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Pixels Everywhere! Media Technology and How it is Changing the World

PAT HANRAHAN, Stanford Slides - 2 MB Download - 391 MB Watch the Talk (22:06)

The past two decades have seen the conversion from analog representations of media to digital formats. With the June 12, 2009 cutover to digital broadcast TV, the change is complete. This transformation was due not to new ideas about media, but to changing economics of digital storage, processing, and communication. The ideas and techniques for digital representations of print images, sounds, photographs, and motion video largely preceded the widespread commercial adoption, which was paced by rapidly declining costs.

Print media was the first convert. Laser printers permitted printing high-resolution rendering of arbitrary images - whether text, line drawings, or halftones. The Postscript page-description language and associated products from Adobe, as used in the Apple Laserwriter, led to interactive programs used to compose and design pages, documents, and books.

High-quality digital audio emerged in the mid-seventies, followed by the popular MP3 format, and the now ubiquitous "players" such as the Apple iPod.

Digital photography exploded in the early nineties when CMOS image sensors became available and the cost of storage plummeted. High-quality multi-mega-pixel cameras eclipsed their film counterparts by about 2000. Digital image-processing software such as Photoshop followed. Today people share their photos on web-based services such as flickr.com.

Last to become widespread was video, because of greater storage and bandwidth requirements. Enabled by image-compression techniques such as MPEG, digital video is now the US broadcast standard (ATSC). Digital recorders (TIVO) and players complete the consumer suite.

Huge advances have also occurred in using computers to create media content. Pixar produced the first full-length computer-generated motion picture in 1995 (Toy Story). Today, media production is entirely a digital affair, whether the source is a performance by a human or by a computer.

These developments have occurred due to a close co-evolution of media and technology. Technological advances in storage, networking, computing, and software have made it easier - and, importantly, far less expensive - to store and process digital media representations. To some extent, the demands of the media marketplace have also driven technology. Recording formats such as CD, DVD, and Blu-ray were feasible because of mass consumer media markets, yet devices of all sorts exploited this storage. Today's on-line video services, such as YouTube, are key drivers in network bandwidth deployment. And graphics-processing-units (GPUs), the fast special-purpose chips designed to support realistic, interactive games, also find uses in massive parallel scientific computations.

Developments of the last few decades have not been confined to converting existing media to digital formats. New media have also developed and flourished. Real-time interactive games, with stunning graphic realism, have become a massive market. Media servers hold and deliver your media assets in your home or office, and recently to your cell phone. Video is delivered increasingly via the Internet. People routinely share their music, their pictures, and their videos via Internet services. Virtual worlds, first envisioned over 40 years ago, have blossomed as technology has improved, and have led to new collaboration applications, not limited to games. Electronic books are now becoming popular.

A vital consequence of the digitization of all these media is that they can now be combined, mixed, and integrated in new ways. Software tools for creating, editing, and disseminating mixed media have burgeoned.

What's ahead? Though the conversion-to-digital transition is largely complete, new advances continue to drive digital media. For instance, rather than sensing the "real" image formed by a lens, it is possible to record a form of "digital hologram" that contains information about light traveling on different paths through a focusing lens. This additional information can be used in a "software focus" algorithm to change the focal point of the lens. This has applications in conventional photography, and especially in microscopes. There are many opportunities to sense more than the eye can see and process the signals to obtain photographs and more.

Virtual world simulations of 3D space could grow to encompass "planetary scale," both in imagery and in simulating a virtual environment. But there are huge challenges to address, not just in the technologies to support such environments, but in designs that match evolving understanding of their users.

Today's computers are better at generating output than sensing inputs. While the forty-year-old "mouse" remains a ubiquitous computer input device, smaller mobile devices are spurring innovation. Multi-touch screens, accelerometers, and cameras are becoming common. Microsoft is experimenting with a display screen that can also sense light reflected from one or more fingers touching the screen or a hand waving over it.