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[[File:Sample Webcast Screenshot.png|thumb|A typical [[webcast]], streaming in an embedded media player]]
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[[File:Schou FishCam.jpeg|thumb|lt=A still from a live feed of a fish tank with multiple stream encoding qualities|A still from a [[live stream]] of a fish tank,<ref>{{cite web|url=http://fish.schou.me/|archiveurl=https://archive.today/20141216154536/http://fish.schou.me/|deadurl=yes|title=Schou FishCam|date=16 December 2014|archivedate=16 December 2014|publisher=}}</ref> Schou FishCam]]
'''Streaming media''' is [[multimedia]] that is constantly received by and presented to an [[End-user (computer science)|end-user]] while being delivered by a provider. The verb "to stream" refers to the process of delivering or obtaining media in this manner;{{Clarification needed|date=May 2018}} 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 (software)|media player]] to start playing the [[digital video]] content or listens to [[digital audio]] content before the entire file has been transmitted. Distinguishing delivery method from the media distributed applies specifically to [[telecommunications network]]s, as most of the delivery systems are either inherently streaming (e.g. [[radio]], [[television]], streaming apps) or inherently non-streaming (e.g. [[books]], [[Videotape|video cassettes]], audio [[Compact Disc|CD]]s). 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".
[[Live media|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.
There are challenges with streaming content on the Internet. If the user does not have enough [[Bandwidth (signal processing)|bandwidth]] in their Internet connection, they may experience stops, lags or slow buffering 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 include the [[video sharing website]] [[YouTube]], [[Twitch.tv|Twitch]] and [[Mixer (website)|Mixer]], which live stream the playing of video games; [[Netflix]] and [[Amazon Video]], which stream [[Film|movie]]s and [[Television show|TV show]]s; and [[Spotify]], [[Apple Music]] and [[Tidal (service)|TIDAL]], which stream [[music]].
==History==
In the early 1920s, [[George O. Squier]] was granted [[patent]]s for a system for the transmission and distribution of signals over electrical lines<ref>{{cite web| url = http://www.google.com/patents?id=5pV5AAAAEBAJ&dq=1641608| title = US Patent 1,641,608 | publisher = [[Google Patents]]}}</ref> which was the technical basis for what later became ''[[Muzak Holdings|Muzak]]'', a technology streaming continuous music to commercial customers without the use of [[radio]]. 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: having enough [[CPU]] power and [[bus (computing)|bus]] [[Bandwidth (computing)|bandwidth]] to support the required data rates and creating [[Latency (engineering)|low-latency]] interrupt paths in the [[operating system]] to prevent [[buffer underrun]] and thus enable skip-free streaming of the content. However, computer networks were still limited in the mid-1990s, and audio and video media were usually delivered over non-streaming channels, such as by [[download]]ing a digital file from a remote 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-ROM]]s.
===Late 1990s – early 2000s===
During the late 1990s and early 2000s, users had increased access to computer networks, especially the [[Internet]], and especially during the early 2000s, users had access to increased network [[Bandwidth (signal processing)|bandwidth]], especially in the "[[last mile]]". These technological improvements facilitated the streaming of audio and video content to computer users in their homes and workplaces. As well, there was an increasing use of standard protocols and formats, such as [[Internet protocol suite|TCP/IP]], [[HyperText Transfer Protocol|HTTP]], [[HyperText Markup Language|HTML]] and the Internet became increasingly commercialized, which led to an infusion of investment into the sector. The band [[Severe Tire Damage (band)|Severe Tire Damage]] was the first group to perform live on the Internet. On June 24, 1993, the band was playing a gig at [[PARC (company)|Xerox PARC]] while elsewhere in the building, scientists were discussing new technology (the [[Mbone]]) for broadcasting on the Internet using [[multicasting]]. As proof of PARC's technology, the band's performance was broadcast and could be seen live in Australia and elsewhere. In a March 2017 interview, band member Russ Haines stated that the band had used approximately "half of the total bandwidth of the internet" to stream the performance, which was a 152-by-76 pixel video, updated eight to twelve times per second, with audio quality that was "at best, a bad telephone connection".<ref>[https://www.youtube.com/watch?v=HRa2pE5-Ny0 "History of the Internet Pt. 1 - The First Live Stream"]. ''From YouTube.com.'' Internet Archive - Stream Division. 5 April 2017. Retrieved 2018-01-13.</ref>
[[Microsoft]] Research developed a Microsoft TV application which was compiled under MS Windows Studio Suite and tested in conjunction with Connectix QuickCam. [[RealNetworks]] was also a pioneer in the streaming media markets, when it broadcast a [[baseball]] game between the [[New York Yankees]] and the [[Seattle Mariners]] over the Internet in 1995.<ref>{{cite web |url=http://www.fundinguniverse.com/company-histories/RealNetworks-Inc-Company-History.html |publisher=Funding Universe |title=RealNetworks Inc. |accessdate=2011-07-23}}</ref> The first symphonic concert on the Internet took place at the [[Paramount Theatre (Seattle, Washington)|Paramount Theater]] in [[Seattle]], Washington on November 10, 1995.<ref>{{cite magazine |author=<!--Staff writer(s); no by-line.--> |title= Cyberian Rhapsody |magazine=Billboard |location= United States|publisher= Lynne Segall|date=17 Feb 1996}}</ref> The concert was a collaboration between The Seattle Symphony and various guest musicians such as [[Slash (musician)|Slash]] (Guns 'n Roses, Velvet Revolver), [[Matt Cameron]] (Soundgarden, Pearl Jam), and [[Barrett Martin]] (Screaming Trees). When ''[[Word Magazine]]'' launched in 1995, they featured the first-ever streaming soundtracks on the Internet. {{Citation needed|date=March 2017}}
[[Metropolitan Opera Live in HD]] is a program in which the [[Metropolitan Opera]] streams an [[opera]] performance "live", as the performance is taking place. In 2013–2014, 10 operas were transmitted via satellite into at least 2,000 theaters in 66 countries.<ref>Pamela McClintock, [http://www.hollywoodreporter.com/news/met-opera-standoff-threatens-60-723614 "Met Opera Standoff Threatens $60 Million Theater Business", ''The Hollywood Reporter''] (online), August 7, 2014 on hollywoodreporter.com</ref>
===Etymology===
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]] and later live video on IP networks first by [[Starlight Networks]] for video streaming and [[Real Networks]] for audio streaming; at the time such video was usually referred to as "store and forward video",<ref>{{cite web| url = http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=188525&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel2%2F536%2F4777%2F00188525.pdf%3Farnumber%3D188525| title = On buffer requirements for store-and-forward video on demand service circuits | accessdate =| publisher = [[IEEE]]}}</ref> which was misleading nomenclature.
