Mediaprocessor

A Mediaprocessor is a microprocessor-based System-on-a-chip which is designedto deal with digital streaming data at real-time (e.g. display refresh) rates. These devices can also be considered a class of digital signal processors.

Unlike similar Graphics processing units, which are used for computer displays, mediaprocessors are targeted at digital televisions and set-top boxes.

The streaming digital media classes include:
* uncompressed digital video
* compressed digital video - e.g. MPEG-1, MPEG-2, MPEG-4
* digital audio- e.g. PCM, AAC

Such SOCs are composed of:
* a microprocessor optimized to deal with these media datatypes
* a memory interface
* streaming media interfaces
* specialized functional units to help deal with the various digital media codecs

The microprocessor might have these optimizations:
* vector processing or SIMD functional units to efficiently deal with these media datatypes
* DSP-like features

Previous to mediaprocessors, these streaming media datatypes were processed using fixed-function, hardwired ASICs, which could not be updated in the field. This was a big disadvantage when anyof the media standards were changed. Since mediaprocessors are software programmed devices, theprocessing done on them could be updated with new software releases. This allowed new generations ofsystems to be created without hardware redesign. For set-top boxes this even allows for the possibility of in-the-field upgrade by downloading of new software through cable or satellite networks.

Companies that pioneered the idea of mediaprocessors (and created the marketing term of mediaprocessor) included:
* MicroUnity "Mediaprocessor" - device never reached production
* Equator Semiconductor "BSP" line - their processors are used in Hitachi televisions, company acquired by Pixelworks
* Chromatic Research "MPact" line - their products were used on some PC graphics cards in the mid 1990s, company acquired by ATI Technologies
* Philips "TriMedia" line - used in Philips, Dell, Sony, etc. consumer electronics, Philips Semiconductors split of from Philips and became NXP Semiconductors in 2006

Consumer electronics companies have successfully dominated this market by designing their own mediaprocessors and integrating them into their video products. Companies such as Philips, Samsung, Matsushita, Fujitsu, Mitsubishi have their own in-house mediaprocessor devices.

Newer generations of such devices now use various forms of multiprocessing—multiple CPUs, DSPs, ALUs in order to deal with the vastly increased computational needs when dealing with high definition television signals.

External links

* [http://www.microunity.com http://www.microunity.com]
* [http://www.equator.com http://www.equator.com]
* [http://www.philips.com http://www.philips.com]
* [http://www.nxp.com http://www.nxp.com]