Let me say before I dive into this that I believe that Apple is waiting for 802.11n to get iTV out the door. If it’s going to have the ability to keep people buying from the iTunes Store, it needs to eventually handle HD content. It’s also going to need to be one of several units in a house.
That said, people are coming down on 802.11g a bit prematurely. I want to break it down from a technical and personal experience standpoint.
First, let’s start with who says that 802.11g just isn’t up to the task of streaming video. There’s our own Dan (who said it on the podcast), Chris Breen, and Daniel Eran. I’ll admit that it was Eran’s comment that really sparked the urge to rebut the idea.
While 802.11g, aka Airport Extreme, is good enough for AirTunes audio streaming, it isn’t really good enough for streaming video. Yes, it can in ideal conditions, but only at very low quality, and not very reliably.
Keep in mind that he has since altered his stance a bit, indicating that the 802.11n is needed for long term viability, a point I agree with. It’s not that necessarily that 802.11g isn’t up to the task of streaming video.
The technical problem with the original argument is that in terms of bandwidth, 802.11g is completely up to the task of streaming video, and good video. The current “near DVD quality” movie content at the iTS can be downloaded in half an hour on a 5 Mbps link. Assuming a 1.5 hour movie, to download in real time, you’d need 1.67 Mbps of bandwidth. 802.11g is 25 Mbps in general usage. Mathematically, that’s way more than enough. Examining the TV shows I just downloaded, it was about a 1 GB for an hour and a half (I apologize for not having an actual movie to check). That works out to 205 Kbps. Clearly, 802.11g is capable. In fact, based upon a 3-10 Mbps data rate for DVDs, an 802.11g link is capable of streaming pure DVD data.
That leaves the question of why Chris had so much trouble trying to stream compressed DVD data over an 802.11g link. Ultimately, this comes down to implementation of how the streaming protocol is implemented. Wireless connections have a lot of variability in them. If you watch the bandwidth used when saturating a wireless connection, it goes up and down. Furthermore, the latency in transmission is highly variable because of corruption issues with wireless.
The solution to this problem is generally buffering, which Apple either doesn’t do, or isn’t doing very well. By building up a buffer, periods of slow transfer just take data from the buffer faster than it’s being filled. Periods of fast transfer have the opposite effect. They fill the buffer up. The key for this methodology is the size of the buffer. You don’t want a huge one because it means the user will have to wait longer. On the other hand, if it’s too small, you can empty the buffer during slow periods, causing choppiness. If you’ve ever tried streaming movies through iTunes sharing, you can see what happens when you don’t have a buffer (or at least one that’s large enough). Apple needs to make sure the buffering in the iTV is top notch, even with 802.11n. Why it hasn’t been fixed in iTunes sharing, I don’t know.
How do I know that buffering will take care of this? I own an EyeHome. I can stream nearly any kind of data to it over a generic 802.11g link. In fact, even ripped DVDs stream (though, due to EyeHome limitations, audio is only sent to the optical port which I can’t use). It doesn’t miss a beat.
Ultimately, the real problem is that the methods that Apple supplies to stream media are simply inadequate for use on a wireless link. Sure, 802.11g’s speed isn’t the most reliable, but it is adequate given the proper protocol. So let’s stop beating up on it.
I've come around to your way of thinking, Derik. :) I think, as we've discussed, a lot of the problem resides in iTunes/Front Row for video sharing. Playback via them is pretty choppy at times, but if you mount a remote drive and play a video off of it, it seems to work fine.
802.11g is certainly sufficient. Try this: download a movie from the iTunes Store when you're connected via 802.11g and then start playing it while you're downloading. Many users have reported this feature works fine, so obviously the connection is strong enough.
That said, I think the idea that the iTV's being future-proofed is quite believable. Sooner or later, we're going to be seeing HD content on it, hence the HDMI connector. Then again, if the N standard isn't approved by Q1 2007 (and I have reason to believe it may not be), perhaps we might see Apple releasing iTV with 802.11g in it. At least for the first version.
If the initial version is G, I'll likely stay away from it as I can see the utility in an 802.11n version.
My question is, if it has N, will the N versions of Apple's wireless routers debut at the same time? Will they start offering N in all their computers as well?
I decided to playback a TV show from my mac mini (basement) on my macbook (living room) over my 802.11g network using Front Row and the Apple remote. It worked flawlessly. No skipping, no loss of quality, no delays. I am totally impressed.