Streaming bandwidth and storage

Streaming media storage size (in the common file system measurements megabytes, gigabytes, terabytes, and so on) is calculated from streaming bandwidth and length of the media with the following formula (for a single user and file):

storage size (in megabytes) = length (in seconds) * bit rate (in kbit/s) / (8 * 1024)
(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 for 2005 and it's usually encoded in a 320×240 pixels window size) will be:


(3,600 s * 300,000 bit/s) / (8*1024*1024) give around 128 MB of storage
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, you would need:

300 kbit/s * 1,000 = 300,000 kbit/s = 300 Mbit/s of bandwidth
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.

All About Streaming

Streaming media is multimedia that is constantly received by, and normally presented to, an end-user while it is 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.

History

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 with streaming were:

having enough CPU power and bus bandwidth to support the required data rates
creating low-latency interrupt paths in the OS to prevent buffer underrun[citation needed]
However, computer networks were still limited, and media was usually delivered over non-streaming channels, such as download of a digital file from a remote web server that was then saved to a local drive on the end user's computer or as a digital file stored and played back from CD-ROMs.

During the late 1990s and early 2000s, internet users saw:

greater network bandwidth, especially in the last mile
increased access to networks, especially the Internet
use of standard protocols and formats, such as TCP/IP, HTTP, and HTML
commercialization of the Internet
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 are offering listeners a "no-computer" option for listening to audio streams. But it needs further adhoc references to it.

In general, multimedia content is large, so media storage and transmission costs are still significant; to offset this somewhat, media is 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 WirelessHD or ITU-T G.hn, which are optimized for streaming of 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 to be transmitted at a user's request. Live streams are only available at one particular time, as in a video stream of a live sporting event.