Electrical engineering is a professional engineering discipline that generally deals with the study and application of electricity, electronics, and electromagnetism. This field first became an identifiable occupation in the later half of the 19th century after commercialization of the electric telegraph, the telephone, and electric power distribution and use. Subsequently, broadcasting and recording media made electronics part of daily life. The invention of the transistor, and later the integrated circuit, brought down the cost of electronics to the point they can be used in almost any household object.
Electrical engineering has now subdivided into a wide range of subfields including electronics, digital computers, computer engineering, power engineering, telecommunications, control systems, robotics, radio-frequency engineering, signal processing, instrumentation, and microelectronics. Many of these subdisciplines overlap with other engineering branches, spanning a huge number of specializations such as hardware engineering, power electronics, electromagnetics & waves, microwave engineering, nanotechnology, electrochemistry, renewable energies, mechatronics, electrical materials science, and much more. See glossary of electrical and electronics engineering.
Electrical engineers typically hold a degree in electrical engineering or electronic engineering. Practicing engineers may have professional certification and be members of a professional body. Such bodies include the Institute of Electrical and Electronics Engineers (IEEE) and the Institution of Engineering and Technology (IET) (formerly the IEE).
Electrical engineers work in a very wide range of industries and the skills required are likewise variable. These range from basic circuit theory to the management skills required of a project manager. The tools and equipment that an individual engineer may need are similarly variable, ranging from a simple voltmeter to a top end analyzer to sophisticated design and manufacturing software.
Audio Video Coding Standard (AVS) refers to the digital audio and digital video series compression standard formulated by Audio and Video coding standard workgroup of China according to the open international rules. At present, the formulation of two-generation AVS standards has been completed.[1]
The first generation AVS standard includes “Information Technology, Advanced Audio Video Coding, Part 2: Video” (AVS1 for short) and “Information Technology, Advanced Audio Video Coding Part 16: Radio Television Video” (AVS+ for short).
For the second generation AVS standard, referred to as AVS2, the primary application target is Ultra HD (High Definition) video, supporting the efficient compression of ultra high-resolution (4K above), HDR (High Dynamic Range) videos, and it has been submitted to the IEEE international standard (Standard No.: IEEE1857.4) for application.
The “AVS Patent Pool” provides one-stop authorization for AVS standard, which charges only a small amount of royalties for terminal products, excluding content providers and operators. The royalty for the first generation AVS standard is one yuan per terminal.[2]
In order to propel the development and promotion of the AVS standard, Huawei, TCL, Skyworth and other companies established Zhongguancun audiovisual industry technology innovation alliance (abbreviation: AVS industry alliance), which is devoted to the development and promotion of the AVS standard.
Audiovisual (AV) means possessing both a sound and a visual component, such as slide-tape presentations,[1] films, television programs, church services and live theater productions.
Audiovisual service providers frequently offer web streaming, video conferencing and live broadcast services.[2]
Computer-based audiovisual equipment is often used in education, with many schools and universities installing projection equipment and using interactive whiteboard technology.
Another audiovisual expression is the visual presentation of sound (visual music).
Streaming media is multimedia that is constantly received by and presented to an end-user while being delivered by a provider. The verb "to stream" refers to the process of delivering or obtaining media in this manner; the term refers to the delivery method of the medium, rather than the medium itself, and is an alternative to file downloading, a process in which the end-user obtains the entire file for the content before watching or listening to it.
A client end-user can use their media player to start playing the data file (such as a digital file of a movie or song) before the entire file has been transmitted. Distinguishing delivery method from the media distributed applies specifically to telecommunications networks, as most of the delivery systems are either inherently streaming (e.g. radio, television, streaming apps) or inherently non-streaming (e.g. books, video cassettes, audio CDs). For example, in the 1930s, elevator music was among the earliest popularly available streaming media; nowadays Internet television is a common form of streamed media. The term "streaming media" can apply to media other than video and audio such as live closed captioning, ticker tape, and real-time text, which are all considered "streaming text".
The term "streaming" was first used for tape drives made by Data Electronics Inc. for drives meant to slowly ramp up and run for the entire track; the slow ramp times resulted in lower drive costs, making a more competitive product. "Streaming" was applied in the early 1990s as a better description for video on demand on IP networks; at the time such video was usually referred to as "store and forward video",[1] which was misleading nomenclature.
Live streaming is the delivery of Internet content in real-time, as events happen, much as live television broadcasts its contents over the airwaves via a television signal. Live internet streaming requires a form of source media (e.g. a video camera, an audio interface, screen capture software), an encoder to digitize the content, a media publisher, and a content delivery network to distribute and deliver the content. Live streaming does not need to be recorded at the origination point, although it frequently is.
As of 2017, "streaming" generally refers to the situation where a user watches digital video content or listens to digital audio content on a computer screen and speakers (ranging from a smartphone, through a desktop computer to a large-screen home entertainment system) over the Internet. With streaming content, the user does not have to download the entire digital video or digital audio file before they start to play it.
There are challenges with streaming content on the Internet. If the user does not have enough bandwidth in their Internet connection, they may experience stops in the content and some users may not be able to stream certain content due to not having compatible computer or software systems.
Some popular streaming services are the video sharing website YouTube; Twitch and Mixer, which live stream the playing of video games; Netflix, which streams movies and TV shows; and Spotify and Apple Music, which stream music.
Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. This is in contrast to analog video, which represents moving visual images with analog signals. Digital video comprises a series of digital images displayed in rapid succession.
Digital video was first introduced commercially in 1986 with the Sony D1 format, which recorded an uncompressed standard definition component video signal in digital form. In addition to uncompressed formats, popular compressed digital video formats today include H.264 and MPEG-4. Interconnect standards for digital video include HDMI, DisplayPort, Digital Visual Interface (DVI) and serial digital interface (SDI).
Digital video can be copied with no degradation in quality. In contrast, when analog sources are copied, they experience generation loss. Digital video can be stored on digital media such as Blu-ray Disc, on computer data storage or streamed over the Internet to end users who watch content on a desktop computer screen or a digital smart TV. In everyday practice, digital video content such as TV shows and movies also includes a digital audio soundtrack.
0 comments:
Post a Comment