===Business developments===
The first commercial streaming product appeared in late 1992 and was named StarWorks<ref name="StarWorks">{{cite web |url=https://www.researchgate.net/publication/3556409_StarWorks-a_video_applications_server |title=CompCon Spring 1993-StarWorks-a video applications server}}</ref> and enabled on demand MPEG-1 full motion videos to be randomly accessed on corporate [[Ethernet]] networks. Starworks was from [[Starlight Networks]], who also pioneered live video streaming on Ethernet and via [[Internet Protocol]] over satellites with [[Hughes Network Systems]].<ref name="Starlight Networks and Hughes Network Systems">{{cite web |url=http://www.thefreelibrary.com/Starlight+Networks+and+Hughes+Network+Systems+Plan+Corporate...-a017588314 |title=Starlight Networks and Hughes Network Systems}}</ref> Other early companies who created streaming media technology include [[RealNetworks]] (then known as Progressive Networks) and Protocomm both prior to wide spread World Wide Web usage and once the web became popular in the late 90s, streaming video on the internet blossomed from startups such as VDOnet, acquired by [[RealNetworks]], and Precept, acquired by [[Cisco]].
[[Microsoft]] developed a media player known as [[ActiveMovie]] in 1995 that allowed streaming media and included a proprietary streaming format, which was the precursor to the streaming feature later in [[Windows Media Player]] 6.4 in 1999. In June 1999 [[Apple Inc.|Apple]] also introduced a streaming media format in its [[QuickTime]] 4 application. It was later also widely adopted on websites along with RealPlayer and Windows Media streaming formats. The competing formats on websites required each user to download the respective applications for streaming and resulted in many users having to have all three applications on their computer for general compatibility.
In 2000 Industryview.com launched its "world's largest streaming video archive" website to help businesses promote themselves.<ref>{{cite magazine |last=Hebert |first=Steve |date=November 2000 |title=Streaming Video Opens New Doors |magazine=Videography|page=164}}</ref> Webcasting became an emerging tool for business marketing and advertising that combined the immersive nature of television with the interactivity of the Web. The ability to collect data and feedback from potential customers caused this technology to gain momentum quickly.<ref>{{cite magazine |last=Reinstein |first=Bill |date=25 June 2001 |title=Webcasts Mature as Marketing Tool |magazine=DM News|page=24}}</ref>
Around 2002, the interest in a single, unified, streaming format and the widespread adoption of [[Adobe Flash]] prompted the development of a video streaming format through Flash, which was the format used in Flash-based players on many popular video hosting sites, such as [[YouTube]], now defaulting to [[HTML5 video]].<ref>{{Cite news|url=https://youtube-eng.googleblog.com/2015/01/youtube-now-defaults-to-html5_27.html|title=YouTube now defaults to HTML5 <nowiki><video></nowiki>|last=|first=|date=|work=YouTube Engineering and Developers Blog|access-date=2018-02-20|archive-url=|archive-date=|dead-url=|language=en-US}}</ref> Increasing consumer demand for live streaming has prompted YouTube to implement a new live streaming service to users.<ref>{{cite web |url=http://news.cnet.com/8301-17939_109-9883062-2.html |author=Josh Lowensohn |year=2008 |title=YouTube to Offer Live Streaming This Year |accessdate=2011-07-23}}</ref> Presently the company also offers a (secured) link returning the available connection speed of the user.<ref>{{cite web|url=https://www.youtube.com/my_speed# | title=YouTube Video Speed History |accessdate=April 30, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120426225550/http://www.youtube.com/my_speed |archivedate=April 26, 2012 }}</ref>
The [[Recording Industry Association of America]] (RIAA) revealed through its 2015 earnings report that streaming services were responsible for 34.3 percent of the year's total [[music industry]]'s revenue, growing 29 percent from the previous year and becoming the largest source of income, pulling in around $2.4 billion.<ref>{{cite web|title=News and Notes on 2015 RIAA Shipment and Revenue Statistics|url=https://www.riaa.com/wp-content/uploads/2016/03/RIAA-2015-Year-End-shipments-memo.pdf|publisher=RIAA|accessdate=5 January 2017}}</ref><ref>{{cite web|title=Streaming made more revenue for music industry in 2015 than digital downloads, physical sales|url=http://www.washingtontimes.com/news/2016/mar/23/streaming-made-more-revenue-for-music-industry-in-/|publisher=The Washington Times|accessdate=5 January 2017}}</ref> US streaming revenue grew 57 percent to $1.6 billion in the first half of 2016 and accounted for almost half of industry sales.<ref>{{cite web|last1=Shaw|first1=Lucas|title=The Music Industry Is Finally Making Money on Streaming|url=https://www.bloomberg.com/news/articles/2016-09-20/spotify-apple-drive-u-s-music-industry-s-8-first-half-growth|publisher=Bloomberg|accessdate=5 January 2017|date=20 September 2016}}</ref>
==Use by consumers==
[[File:羽村市動物公園 ニコ生 2017 (32782507624).jpg|left|thumb|Live streaming service at zoo by [[Niconico]]]]
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 device]]s emerged to offer listeners a no-computer option for listening to audio streams. These audio streaming services have become increasingly popular over recent years, as streaming music hit a record of 118.1 billion streams in 2013.<ref>"[https://www.ccianet.org/wp-content/uploads/2014/10/Sky-Is-Rising-2014.pdf The Sky is Rising]", Masnick, M., Ho, M., Hung, J., Beadon, L.. Accessed 8 February 2015.</ref> In general, multimedia content has a large volume, so media storage and transmission costs are still significant. To offset this somewhat, media are generally [[data compression|compressed]] for both storage and streaming. Increasing consumer demand for streaming of [[High definition television|high definition]] (HD) content has led the industry to develop a number of technologies such as [[WirelessHD ]] or [[ITU-T]] [[G.hn]], which are optimized for streaming HD content without forcing the user to install new [[networking cables]]. In 1996, digital pioneer [[Marc Scarpa]] produced the first large-scale, online, live broadcast in history, the [[Adam Yauch]]-led [[Tibetan Freedom Concert]], an event that would define the format of social change broadcasts. Scarpa continued to pioneer in the streaming media world with projects such as [[Woodstock '99]], Townhall with President Clinton, and more recently Covered CA's campaign "Tell a Friend Get Covered" which was live streamed on YouTube.
