Friday, October 7, 2011

Gently down the stream

If you have a moderate-to-large iTunes library, you’ll find the Apple TV’s hard drive too cramped to hold much of your content. (See Chris Breen’s video on Exploring Apple TV.) This would be a serious drawback if the device’s streaming capabilities weren’t as good as they are. It can stream video and audio from up to five computers—from both Macs and Windows PCs. Setting up streaming works similarly to syncing. On the Apple TV, choose Sources, and select Connect To New iTunes. A new PIN number will appear. On your computer, enter that number into iTunes by selecting the Apple TV in the iTunes Source list, and you’re connected. Choose that computer as the source within the Source screen on your TV, and you can access the video and audio content in its iTunes library. Note that it can take several minutes for a streamed computer’s content to appear if that computer’s iTunes library contains a lot of media files. For example, the iTunes library on my Mac Pro holds 217GB of data, and it took around three minutes for it to be accessible on the Apple TV over a wireless 802.11n network.

Photos cannot be streamed. Instead, on the computer synced with the Apple TV, iTunes formats the pictures you select (from iPhoto albums or a folder of your choosing) and copies them to the Apple TV’s hard drive. Once on the Apple TV, you can view a selected album or your entire photo library as a slide show. Much like with iPhoto, you can choose from a variety of transitions as well as determine the display time for each picture.

With content purchased from the iTunes Store, video streaming is quite good over 802.11g and 802.11n wireless networks, as well as over wired Ethernet networks. Playback of video files begins in a matter of seconds. When you press the remote’s forward button to fast-forward or skip to the next chapter, there’s a delay of a few seconds while the Apple TV buffers the incoming content—a progress bar shows you how far along in the process it is. Though not nearly as fast as jumping between chapters on a DVD player, skipping ahead on the Apple TV isn’t terribly distracting on a fast network.

If you’ve ripped your own video at high bit rates, streaming can be a bit dicier. Using HandBrake, free software that can convert many commercial, copy-protected DVDs to an unprotected digital file, I ripped House of Flying Daggers at a resolution of 720 by 304, at 24 frames per second, encoded in H.264 format, and with an average data rate of 2,608 Kbps. Over my 802.11n network, with a strong signal streaming from the Mac Pro, the movie briefly froze after playing for about 15 minutes. It did so again a couple of minutes later. I’m not completely surprised because I was pushing a lot of data at the Apple TV, but it’s something to keep in mind if you rip your own movies at high bit rates.

If 802.11b wireless is part of your network, glitches with high bit rate videos will become apparent even more readily. Apple claims that the Apple TV requires an 802.11g or 802.11n wireless network or a wired Ethernet connection to stream video. I was pleased to find that I could successfully stream Pirates of the Caribbean: The Curse of the Black Pearl (a video purchased from the iTunes Store) from an iMac that contains an 802.11b AirPort wireless card over my 802.11n network. The Apple TV fared much worse on this computer with a ripped version of It’s a Mad, Mad, Mad, Mad World encoded as an MPEG-4 movie at a resolution of 720 by 288 and with a total bit rate of 2,391 Kbps. Just eight minutes into the movie, the Apple TV paused and stopped to fill its buffer. It then continued playing, but a minute and a half later, it paused and refilled again. My experience indicates that some video will stream from an 802.11b computer over a fast network, but you’ll encounter far fewer problems if you stick with Apple’s realistic recommendation.

The Apple TV can also stream movie trailers and iTunes Store previews—movies, TV shows, and music. This type of streaming works well too, provided you have a typical DSL or cable broadband connection.

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