox

To test out the new iPhone app (App Store, $29.99), Sling shipped us its top of the line, $299.99 Slingbox PRO HD. Configuring a new SlingBox is quite simple, although not quite an Apple experience. It does, however, ship with pretty much all the cables you'll need, which is more than can often be said for new Apple gear.

The Slingbox PRO HD box accepts a single cable input as well as two auxiliary video inputs: one via standard composite or S-Video cables and a second supporting HD-quality video over component cables. The box then connects to your TV using either standard definition composite or HD-capable component cables, as well as passing through the cable feed. For audio, the device supports both standard stereo input as well as higher quality S/PDIF coax audio. It seems odd that the Slingbox does not support HDMI and digital optical audio connectors, and that it can only manage one antenna and two other inputs. The $179.99 Slingbox Solo model only works with a single input.



The Slingbox also provides an IR blaster cable with several outputs, which is used to allow the device to emulate a remote control. This enables a remote user to change the channel or navigate through the menus of nearly any device a user might want to plug in, although this can be an arduous process due to the delays encountered when working remotely.

The SlingPlayer software for the Mac or Windows enables users to then switch between the connected devices, change channels, fast forward through content when supported, and watch essentially anything they could watch from their living room on their laptop while traveling. The biggest limitation on the current Mac version is that it only supports viewing standard definition signals, but the Windows version also has an hour buffer that allows users to fast forward and rewind through the stream like a DVR allows, and also presents a programming guide missing from the Mac version.

By default, the player software puts your video feed in a small window and presents a virtual remote control, so the benefit of HD video isn't noticeable. However, if you want to blow up your signal to watch full screen using your notebook as a virtual TV, the SD image you get on the Mac isn't exceptional. It's also not terrible. Sling says they're working to deliver HD support for Mac users, and the latest version of the new Mac desktop software Sling Media just delivered promises to improve video playback quality.



The new iPhone app offers most of the same features to Slingbox users right from their mobile phone. To match signal quality to the bandwidth a user has available to them, both desktop and the mobile versions of the software enable standard or higher quality settings for audio and video. With an optimal connection, the iPhone app delivers pretty decent watchability and fairly good quality audio.

We tried a prerelease version of the app using AT&T's EDGE network, and discovered that despite Sling's best efforts, EDGE just isn't fast enough to support decent playback. It was impossible to get more than five to ten seconds of terrible quality video before the system fell back to a spinning cursor promising to optimize the signal quality, which typically took as long as the next five seconds of attempted video, then popped up again. Using AT&T's 3G network, which we managed to find in a few pockets here and there in San Francisco, we could actually maintain a pretty good video signal.

Slingplayer Mobile WiFi Only

End users won't be able to similarly experiment themselves, however, because Sling's iPhone app has been barred from supporting mobile networks as part of the App Store demand that developers not consume significant network resources from their apps. That means the iPhone won't be able to access Sling feeds anywhere other than the WiFi hotspots supported by the iPod touch.

That's a disappointment to iPhone users, but likely a relief to AT&T, which has been desperately scraping together the resources to support the bandwidth-heavy apps that iPhone users are already hammering its network with, primarily Mobile Safari and to a lesser extent, YouTube, Mail, and the iPhone's own iTunes and App Store. A recent report bewailing the bandwidth use of the iPhone on AT&T's mobile network recommended that all mobile service providers cut smartphone users off from iPhone-style unlimited data service entirely to protect their profits.

While that's completely farcical, it does underline why AT&T, already pressured by Apple to support the demands levied by the iPhone's bundled apps, is so adamant about limiting users from opening up new network-frying services at a time when the company is struggling to provide good call quality and, on good days in lucky neighborhoods, reliably fast data service for the iPhone customers it loves to collect revenues from.

That reality isn't going to help out users irritated by the assumption that Sling Media's original plans to support viewing over 3G would pan out; Sling hoped to support 3G (and even EDGE) right up to the end in its negotiations with Apple. Regardless, mobile users who are fans of the Slingbox will now have another reason to eye some of the phones offered by providers that do support SlingMedia's mobile app over their 3G EVDO or UMTS networks, including a couple models that are... sold by AT&T. Of course, those other phones don't have the same massive network effect as the iPhone.

At the same time, a variety of the other phones Sling supports also only work over WiFi, such as every BlackBerry model outside of the Storm offered by AT&T. All of the supported Curve, Pearl, and Flip models, whether offered by AT&T, T-Mobile, or Sprint, all only work with the SlingPlayer Mobile app over WiFi. A large number of older and newer BlackBerry phones are not supported at all, lending some relief to those wondering if living inside Apple's big tent is worth it. Navigation and basic usability on the BlackBerry (below) is also decidedly worse than the iPhone version.



Similarly, while a couple dozen Pocket PC models officially support mobile network viewing with the appropriate SlingPlayer Mobile app, only around half of the 14 supported Windows Mobile Smartphone devices will work outside of a WiFi connection, and Sling warns about poor performance when using the Motorola Q8hxx series or Samsung BlackJack II over 3G. Sling also only recommends using its mobile app on nine different Symbian models, and more than half of those only support WiFi viewing. As with Sling's other mobile offerings, the Symbian version only presents a small video area surrounded by lots of buttons that clutter up the screen (below), while the iPhone version devotes the entire screen to video playback and menus disappear when not in use.



With the weird assortment of incompatible phone models and splintered platforms out there, it's no wonder why mobile developers are flocking to Apple's platform, which actually delivers a coherent platform of users who actually buy mobile apps. It's certainly no secret that other phone platforms are chaotic and dysfunctional, but Sling Media's offerings provide a case study into how difficult it actually is to support a basic video playing app across more than a handful of specific phone models on each of the existing mobile platforms in the smartphone arena.

On page 2 of 3: Using Slingplayer Mobile on the iPhone; Using Slingplayer Mobile for TV viewing; and Using Slingplayer Mobile with Apple TV.