{{quote box|quote="Streaming creates the illusion—greatly magnified by headphone use, which is another matter—that music is a utility you can turn on and off; the water metaphor is intrinsic to how it works. It dematerializes music, denies it a crucial measure of autonomy, reality, and power. It makes music seem disposable, impermanent. Hence it intensifies the ebb and flow of pop fashion, the way [[List of viral music videos|musical 'memes']] rise up for a week or a month and are then forgotten. And it renders our experience of individual artists/groups shallower."|source=—[[Robert Christgau]], 2018<ref>{{cite web|last=Christgau|first=Robert|authorlink=Robert Christgau|url=http://robertchristgau.com/xgausez.php|title=Xgau Sez|date=November 20, 2018|website=robertchristgau.com|accessdate=November 21, 2018}}</ref>||width=20%|align=right|style=padding:8px;}}
As of 2016, a media stream can be streamed either "live" or "on demand". Live streams are generally provided by a means called "true streaming". True streaming sends the information straight to the computer or device without saving the file to a hard disk. On-demand streaming is provided by a means called ''progressive streaming'' or ''[[progressive download]]''. Progressive streaming saves the file to a hard disk and then is played from that location. On-demand streams are often saved to hard disks and servers for extended amounts of time; while the live streams are only available at one time only (e.g., during the football game).<ref>Grant and Meadows. (2009). Communication Technology Update and Fundamentals 11th Edition. pp.114</ref> Streaming media is increasingly being coupled with use of [[social media]]. For example, sites such as [[YouTube]] encourage social interaction in webcasts through features such as [[live chat]], [[online survey]]s, user posting of comments online and more. Furthermore, streaming media is increasingly being used for [[social business]] and [[e-learning]].<ref>{{cite web|url=http://web.inxpo.com/casting-calls/bid/113793/The-Future-of-Webcasting|title=The Future of Webcasting|last=Kellner|first=Scott|date=28 February 2013|publisher=INXPO|accessdate=15 May 2013|deadurl=yes|archiveurl=https://web.archive.org/web/20130703142337/http://web.inxpo.com/casting-calls/bid/113793/The-Future-of-Webcasting|archivedate=3 July 2013|df=}}</ref> Due the popularity of the streaming medias, many developers have introduced free HD movie streaming apps for the people who use smaller devices such as tablets and smartphones for everyday purposes.
The [[Horowitz Research]] State of Pay TV, OTT and SVOD 2017 report said that 70 percent of those viewing content did so through a streaming service, and that 40 percent of TV viewing was done this way, twice the number from five years earlier. [[Millennials]], the report said, streamed 60 percent of content.<ref>{{cite journal|title=Horowitz: Streaming Is the New Normal|last=Umstead|first=R. Thomas|work=[[Broadcasting & Cable]]|date=5 June 2017|page=4}}</ref>
===Transition from a DVD based to streaming based viewing culture===
One of the movie streaming industry’s largest impacts was on the [[DVD]] industry, which effectively met its demise with the mass popularization of online content. The rise of media streaming caused the downfall of many DVD rental companies such as [[Blockbuster LLC|Blockbuster]]. In July 2015 the [[New York Times]] published an article about [[Netflix]]'s DVD services. It stated that Netflix was continuing their DVD services with 5.3 million subscribers, which was a significant drop from the previous year. On the other hand, their streaming services had 65 million members.<ref>Steel, Emily. Netflix refines it's DVD business, even as streaming unit booms. July 26, 2015. newyorktimes.com. September 29, 2017</ref> In a March 2016 study assessing the “Impact of Movie Streaming over traditional DVD Movie Rental” it was found that respondents did not purchase DVD movies nearly as much anymore, if at all, as streaming had taken over the market. According to the study, viewers did not find movie quality to be significantly different between DVD and online streaming. Issues that respondents believed needed improvement with movie streaming included functions of fast forwarding or rewinding, as well as search functions.<ref name="autogenerated1">{{cite web|url=http://www.jiii.org/uploadfile/2016/0215/20160215101852372.pdf|title=JIII.org|publisher=}}</ref> The article highlighted that the quality of movie streaming as an industry would only increase in time, as advertising revenue continued to soar on a yearly basis throughout the industry, providing incentive for quality content production.<ref name="autogenerated1"/>
==Bandwidth and storage==
[[File:Unicast streaming.svg|thumb|Unicast connections require multiple connections from the same streaming server even when it streams the same content]]
A broadband speed of 2 Mbit/s or more is recommended for streaming [[standard definition]] video without experiencing buffering or skips, especially live video,<ref>{{cite web | url=https://www.broadbandchoices.co.uk/guides/internet/watching-tv-online | title=How to watch live TV online: The complete guide | work=broadbandchoices | date=20 May 2016 | accessdate=1 October 2016 | author=Staples, Kim}}</ref> for example to a [[Roku]], [[Apple TV]], [[Google TV]] or a Sony TV Blu-ray Disc Player. 5 Mbit/s is recommended for High Definition content and 9 Mbit/s for Ultra-High Definition content.<ref>Minimum requirements for Sony TV Blu-ray Disc Player, on advertisement attached to a NetFlix DVD{{Nonspecific|date=March 2011}}</ref> Streaming media storage size is calculated from the streaming bandwidth and length of the media using the following formula (for a single user and file) requires a storage size in [[megabyte]]s which is equal to length (in seconds) × [[bit rate]] (in bit/s) / (8 × 1024 × 1024). For example, one hour of digital video encoded at 300 kbit/s (this was a typical broadband video in 2005 and it was usually encoded in a 320 × 240 pixels window size) will be:
