(computer science) Audio or video files that can begin playing as they are being downloaded to a computer.
| Sci-Tech Dictionary: streaming media |
(computer science) Audio or video files that can begin playing as they are being downloaded to a computer.
| 5min Related Video: Streaming media |
| Computer Desktop Encyclopedia: streaming audio |
A one-way audio transmission over a data network. It is widely used on the Web as well as company networks to play audio clips and Internet radio. Computers in home networks stream audio (mostly music) to digital media hubs connected to home theaters. Unlike sound files that are played after the entire file has been downloaded and stored, streaming audio begins playing after only a small amount is received, and the audio data are not stored permanently in the destination computer. See digital media hub.
If the streaming audio is broadcast live, then it may be called "real-time audio." However, technically, real time means no delays, and there is a built-in delay in streaming audio (see real-time audio).
It's Already in the Buffer
Listening to momentary blips in music or a conversation is annoying, and the only way to compensate for that over an erratic network such as the Internet is to get some of the audio data into the computer before you start listening to it. In streaming audio, both the client and server cooperate for uninterrupted sound. The client side stores a few seconds of sound in a buffer before it starts sending it to the speakers. Throughout the session, it continues to receive audio data ahead of time.
VoIP Is More Demanding
Voice over IP (VoIP) is more taxing on the network than streaming audio. It requires real-time, two-way transmission with sufficient bandwidth for audio coming in and going out at the same time without being able to buffer any of it. See streaming video, VoIP and Windows Media.
Download Computer Desktop Encyclopedia to your iPhone/iTouch
| Wikipedia: Streaming media |
| This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (October 2007) |
Streaming media are multimedia that are constantly received by, and normally presented to, an end-user while being delivered by a streaming provider (the term "presented" is used in this article in a general sense that includes audio or video playback). The name refers to the delivery method of the medium rather than to the medium itself. The distinction is usually applied to media that are distributed over telecommunications networks, as most other delivery systems are either inherently streaming (e.g., radio, television) or inherently non-streaming (e.g., books, video cassettes, audio CDs). The verb 'to stream' is also derived from this term, meaning to deliver media in this manner.
Contents |
Attempts to display media on computers date back to the earliest days of computing in the mid-20th century. However, little progress was made for several decades, primarily due to the high cost and limited capabilities of computer hardware.
From the late 1980s through the 1990s, consumer-grade personal computers became powerful enough to display various media. The primary technical issues related to streaming were:
However, computer networks were still limited, and media was usually delivered over non-streaming channels, such as by downloading a digital file from a remote web server and then saving it to a local drive on the end user's computer or storing it as a digital file and playing it back from CD-ROMs.
During the late 1990s and early 2000s, Internet users saw:
These advances in computer networking combined with powerful home computers and modern operating systems made streaming media practical and affordable for ordinary consumers. Stand-alone Internet radio devices offer listeners a "no-computer" option for listening to audio streams.
In general, multimedia content has a large volume, so media storage and transmission costs are still significant; to offset this somewhat, media are generally compressed for both storage and streaming.
Increasing consumer demand for streaming of high definition (HD) content to different devices in the home has led the industry to develop a number of technologies, such as Wireless HD or ITU-T G.hn, which are optimized for streaming HD content without forcing the user to install new networking cables.
A media stream can be on demand or live. On demand streams are stored on a server for a long period of time, and are available for transmission at a user's request. Live streams are only available at one particular time, as in a video stream of a live sporting event.
Research in streaming and media is ongoing and representative research can be found in the Journal of Multimedia.
Streaming media storage size (in the common file system measurements megabytes, gigabytes, terabytes, and so on) is calculated from the streaming bandwidth and length of the media using the following formula (for a single user and file):
since 1 megabyte = 8 * 1024*1024 bits.
Real world example:
One hour of video encoded at 300 kbit/s (this is a typical broadband video in 2005 and it is usually encoded in a 320×240 pixels window size) will be:
If the file is stored on a server for on-demand streaming and this stream is viewed by 1,000 people at the same time using a Unicast protocol, the requirement is:
This is equivalent to around 135 GiB per hour. Of course, using a multicast protocol the server sends out only a single stream that is common to all users. Hence, such a stream would only use 300 kbit/s of serving bandwidth. See below for more information on these protocols.
Designing a network protocol to support streaming media raises many issues, such as:
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
| streaming server (technology) | |
| user datagram protocol (communications) | |
| NetShow (technology) |
| What is streaming media? | |
| How much does streaming media cost? | |
| How does streaming media can help in the country? |
Copyrights:
![]() | Sci-Tech Dictionary. McGraw-Hill Dictionary of Scientific and Technical Terms. Copyright © 2003, 1994, 1989, 1984, 1978, 1976, 1974 by McGraw-Hill Companies, Inc. All rights reserved. Read more | |
![]() | Computer Desktop Encyclopedia. THIS COPYRIGHTED DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction is strictly prohibited without permission from the publisher. © 1981-2009 Computer Language Company Inc. All rights reserved. Read more | |
![]() | Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Streaming media". Read more |
Mentioned in