Wireless all- In-One for Dummies- P14

Wireless all- In-One for Dummies- P14:I still remember when I got my first cordless phone. Suddenly, I didn’thave to run to the kitchen when the phone rang, I just carried the phonewith me. I could make a phone call from wherever I was. Wireless meantfreedom, and this is just a phone that I’m talking about!
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Wireless all- In-One for Dummies- P14 Chapter 3: Networking Your Television: From PC to HDTV In This Chapter ✓ Understanding PC video formats ✓ Maximizing your viewing experience ✓ Digital Media Adapters: Getting video from the PC to your HDTV ✓ Game consoles for watching PC video S treaming video over wireless networks is much more challenging than audio. Even full CD audio only pushes 176KB (that’s kilobytes) per second — hardly enough to challenge even an old 802.11b network in home environments. Newer 802.11g or 802.11b networks can handle multiple users and multiple CD-quality audio streams. Video is another beast entirely. DVD-quality video, which is already com- pressed with the lossy MPEG-2 codec, can consume as much as 9.8MB, or over 1.2MB. If you’re thinking about streaming high-definition video, you’re looking at bit rates that can approach 20 Mbps. Some pristine, well-mas- tered Blu-ray discs approach 40 Mbps. Then there’s the issue of quality of service. Quality of service, or QoS, is a nebulous term that tries to capture the idea that your video should look good. If you’ve ever watched a video streamed from the Internet, and noticed lots of interruptions or breakups in the picture, that’s poor quality of service. All the bandwidth in the world isn’t useful if your video stream keeps getting interrupted. Modern wireless routers and streaming applica- tions are built to try to maintain a high level of QoS. In this chapter, I show you how to maximize your viewing enjoyment while streaming video captured on your PC to your living room over your net- work. You find out about video formats, how to enhance your PC to maxi- mize throughput, and examine a couple of sample scenarios using existing hardware.Understanding PC Video Formats As with audio, video is captured and stored on your PC in multiple different formats. My goal is not to exhaustively cover all possible formats, but to370 Using a PC to Maximize Your Viewing Experience explain the basic concepts in the context of getting that video from your PC to your home entertainment center. In the old, pre-digital TV days, television was broadcast in purely analog formats. If you wanted to record and store an analog TV signal on your PC, it needed to be digitized. A number of different encoding methods emerged to convert the analog TV signal to digital format. The key commonality is that all of these formats used some form of compression — usually lossy compression, which meant some of the data was actually discarded. Techniques such as MPEG-1, MPEG-2, WMV, and H.264 can predict what the pixel will look like five frames after the current one is displayed, so don’t try to save the pixels in the four intervening frames. What this actually means is that lossy compression can help reduce the bandwidth needed to stream video. Unfortunately, HDTV streams are already heavily compressed. A typical over-the-air high-definition broadcast can hit 20 Mbps. A cable or satellite HD stream ranges from 5 to 13 Mbps. Windows Media Center in Windows Vista and Windows 7 can capture high- definition broadcasts using PC capable tuners. If you want to capture digital cable TV shows, you need a tuner capable of ClearQAM capture. Those shows need to be unencrypted. There are PC models built with Windows Vista that can use CableCard to capture premium shows which are encrypted by the cable TV provider. But you have to buy those PCs as a unit — you can’t add CableCard support to an existing PC. Of course, you won’t want to simply watch TV shows streamed from your PC. While the PC can work perfectly well as a DVR (digital video recorder), it’s more interesting to use the PC to store and show videos you, your family, and friends have shot using digital and high-definition camcorders. However you get the video into your PC, the tricky part is streaming it from your PC to your family room.Using a PC to Maximize Your Viewing Experience Before diving into how to display the video streamed from the PC to the home entertainment system, I need to talk about the PC that will be deliver- ing the video. Using a PC to Maximize Your Viewing Experience 371People often just take whatever PC is handy — the home office PC, theirlaptop — and try to stream video to the TV from a general purpose PC. Theresult is often choppy video with strange compression artifacts. Now, youdon’t need a dedicated video server. Your home office PC might be goodenough, but you’ll need to tweak it a bit for best delivery of video content.Here’s a brief rundown on common digital video formats: ✦ MPEG (including MPEG-1, MPEG-2, and MPEG-4): Developed by the Motion Pictures Expert Group, the various MPEG formats are perhaps the most common encoding scheme. DVDs use MPEG-2; some Blu-ray discs are encoded in MPEG-4. Satellite and cable TV often deliver their video in MPEG-4 format. ✦ WMV (Windows Media Video): Microsoft’s proprietary video compres- sion format. ✦ H.264: This is a variant of MPEG-4, used in some Blu-ray movies and online video. ✦ AVCHD: This format is common to high-definition camcorders and is actually one form of H.264/MPEG-4. ✦ DiVX: This compression format is most commonly used on the Web, so if you download videos from the Web to your PC, they may be DiVX encoded. Book VII ...