HD Should Be Wired, For Now

AcidAUS writes "Current wireless networking standards aren't fit for streaming high-definition (HD) content between a media centre PC and multiple extender devices, according to Intel and Microsoft." From the article: "'You've also got to remember though that wired connectivity is a lot more efficient than when you start putting it [HD content] over wireless,' said O'Shea, adding that the real-world bandwidth of 802.11g would 'probably top out around 22Mbps'. Intel's Gurgen added that in addition to efficiency differences, one must also consider other network traffic when weighing up a move to wireless. 'Remember that at that one time when you're streaming content it's probably not the only thing that's happening. You could be sending e-mails, you could be downloading some sort of update,' said Gurgen. Both O'Shea and Gurgen declined to comment on whether or not the upcoming 802.11n Wi-Fi standard would make wireless streaming of HD content throughout the home viable."

Re:EM Pollution

[Anonymous Coward]

You are wrong [wikipedia.org]. However IEEE 802.3af only provides max 19.2 watts of power, that is too little for many applications.

Re:What a load of crap...

[alexhs]

Your parent post lacked that detail, but Freebox uses MiMo technology, an implementation of draft 802.11n. So it has more bandwith that regular 802.11g.
AFAIK they're also using MPEG4, which is more space efficient than MPEG2 (and I get a little less than 4Mb/s for non HDTV streams - currently no idea for HDTV streams, I lack an HDMI wire)

Re:What a load of crap...

[Anonymous Coward]

What company are you a sysadmin at? "My Mom's Basement Incorporated"?

That 22mbps number is based on real world testing. I personally have never seen 802.11g go above 25mbps - and that was with a Cisco AP and an Intel wireles adapter two feet from eachother. I'd sure like to know what kind of 802.11g AP and wireless card you are using to get 40mbps throughput.

As for wired, it impossible to get 100bits of throughput on a 100mbit link due to overhead. Under optimal conditions, you can get 85-90mbps.

Re:What a load of crap...

[Gobelet]

In France, but in Europe globally, transmission of HDTV is made in H.264. And it's mandatory. So Free is streaming MPEG-4 HDTV content over Wi-Fi, at something like 5 or 6 Mbps. And the quality is just... wow.

Re:welcome to...

[megaditto]

Well, 100 baseT is inadequate for streaming good video.

Assume no compression (i.e. good video) 800x600 pixels, 32 bits/pxl, 30 fps

Moving that data alone requires 500 Mbps, not counting protocol overhead. Of course, with compression you can easily cut that down by a factor of 10, but that will be lossy.

Re:What a load of crap...

[Fred_A]

I use Free as an ISP too (although I have the previous generation of their Freebox modem which is just a single box). FWIW though, the HD TV content is roughly of DVD resolution. You can play it either through your TV or with VLC (or both). So it's not TVHD in the usual commercial sense although it's much better than "regular" PAL/SECAM TV. And the compression quality is quite good.

Oh and the "modem" actually is a little Linux embedded computer. :)

The way the local market works is that Free often is the one that innovates with the other ISPs quickly offering similar packages. In the end everybody wins I guess. So ADSL 2+ broadband is roughly 30€ whatever your ISP is. Including TV and international phone.

Re:welcome to...

[kryptkpr]

Video is due to it's very nature very redunant. The majority of the content which was in frame X is still there in frame X+1 and frame X+2, it may have just moved a little. Good compression (MPEG4 at a high data rate) simply takes advantage of this, and will not be noticable to the viewer while still reducing the data rate 3-5x.

Now as to your assumptions. First, why 32bpp? You don't broadcast an alpha channel. 24bpp is enough for RGB, and 16bpp is enough for YCbCr (using 422 sampling, which is fine for video but not so great for computer images).

Second, 800x600 isn't HD. The minimum resolution to be called HD is 720p, which is 1280x720 (roughly a 1 megapixel image). Some folks will try to pass 480p off as HD, but it's not, it's ED.

So taking a typical movie in HD, that's 1280 * 720 * 16 bpp * 30 fps * 1/4 (compression gains) = 110 Mbps. Still a little too much for fast ethernet, but GigE could support several such streams without a problem.