Let's say you have a set of videos on your hard drive that you want to play on your TV. Maybe they're home videos of your child's soccer team, or maybe you downloaded every single episode of Mad Men via BitTorrent, we're not here to judge.
The point is, you want to watch these videos on the HDTV in your living room, not on the PC in your office. Here's how to do it quickly and easily. Depending on your home theater setup, you'll either directly connect your PC to your TV, stream the videos over your home network, or use your TV's ports to attach a storage device.
Plug your PC directly into the TV
If you have a laptop or a small PC, you can just plug it directly into your TV. That way, you won't have to buy any new equipment (except for a cable or two), you won't need to deal with codec or networking hassles, and you can use whatever applications you like.
The type of connector your TV requires will depend largely on how new the TV is. HDMI is ideal, since you need just one plug for HD video and audio, but you can also use VGA (or DVI) with an inexpensive 3.5mm-to-RCA audio cable.
If your TV doesn't have HDMI or VGA, things get trickier. Your only option for HD video is component video, but not all PC video cards support component output without a converter. You might be able to use an S-Video port (1024x768 resolution), but you're probably better off looking for another option.
Use your TV's USB ports or SD Card slots
Newer TVs typically come with a USB port or an SD Card slot, so you can plug in a USB drive or memory card and view your photos, listen to music and watch movies. Often, however, such features are designed with digital cameras in mind, and they may not always support the file formats and media codecs you need to watch TV. You can find out what formats your TV supports in the specs listing or user manual.
The Sony KDL-55HX800 TV, for example, supports video in AVCHD (a format used heavily in HD camcorders), MP4 and MPEG-1, while the Panasonic TC-P42G25 lists support for only AVCHD and MPEG-2 videos. Odds are, your downloaded videos aren't going to be in those formats; most TV shows are encoded with the x264 or XviD codecs, which you won't find on these TVs.
The Samsung UN40C7000, on the other hand, supports a veritable bonanza of common codecs, including Divx, XviD, MPEG-4 and H.264. But if you're particularly unlucky, you might own a TV that doesn't officially support media playback yet, the Vizio XVT553SV for example has three USB ports but requires a not-yet-released firmware update to support playing media via USB.
Set up a UPnP server to stream over your network
If you can't move your PC into your living room, you might be able to use your home network to stream video to your HDTV with minimal fuss. To do that, you'll need a UPnP (Universal Plug and Play) media-server app for your PC and a way to connect your TV to the network (either via built-in Wi-Fi/ethernet or through a separate set top box).
Not only can you leave your PC at your desk, but you can also avoid worrying about codec problems or video file format support, UPnP server apps handle the video decoding on your PC, so adding support for new video formats is much easier.
Keep in mind that if you're streaming lots of HD video, you'll probably need to stick to a wired network. Wi-Fi is prone to dropped frames and buffering delays, but if all your devices are on 802.11n Wi-Fi, you might be able to get away with it.
To set everything up, first you'll need to connect your TV to your network. Newer TVs usually have an ethernet port or a Wi-Fi adapter that lets you access Internet-connected functions as well as local media. If your TV can't connect to your network, you'll need to hook it up to something that can, either a set top box such as a Roku or an Apple TV or a modern game console (Xbox 360 or Sony PlayStation 3), will work fine. What you're looking for is a device that supports "UPnP media streaming", if the specs say "DLNA Certified" even better.
Next, you'll need an app for your PC that can share the video across the network. Windows 7 supports this function out of the box, just search for "media streaming options" from the Start menu.
From there, you can select which devices on your network you want to allow to access your media, set sharing options based on how you've rated each song or movie, and more. Once you've configured things, you should be able to access all your media from your TV via your set top box of choice.
Unfortunately, Windows 7's built-in media sharing doesn't always work as well as it should. I found that with certain set top boxes, a DVD rip or 720p TV capture that looked excellent on my PC would typically look pixelated and heavily artifacted when I used Windows 7's media function. Also, for some reason not all of my videos, shared folders or library contents showed up when I used Windows media sharing.
Instead, I opted for the PS3 Media Server app (PC/Mac/Linux), which, despite the name, worked just fine with my Xbox 360 and various set top boxes. Not only is it free and easy to set up, but it also supports transcoding, a feature that lets your PC convert your audio and video to a different format as you're watching it, in case your streaming device doesn't support the codec your media uses.
Just download, install, and launch PS3 Media Server, and click the Navigation/Share Settings tab. At the bottom of the window you'll see an icon with a folder and a large green "+" on it. Click it, select the folder(s) you wish to share, click Save at the top, and click Restart HTTP server.
Once PS3 Media Server is finished reloading, you should be able to access your media from your set-top box or TV's media-sharing menus.
If you own a network-attached storage drive or a router with a USB port, such as the Belkin Play Max, you may not even need to use a PC to host your videos, the device might have a built-in UPnP server setting. In that case, all you would have to do is configure it using the included software and copy the videos over to the NAS drive (or plug a USB drive into the router's USB port).