(3,600 s × 300,000 bit/s) / (8×1024×1024) requires around 128 [[Megabyte|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, the requirement is 300 kbit/s × 1,000 = 300,000 kbit/s = 300 Mbit/s of bandwidth. This is equivalent to around 135 [[gigabyte|GB]] per hour. Using a [[multicast]] protocol the server sends out only a single stream that is common to all users. Therefore, such a stream would only use 300 kbit/s of serving bandwidth. See below for more information on these protocols. The calculation for live streaming is similar. Assuming that the seed at the encoder is 500 kbit/s and if the show lasts for 3 hours with 3,000 viewers, then the calculation is number of [[Megabyte|MB]]s transferred = encoder speed (in bit/s) × number of seconds × number of viewers / (8*1024*1024). The results of this calculation are as follows: number of [[Megabyte|MB]]s transferred = 500 x 1024 (bit/s) × 3 × 3,600 ( = 3 hours) × 3,000 (number of viewers) / (8*1024*1024) = 1,977,539 [[Megabyte|MB]]
== Protocols ==
The audio stream is compressed to make the file size smaller using an [[audio coding format]] such as [[MP3]], [[Vorbis]], [[Advanced Audio Coding|AAC]] or [[Opus (audio format)|Opus]]. The video stream is compressed using a [[video coding format]] to make the file size smaller. Video coding formats include [[H.264]], [[High Efficiency Video Coding|HEVC,]] [[VP8]] or [[VP9]]. Encoded audio and video streams are assembled in a container "[[bitstream]]" such as [[MPEG-4|MP4]], [[Flash Video|FLV]], [[WebM]], [[Advanced Systems Format|ASF]] or [[Internet Streaming Media Alliance|ISMA]]. The bitstream is delivered from a streaming server to a streaming client (e.g., the computer user with their [[Internet]]-connected [[laptop]]) using a transport protocol, such as Adobe's [[Real Time Messaging Protocol|RTMP]] or [[Real-time Transport Protocol|RTP]]. In the 2010s, technologies such as Apple's [[HTTP Live Streaming|HLS]], Microsoft's Smooth Streaming, Adobe's HDS and non-proprietary formats such as [[MPEG-DASH]] have emerged to enable [[adaptive bitrate streaming]] over [[HTTP]] as an alternative to using proprietary transport protocols. Often, a streaming transport protocol is used to send video from an event venue to a "[[Cloud computing|cloud]]" transcoding service and CDN, which then uses HTTP-based transport protocols to distribute the video to individual homes and users.<ref>{{cite web|title = Streaming the London Olympic Games with the "Go Live Package" from iStreamPlanet and Haivision {{!}} iStreamPlanet|url = http://www.istreamplanet.com/casestudy/the-london-olympic-games-go-live-package/|website = www.istreamplanet.com|accessdate = 2015-11-11}}</ref> The streaming client (the end user) may interact with the streaming server using a control protocol, such as [[Microsoft Media Server|MMS]] or [[Real Time Streaming Protocol|RTSP]].
==Protocol challenges==
Designing a network protocol to support streaming media raises many problems. [[Datagram]] protocols, such as the [[User Datagram Protocol]] (UDP), send the media stream as a series of small packets. This is simple and efficient; however, there is no mechanism within the protocol to guarantee delivery. It is up to the receiving application to detect loss or corruption and recover data using [[error correction]] techniques. If data is lost, the stream may suffer a [[Dropout (electronics)|dropout]]. The [[Real-time Streaming Protocol]] (RTSP), [[Real-time Transport Protocol]] (RTP) and the [[Real-time Transport Control Protocol]] (RTCP) were specifically designed to stream media over networks. RTSP runs over a variety of transport protocols, while the latter two are built on top of UDP.
Another approach that seems to incorporate both the advantages of using a standard web protocol and the ability to be used for streaming even live content is [[adaptive bitrate streaming]]. HTTP adaptive bitrate streaming is based on HTTP [[progressive download]], but contrary to the previous approach, here the files are very small, so that they can be compared to the streaming of packets, much like the case of using RTSP and RTP.<ref>Ch. Z. Patrikakis, N. Papaoulakis, Ch. Stefanoudaki, M. S. Nunes, "Streaming content wars: Download and play strikes back" presented at the Personalization in Media Delivery Platforms Workshop, [218 – 226], Venice, Italy, 2009.</ref> Reliable protocols, such as the [[Transmission Control Protocol]] (TCP), guarantee correct delivery of each bit in the media stream. However, they accomplish this with a system of timeouts and retries, which makes them more complex to implement. It also means that when there is data loss on the network, the media stream stalls while the protocol handlers detect the loss and retransmit the missing data. Clients can minimize this effect by buffering data for display. While delay due to buffering is acceptable in video on demand scenarios, users of interactive applications such as video conferencing will experience a loss of fidelity if the delay caused by buffering exceeds 200 ms.<ref>Krasic, C. and Li, K. and Walpole, J., ''The case for streaming multimedia with TCP'', Lecture Notes in Computer Science, pages 213--218, Springer, 2001</ref>
[[File:Multicast stream.svg|thumb|Multicasting broadcasts the same copy of the multimedia over the entire network to a group of clients]]
[[Unicast]] protocols send a separate copy of the media stream from the server to each recipient. Unicast is the norm for most Internet connections, but does not scale well when many users want to view the same [[television program]] concurrently. [[Multicast]] protocols were developed to reduce the server/network loads resulting from duplicate data streams that occur when many recipients receive unicast content streams independently. These protocols send a single stream from the source to a group of recipients. Depending on the network infrastructure and type, multicast transmission may or may not be feasible. One potential disadvantage of multicasting is the loss of [[video on demand]] functionality. Continuous streaming of radio or television material usually precludes the recipient's ability to control playback. However, this problem can be mitigated by elements such as caching servers, digital [[set-top box]]es, and buffered [[Media player (application software)|media players]].
