Producing Participatory Media
Class 10 - July 31
Topics:Digital TV: A Cringely Crash Course
Television in transition
High Definition Television: HD is currently a big push in the television broadcasting industry. Basically, HD is an attempt to fix many of the perceived issues with television as it has existed over the past 50 years. It is much higher resolution, 1920 pixels wide by 1080 tall as opposed to 720 pixels wide by 486 pixels tall now. It uses square pixels as opposed to rectangular pixels in use on TVs now. Last it's aspect ratio is 16x9 which is much closer to the way we see than the current aspect ratio in use 4x3.
Digital Television: The FCC has mandated that all terrestrial (traditional over the air) broadcasters move to digital broadcasting and give up their current spectrum allocations. Timelines have changed significantly since the late 1990's when this was put forth and the transition is now slated to occur next year (2009). The wireless spectrum that the analog broadcasts are currently using have been auctioned off by the FCC so it seems as though it is definitely going to happen.
Essentially, DTV is very similar to normal television broadcasting but instead of analog signals the signals will be compressed digital (1s and 0s) and will have better quality (digital makes perfect copies) by not degrading over distance and using less of the available spectrum.
MPEG-2 is the codec that it is use with DTV broadcasts both HD and standard definition (SD). Also because less space (less bandwidth) is used broadcasters can offer more channels of programming in SD or a single HD channel plus a low bandwidth data channel if they choose.
Digital TV: A Cringely Crash Course
Internet Protocol Television (IPTV):
IPTV is the delivery of television over IP networks (like the internet). Both the cable companies and traditional telephone companies have high-speed lines into the home that can be used for the delivery of video. Unfortunately, IPTV networks are not typically open (meaning you can receive Jane's video podcast) but in the future they might be. In a lot of ways, IPTV can be seen as an attempt by broadband companies to become cable networks. IPTV generally uses MPEG-4/H.264 streaming for the transmission of video. IPTV is also easily made 2 way as it works over broadband internet connections.
Video On Demand (VoD):
Television delivery networks, specifically cable networks that employ DTV and IPTV networks have been offering video on demand for a couple of years. VoD is very much like streaming on-demand instead of live where a specific file is requested and that is sent to the subscriber and displayed in real-time. VoD requires large video servers and high bandwidth to send television to the subscriber who made the request. It allows for pausing, rewinding and subscription windows (windows of time that you can watch a particular piece of content) as well as integrated payment and billing systems.
VoD was originally used for movie delivery but has recently moved into many content areas including independent content and short form media. One of the more interesting uses is that news services are offering raw footage on VoD (without much context).
Wikipedia: Video on demand
Digital Video Recorders (DVR)/Personal Video Recorders (PVR):
Replay and TiVo ignited a fire with specialized computers that have television tuner capability along with the ability to schedule recordings of shows. They offer the user the ability to record any show they might have access through normal cable or terrestrial broadcast to watch when they choose. They also allow pausing, rewinding, fast forwarding and so on. Particularly compelling is the ability for users to fast forward through commercials which broadcasters have likened to stealing content.
Windows XP Media Center Edition Demo
As you can see, many of these devices are combining functionality, offering access to IPTV, Video On Demand and DVR/PVR capabilities.
Home Media Adapters:
With the prevalence of media storage occurring on home PCs and on the internet a class of devices and software have arisen that I call Home Media Adapters. Essentially these are the means to viewing photographs, audio and video from your computer (or through the internet) on televisions.
Generally a server application will be run on your PC or Mac and it will advertise itself to the network via UPnP (Universal Plug and Play), Rendezvous/Zeroconf/Bonjour, Digital Living Network Alliance (DLNA) or Intel's new Viiv technology. Devices connected to your TV (TiVo, Media Center and others) can then discover these services and offer the ability to browse or view that media.
AirPort Express with iTunes
Various Linksys Routers
Many many more are coming on to or have been on the market..
Current TV - Upload, Watch, Vote, Create Commercials and more..
CBC - Zed - Blogs, P2P and more..
BBC Broadcasting from within Second Life