Digital video quality is all about bit rates. In general, the higher the throughput--whether for streaming clips from the Web or for zapping TV around the house--the better the result. So if picture quality is important to you, don't hesitate to upgrade the network that will transport all those images.
If all you want to do is watch YouTube videos or the current generation of iTunes video downloads (which are standard-definition), even a good 802.11g Wi-Fi router should have no problem with bit rates up to about 5 mbps. Of course, this rate doesn't come close to matching the quality youd expect from DVDs or cable TV, especially if you have an HDTV.
Commercial DVDs use MPEG-2 compression at peak bit rates of around 10 mbps (and averaging half that). HDV camcorders typically have peak recording rates of 19 mbps for 720p, or 25 mbps for 1080i, using a high-definition form of MPEG-2. To stream these, you'll need a draft-802.11n or MIMO router. A draft-802.11n router will provide you the speed and range to support high-bit-rate video (we got real-world throughput of over 50 mbps in our tests; Wireless Routers: The Truth About Superfast Draft-N); and special quality-of-service (QoS) algorithms in the routers give priority to streaming media data packets over, say, downloading the latest Windows OS updates. You'll also need to buy matching draft-802.11n adapters for all the devices you want to stream video to or from (or you'll need to connect them by wired ethernet). The Wi-Fi Multimedia standard, also known as 802.11e QoS, must be supported on both ends of the connection, too; the product's box should state whether it supports this standard.
Now that you have the plumbing down, here are a few more tips:
- Use the highest-quality connections possible between your computer or media server and your TV. In order from best to worst, they are as follows: HDMI or DVI, component, S-Video, and composite. Having high-def 720p video on your media server won't do you any good if your home theater relies on a composite connection. You can buy a device such as D-Link's DSM-520 Wireless HD Media Player with HDMI for about $240 online.
- When compressing your own home movies for streaming, find the highest playback quality that your setup will support. Do some test transfers to find the best combination of compression and frame rate. Typically, MPEG-4 or H.264 will be the best choices.
- For viewing your home TV remotely via Sling Media's Slingbox or Sony's LocationFree, make sure that your broadband Internet connection has an adequate upload speed. DSL and cable modems are typically asymmetric. A 3-mbps download speed may be matched with a 400-kbps upload speed, which will limit your video quality. You can check your upload speed at www.speedtest.net. We recommend a threashold upload rate of 600 kbps for reasonably smooth remote Slingbox viewing in a medium-size video window. On a local network, our Slingbox slings at between 1 mbps and 2 mbps--good enough for full-screen viewing.
This story, "Better Streaming Video" was originally published by PCWorld.