[[IP Multicast]] provides a means to send a single media stream to a group of recipients on a [[computer network]]. A multicast protocol, usually [[Internet Group Management Protocol]], is used to manage delivery of multicast streams to the groups of recipients on a LAN. One of the challenges in deploying IP multicast is that routers and firewalls between LANs must allow the passage of packets destined to multicast groups. If the organization that is serving the content has control over the network between server and recipients (i.e., educational, government, and corporate [[intranet]]s), then routing protocols such as [[Protocol Independent Multicast]] can be used to deliver stream content to multiple [[Local Area Network]] segments. As in mass delivery of content, multicast protocols need much less energy and other resources, widespread introduction of reliable multicast (broadcast-like) protocols and their preferential use, wherever possible, is a significant ecological and economic challenge.{{citation needed|date=May 2014}} [[Peer-to-peer]] (P2P) protocols arrange for prerecorded streams to be sent between computers. This prevents the server and its network connections from becoming a bottleneck. However, it raises technical, performance, security, quality, and business issues.
==Applications and marketing==
{{Expand section|date=December 2016}}
Useful – and typical – applications of the "streaming" concept are, for example, long [[video lesson|video lectures]] performed "online" on the Internet.<ref>A typical one-hour [[video lesson|video lecture]] is the following "live stream" from an international conference on [[financial crisis|financial crises]]: [http://videolectures.net/eccs08_stanley_aosptucs/ /videolectures.net]</ref> An advantage of this presentation is that these lectures can be very long, indeed, although they can always be interrupted or repeated at arbitrary places. There are also new marketing concepts. For example, the [[Berlin Philharmonic Orchestra]] sells Internet live streams of whole concerts, instead of several [[CD]]s or similar fixed media, by their so-called "[[Digital Concert Hall]]"<ref>{{cite web|url=http://www.digitalconcerthall.com/|title=The Berliner Philharmoniker’s Digital Concert Hall|website=Digital Concert Hall}}</ref> using [[YouTube]] for "[[trailer (promotion)|trailing]]" purposes only. These "online concerts" are also spread over a lot of different places – cinemas – at various places on the globe. A similar concept is used by the [[Metropolitan Opera]] in New York. Many successful [[startup company|startup]] ventures have based their business on streaming media.<ref>{{cite web |url=https://www.crunchbase.com/category/videostreaming/b1b3b2d785ed2cb1fc603e2b6a3b5ddd |publisher=[[TechCrunch]] |title=Video Streaming Startups |accessdate=2015-03-12}}</ref> There also is [[High Definition Earth Viewing cameras|a livestream]] from the [[International Space Station]].<ref>{{cite web|title=High Definition Earth-Viewing System (HDEV)|url=https://eol.jsc.nasa.gov/ESRS/HDEV/|publisher=NASA|accessdate=26 December 2016}}</ref><ref>{{cite web|title=ISS HD Earth Viewing Experiment|url=http://www.ustream.tv/channel/iss-hdev-payload|accessdate=26 December 2016}}</ref>
==Recording==
Media that is live streamed can be recorded through certain media players such as [[VLC player]], or through the use of a [[Screen Recorder]]. Livestreaming platforms such as [[Twitch.tv|Twitch]] may also incorporate a [[video on demand]] system that allows automatic recording of live broadcasts so that they can be watched later.<ref>{{cite web|url=https://help.twitch.tv/customer/portal/articles/1575302-videos-on-demand|title=Videos On Demand|publisher=}}</ref>
==Copyright==
{{See also|Copyright aspects of downloading and streaming}}
Streaming copyrighted content can involve making infringing copies of the works in question. Streaming, or looking at content on the Internet, is legal in Europe, even if that material is copyrighted.<ref>{{cite web|last1=Smith|first1=Chris|title=Pirating copyrighted content is legal in Europe, if done correctly|url=https://bgr.com/2014/06/05/streaming-movies-and-tv-shows-for-free/|website=bgr.com|publisher=Boy Genius Report|date=5 June 2014}}</ref>
==See also==
{{Portal|Information technology}}
<!-- Please keep entries in alphabetical order & add a short description [[WP:SEEALSO]] -->
{{div col|colwidth=20em}}
* [[Comparison of on-demand music streaming services|Comparison of music streaming systems]]
* [[Comparison of streaming media systems]]
* [[Comparison of video streaming aggregators]]
* [[Comparison of video hosting services]]
* [[Content delivery platform]]
* [[Digital Living Network Alliance]] (DLNA)
* [[Digital television]]
* [[HTTP Live Streaming]]
* [[IPTV]]
* [[List of streaming media systems]]
* [[Live streaming]]
* [[M3U]] playlists
* [[P2PTV]]
* [[Protection of Broadcasts and Broadcasting Organizations Treaty]]
* [[Push technology]]
* [[Real-time data]]
* [[Stream processing]]
* [[Stream recorder]]
* [[Web syndication]]
{{div col end}}
<!-- Please keep entries in alphabetical order & add a short description [[WP:SEEALSO]] -->
==References==
{{Reflist|30em}}
==Further reading==
* J. Preston. "[https://www.nytimes.com/2011/12/12/business/media/occupy-movement-shows-potential-of-live-online-video.html?_r=1&ref=technology Occupy Video Showcases Live Streaming]," New York Times, December 11, 2011
== External links ==
* {{Citation |title=What is Streaming? A high-level view of streaming media technology, history |url=http://www.streamingmedia.com/Articles/ReadArticle.aspx?ArticleID=74052|accessdate=2016-03-25}}
* {{Citation |title=The Early History Of The Streaming Media Industry and The Battle Between Microsoft & Real |url=http://blog.streamingmedia.com/2016/03/history-of-the-streaming-media-industry.html|accessdate=2016-03-25}}
{{Broadcasting}}
{{Web syndication}}
{{Ecommerce}}
[[File:Schou FishCam.jpeg|thumb|lt=A still from a live feed of a fish tank with multiple stream encoding qualities|A still from a [[live stream]] of a fish tank,<ref>{{cite web|url=http://fish.schou.me/|archiveurl=https://archive.today/20141216154536/http://fish.schou.me/|deadurl=yes|title=Schou FishCam|date=16 December 2014|archivedate=16 December 2014|publisher=}}</ref> Schou FishCam]]
'''Streaming media''' is [[multimedia]] that is constantly received by and presented to an [[End-user (computer science)|end-user]] while being delivered by a provider. The verb "to stream" refers to the process of delivering or obtaining media in this manner;{{Clarification needed|date=May 2018}} 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 (software)|media player]] to start playing the [[digital video]] content or listens to [[digital audio]] content before the entire file has been transmitted. Distinguishing delivery method from the media distributed applies specifically to [[telecommunications network]]s, as most of the delivery systems are either inherently streaming (e.g. [[radio]], [[television]], streaming apps) or inherently non-streaming (e.g. [[books]], [[Videotape|video cassettes]], audio [[Compact Disc|CD]]s). 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".
