EVOLVING TECHNOLOGIES FOR MULTIMEDIA SYSTEMS
Multimedia applications use a number of technologies generated for both commercial business application as well as the video game industry.
Let us review some of these technologies in this section.
Hypermedia documents are documents which have text, embedded or linked multimedia objects such as image, audio, hologram, or full-motion video.
Hypertext systems allow authors to link information together, create information paths through a large volume of related text in documents.
It also allows to annotate existing text, and append notes.
It allows fast and easy searching and reading of selected excerpts.
It is an extension of hypertext.
In that, we can include texts, any kind of information that can be stored in electronic storage, such as audio, animated video, graphics or full-motion video.
Hypermedia documents used for electronic mail and work flow applications provide a rich functionality for exchanging a variety of information types. The hypermedia document is a definition of a document and a set of pointers to help locate the various elements of the document on the network.
Multimedia stimulated the development of general-purpose speech interfaces. Speech synthesis and speech recognition are fundamental requirement for hyperspeech systems. Speech recognition is nothing but converting the analog speech into a computer action and into ASCII text. Speech-recognition systems cannot segment a stream of sounds without breaks into meaningful units. The user must speak in a stilted fashion. He should make sure to interpose silence between each word.
HDTV AND UDTV
HDTV is an acronym of High-Definition Television.
The broadcasting standards such as NTSC, PAL, SECAM, NHK have an idea of bringing the world together on a single high-definition Television broadcasting standard.
The japanese broadcasting services developed a 1125-line, along MUSE system. A competing standard in the U.S. changed direction from analog to digital technology:A 1125-line digital HDTV has been developed and is being commercialized. NHK of Japan is trying to leapfrog the digital technology to develop ultra definition television (digital UDTV) featuring approximately 3000 lines
3D TECHNOLOGIES AND HOLOGRAPHY
Three-dimensional technologies are concerned with two areas: pointing devices and displays. 3-D pointing devices are essential to manipulate object in a 3-D display system. 3-D displays are achieved using holography techniques.
The techniques developed for holography have been adapted for direct computer use.
Fuzzy logic is logic which is used for low-level process controllers.
Use of fuzzy logic in multimedia chips is the key to the emerging graphical interfaces of the future. It is expected to become an integral part of multimedia hardware. Fuzzy logic has mathematical principles. Hence, the application of multimedia can benefit those principles.
Digital Signal Processing
Digital Signal Processing are used in applications such as digital servos in hard disk drives, and fax/modems. DSP technology is used in Digital wireless communications, such as personal communication networks (pens), wireless local area networks and digital cordless phones.
DSP Architectures and Applications
A typical DSP operating system architecture would contain the following subsystems:
Memory Management: DSP architectures provide dynamic allocation of arrays from multiple segments, including RAM, SRAM and DRAM.
Hardware-Interrupt handling: A DSP operating system must be designed to minimize hardware-interrupt latency to ensure fast response to real time events for applications, such as servo systems. Multitasking: DSPs need real-time kernels that provide pre-emptive multitasking and user-defined and dynamic task prioritization
INTERTASK SYNCHRONIZATION AND COMMUNICATION
Mechanisms for intertask communication include message queues, semaphores, shared memory, and quick response event flags. Multiple timer services: The ability for the developer to set system clock interrupt managed timers to control and synchronize tasks is needed for most real-time applications.
Device-Independent I/O: DSP operating system should supports
(i) Asynchronous data stream
(ii) Synchronous message passing.
Use of DSP' s has evolved from traditional general purpose digital signal processors to application-specific and customizable DSPs. DSPs were conceived as math engines with a system architecture that was like that of a mini-computer with an array processor.