[[Live media|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.
There are challenges with streaming content on the Internet. If the user does not have enough [[Bandwidth (signal processing)|bandwidth]] in their Internet connection, they may experience stops, lags or slow buffering 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 include the [[video sharing website]] [[YouTube]], [[Twitch.tv|Twitch]] and [[Mixer (website)|Mixer]], which live stream the playing of video games; [[Netflix]] and [[Amazon Video]], which stream [[Film|movie]]s and [[Television show|TV show]]s; and [[Spotify]], [[Apple Music]] and [[Tidal (service)|TIDAL]], which stream [[music]].
==History==
In the early 1920s, [[George O. Squier]] was granted [[patent]]s for a system for the transmission and distribution of signals over electrical lines<ref>{{cite web| url = http://www.google.com/patents?id=5pV5AAAAEBAJ&dq=1641608| title = US Patent 1,641,608 | publisher = [[Google Patents]]}}</ref> which was the technical basis for what later became ''[[Muzak Holdings|Muzak]]'', a technology streaming continuous music to commercial customers without the use of [[radio]]. 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: having enough [[CPU]] power and [[bus (computing)|bus]] [[Bandwidth (computing)|bandwidth]] to support the required data rates and creating [[Latency (engineering)|low-latency]] interrupt paths in the [[operating system]] to prevent [[buffer underrun]] and thus enable skip-free streaming of the content. However, computer networks were still limited in the mid-1990s, and audio and video media were usually delivered over non-streaming channels, such as by [[download]]ing a digital file from a remote 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-ROM]]s.
===Late 1990s – early 2000s===
During the late 1990s and early 2000s, users had increased access to computer networks, especially the [[Internet]], and especially during the early 2000s, users had access to increased network [[Bandwidth (signal processing)|bandwidth]], especially in the "[[last mile]]". These technological improvements facilitated the streaming of audio and video content to computer users in their homes and workplaces. As well, there was an increasing use of standard protocols and formats, such as [[Internet protocol suite|TCP/IP]], [[HyperText Transfer Protocol|HTTP]], [[HyperText Markup Language|HTML]] and the Internet became increasingly commercialized, which led to an infusion of investment into the sector. The band [[Severe Tire Damage (band)|Severe Tire Damage]] was the first group to perform live on the Internet. On June 24, 1993, the band was playing a gig at [[PARC (company)|Xerox PARC]] while elsewhere in the building, scientists were discussing new technology (the [[Mbone]]) for broadcasting on the Internet using [[multicasting]]. As proof of PARC's technology, the band's performance was broadcast and could be seen live in Australia and elsewhere. In a March 2017 interview, band member Russ Haines stated that the band had used approximately "half of the total bandwidth of the internet" to stream the performance, which was a 152-by-76 pixel video, updated eight to twelve times per second, with audio quality that was "at best, a bad telephone connection".<ref>[https://www.youtube.com/watch?v=HRa2pE5-Ny0 "History of the Internet Pt. 1 - The First Live Stream"]. ''From YouTube.com.'' Internet Archive - Stream Division. 5 April 2017. Retrieved 2018-01-13.</ref>
[[Microsoft]] Research developed a Microsoft TV application which was compiled under MS Windows Studio Suite and tested in conjunction with Connectix QuickCam. [[RealNetworks]] was also a pioneer in the streaming media markets, when it broadcast a [[baseball]] game between the [[New York Yankees]] and the [[Seattle Mariners]] over the Internet in 1995.<ref>{{cite web |url=http://www.fundinguniverse.com/company-histories/RealNetworks-Inc-Company-History.html |publisher=Funding Universe |title=RealNetworks Inc. |accessdate=2011-07-23}}</ref> The first symphonic concert on the Internet took place at the [[Paramount Theatre (Seattle, Washington)|Paramount Theater]] in [[Seattle]], Washington on November 10, 1995.<ref>{{cite magazine |author=<!--Staff writer(s); no by-line.--> |title= Cyberian Rhapsody |magazine=Billboard |location= United States|publisher= Lynne Segall|date=17 Feb 1996}}</ref> The concert was a collaboration between The Seattle Symphony and various guest musicians such as [[Slash (musician)|Slash]] (Guns 'n Roses, Velvet Revolver), [[Matt Cameron]] (Soundgarden, Pearl Jam), and [[Barrett Martin]] (Screaming Trees). When ''[[Word Magazine]]'' launched in 1995, they featured the first-ever streaming soundtracks on the Internet. {{Citation needed|date=March 2017}}
[[Metropolitan Opera Live in HD]] is a program in which the [[Metropolitan Opera]] streams an [[opera]] performance "live", as the performance is taking place. In 2013–2014, 10 operas were transmitted via satellite into at least 2,000 theaters in 66 countries.<ref>Pamela McClintock, [http://www.hollywoodreporter.com/news/met-opera-standoff-threatens-60-723614 "Met Opera Standoff Threatens $60 Million Theater Business", ''The Hollywood Reporter''] (online), August 7, 2014 on hollywoodreporter.com</ref>
===Etymology===
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]] and later live video on IP networks first by [[Starlight Networks]] for video streaming and [[Real Networks]] for audio streaming; at the time such video was usually referred to as "store and forward video",<ref>{{cite web| url = http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=188525&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel2%2F536%2F4777%2F00188525.pdf%3Farnumber%3D188525| title = On buffer requirements for store-and-forward video on demand service circuits | accessdate =| publisher = [[IEEE]]}}</ref> which was misleading nomenclature.
===Business developments===
The first commercial streaming product appeared in late 1992 and was named StarWorks<ref name="StarWorks">{{cite web |url=https://www.researchgate.net/publication/3556409_StarWorks-a_video_applications_server |title=CompCon Spring 1993-StarWorks-a video applications server}}</ref> and enabled on demand MPEG-1 full motion videos to be randomly accessed on corporate [[Ethernet]] networks. Starworks was from [[Starlight Networks]], who also pioneered live video streaming on Ethernet and via [[Internet Protocol]] over satellites with [[Hughes Network Systems]].<ref name="Starlight Networks and Hughes Network Systems">{{cite web |url=http://www.thefreelibrary.com/Starlight+Networks+and+Hughes+Network+Systems+Plan+Corporate...-a017588314 |title=Starlight Networks and Hughes Network Systems}}</ref> Other early companies who created streaming media technology include [[RealNetworks]] (then known as Progressive Networks) and Protocomm both prior to wide spread World Wide Web usage and once the web became popular in the late 90s, streaming video on the internet blossomed from startups such as VDOnet, acquired by [[RealNetworks]], and Precept, acquired by [[Cisco]].
[[Microsoft]] developed a media player known as [[ActiveMovie]] in 1995 that allowed streaming media and included a proprietary streaming format, which was the precursor to the streaming feature later in [[Windows Media Player]] 6.4 in 1999. In June 1999 [[Apple Inc.|Apple]] also introduced a streaming media format in its [[QuickTime]] 4 application. It was later also widely adopted on websites along with RealPlayer and Windows Media streaming formats. The competing formats on websites required each user to download the respective applications for streaming and resulted in many users having to have all three applications on their computer for general compatibility.
In 2000 Industryview.com launched its "world's largest streaming video archive" website to help businesses promote themselves.<ref>{{cite magazine |last=Hebert |first=Steve |date=November 2000 |title=Streaming Video Opens New Doors |magazine=Videography|page=164}}</ref> Webcasting became an emerging tool for business marketing and advertising that combined the immersive nature of television with the interactivity of the Web. The ability to collect data and feedback from potential customers caused this technology to gain momentum quickly.<ref>{{cite magazine |last=Reinstein |first=Bill |date=25 June 2001 |title=Webcasts Mature as Marketing Tool |magazine=DM News|page=24}}</ref>
Around 2002, the interest in a single, unified, streaming format and the widespread adoption of [[Adobe Flash]] prompted the development of a video streaming format through Flash, which was the format used in Flash-based players on many popular video hosting sites, such as [[YouTube]], now defaulting to [[HTML5 video]].<ref>{{Cite news|url=https://youtube-eng.googleblog.com/2015/01/youtube-now-defaults-to-html5_27.html|title=YouTube now defaults to HTML5 <nowiki><video></nowiki>|last=|first=|date=|work=YouTube Engineering and Developers Blog|access-date=2018-02-20|archive-url=|archive-date=|dead-url=|language=en-US}}</ref> Increasing consumer demand for live streaming has prompted YouTube to implement a new live streaming service to users.<ref>{{cite web |url=http://news.cnet.com/8301-17939_109-9883062-2.html |author=Josh Lowensohn |year=2008 |title=YouTube to Offer Live Streaming This Year |accessdate=2011-07-23}}</ref> Presently the company also offers a (secured) link returning the available connection speed of the user.<ref>{{cite web|url=https://www.youtube.com/my_speed# | title=YouTube Video Speed History |accessdate=April 30, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120426225550/http://www.youtube.com/my_speed |archivedate=April 26, 2012 }}</ref>
The [[Recording Industry Association of America]] (RIAA) revealed through its 2015 earnings report that streaming services were responsible for 34.3 percent of the year's total [[music industry]]'s revenue, growing 29 percent from the previous year and becoming the largest source of income, pulling in around $2.4 billion.<ref>{{cite web|title=News and Notes on 2015 RIAA Shipment and Revenue Statistics|url=https://www.riaa.com/wp-content/uploads/2016/03/RIAA-2015-Year-End-shipments-memo.pdf|publisher=RIAA|accessdate=5 January 2017}}</ref><ref>{{cite web|title=Streaming made more revenue for music industry in 2015 than digital downloads, physical sales|url=http://www.washingtontimes.com/news/2016/mar/23/streaming-made-more-revenue-for-music-industry-in-/|publisher=The Washington Times|accessdate=5 January 2017}}</ref> US streaming revenue grew 57 percent to $1.6 billion in the first half of 2016 and accounted for almost half of industry sales.<ref>{{cite web|last1=Shaw|first1=Lucas|title=The Music Industry Is Finally Making Money on Streaming|url=https://www.bloomberg.com/news/articles/2016-09-20/spotify-apple-drive-u-s-music-industry-s-8-first-half-growth|publisher=Bloomberg|accessdate=5 January 2017|date=20 September 2016}}</ref>
==Use by consumers==
[[File:羽村市動物公園 ニコ生 2017 (32782507624).jpg|left|thumb|Live streaming service at zoo by [[Niconico]]]]
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 device]]s emerged to offer listeners a no-computer option for listening to audio streams. These audio streaming services have become increasingly popular over recent years, as streaming music hit a record of 118.1 billion streams in 2013.<ref>"[https://www.ccianet.org/wp-content/uploads/2014/10/Sky-Is-Rising-2014.pdf The Sky is Rising]", Masnick, M., Ho, M., Hung, J., Beadon, L.. Accessed 8 February 2015.</ref> In general, multimedia content has a large volume, so media storage and transmission costs are still significant. To offset this somewhat, media are generally [[data compression|compressed]] for both storage and streaming. Increasing consumer demand for streaming of [[High definition television|high definition]] (HD) content has led the industry to develop a number of technologies such as [[WirelessHD ]] or [[ITU-T]] [[G.hn]], which are optimized for streaming HD content without forcing the user to install new [[networking cables]]. In 1996, digital pioneer [[Marc Scarpa]] produced the first large-scale, online, live broadcast in history, the [[Adam Yauch]]-led [[Tibetan Freedom Concert]], an event that would define the format of social change broadcasts. Scarpa continued to pioneer in the streaming media world with projects such as [[Woodstock '99]], Townhall with President Clinton, and more recently Covered CA's campaign "Tell a Friend Get Covered" which was live streamed on YouTube.
{{quote box|quote="Streaming creates the illusion—greatly magnified by headphone use, which is another matter—that music is a utility you can turn on and off; the water metaphor is intrinsic to how it works. It dematerializes music, denies it a crucial measure of autonomy, reality, and power. It makes music seem disposable, impermanent. Hence it intensifies the ebb and flow of pop fashion, the way [[List of viral music videos|musical 'memes']] rise up for a week or a month and are then forgotten. And it renders our experience of individual artists/groups shallower."|source=—[[Robert Christgau]], 2018<ref>{{cite web|last=Christgau|first=Robert|authorlink=Robert Christgau|url=http://robertchristgau.com/xgausez.php|title=Xgau Sez|date=November 20, 2018|website=robertchristgau.com|accessdate=November 21, 2018}}</ref>||width=20%|align=right|style=padding:8px;}}
As of 2016, a media stream can be streamed either "live" or "on demand". Live streams are generally provided by a means called "true streaming". True streaming sends the information straight to the computer or device without saving the file to a hard disk. On-demand streaming is provided by a means called ''progressive streaming'' or ''[[progressive download]]''. Progressive streaming saves the file to a hard disk and then is played from that location. On-demand streams are often saved to hard disks and servers for extended amounts of time; while the live streams are only available at one time only (e.g., during the football game).<ref>Grant and Meadows. (2009). Communication Technology Update and Fundamentals 11th Edition. pp.114</ref> Streaming media is increasingly being coupled with use of [[social media]]. For example, sites such as [[YouTube]] encourage social interaction in webcasts through features such as [[live chat]], [[online survey]]s, user posting of comments online and more. Furthermore, streaming media is increasingly being used for [[social business]] and [[e-learning]].<ref>{{cite web|url=http://web.inxpo.com/casting-calls/bid/113793/The-Future-of-Webcasting|title=The Future of Webcasting|last=Kellner|first=Scott|date=28 February 2013|publisher=INXPO|accessdate=15 May 2013|deadurl=yes|archiveurl=https://web.archive.org/web/20130703142337/http://web.inxpo.com/casting-calls/bid/113793/The-Future-of-Webcasting|archivedate=3 July 2013|df=}}</ref> Due the popularity of the streaming medias, many developers have introduced free HD movie streaming apps for the people who use smaller devices such as tablets and smartphones for everyday purposes.
The [[Horowitz Research]] State of Pay TV, OTT and SVOD 2017 report said that 70 percent of those viewing content did so through a streaming service, and that 40 percent of TV viewing was done this way, twice the number from five years earlier. [[Millennials]], the report said, streamed 60 percent of content.<ref>{{cite journal|title=Horowitz: Streaming Is the New Normal|last=Umstead|first=R. Thomas|work=[[Broadcasting & Cable]]|date=5 June 2017|page=4}}</ref>
===Transition from a DVD based to streaming based viewing culture===
One of the movie streaming industry’s largest impacts was on the [[DVD]] industry, which effectively met its demise with the mass popularization of online content. The rise of media streaming caused the downfall of many DVD rental companies such as [[Blockbuster LLC|Blockbuster]]. In July 2015 the [[New York Times]] published an article about [[Netflix]]'s DVD services. It stated that Netflix was continuing their DVD services with 5.3 million subscribers, which was a significant drop from the previous year. On the other hand, their streaming services had 65 million members.<ref>Steel, Emily. Netflix refines it's DVD business, even as streaming unit booms. July 26, 2015. newyorktimes.com. September 29, 2017</ref> In a March 2016 study assessing the “Impact of Movie Streaming over traditional DVD Movie Rental” it was found that respondents did not purchase DVD movies nearly as much anymore, if at all, as streaming had taken over the market. According to the study, viewers did not find movie quality to be significantly different between DVD and online streaming. Issues that respondents believed needed improvement with movie streaming included functions of fast forwarding or rewinding, as well as search functions.<ref name="autogenerated1">{{cite web|url=http://www.jiii.org/uploadfile/2016/0215/20160215101852372.pdf|title=JIII.org|publisher=}}</ref> The article highlighted that the quality of movie streaming as an industry would only increase in time, as advertising revenue continued to soar on a yearly basis throughout the industry, providing incentive for quality content production.<ref name="autogenerated1"/>
==Bandwidth and storage==
[[File:Unicast streaming.svg|thumb|Unicast connections require multiple connections from the same streaming server even when it streams the same content]]
A broadband speed of 2 Mbit/s or more is recommended for streaming [[standard definition]] video without experiencing buffering or skips, especially live video,<ref>{{cite web | url=https://www.broadbandchoices.co.uk/guides/internet/watching-tv-online | title=How to watch live TV online: The complete guide | work=broadbandchoices | date=20 May 2016 | accessdate=1 October 2016 | author=Staples, Kim}}</ref> for example to a [[Roku]], [[Apple TV]], [[Google TV]] or a Sony TV Blu-ray Disc Player. 5 Mbit/s is recommended for High Definition content and 9 Mbit/s for Ultra-High Definition content.<ref>Minimum requirements for Sony TV Blu-ray Disc Player, on advertisement attached to a NetFlix DVD{{Nonspecific|date=March 2011}}</ref> Streaming media storage size is calculated from the streaming bandwidth and length of the media using the following formula (for a single user and file) requires a storage size in [[megabyte]]s which is equal to length (in seconds) × [[bit rate]] (in bit/s) / (8 × 1024 × 1024). For example, one hour of digital video encoded at 300 kbit/s (this was a typical broadband video in 2005 and it was usually encoded in a 320 × 240 pixels window size) will be:
(3,600 s × 300,000 bit/s) / (8×1024×1024) requires around 128 [[Megabyte|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, the requirement is 300 kbit/s × 1,000 = 300,000 kbit/s = 300 Mbit/s of bandwidth. This is equivalent to around 135 [[gigabyte|GB]] per hour. Using a [[multicast]] protocol the server sends out only a single stream that is common to all users. Therefore, such a stream would only use 300 kbit/s of serving bandwidth. See below for more information on these protocols. The calculation for live streaming is similar. Assuming that the seed at the encoder is 500 kbit/s and if the show lasts for 3 hours with 3,000 viewers, then the calculation is number of [[Megabyte|MB]]s transferred = encoder speed (in bit/s) × number of seconds × number of viewers / (8*1024*1024). The results of this calculation are as follows: number of [[Megabyte|MB]]s transferred = 500 x 1024 (bit/s) × 3 × 3,600 ( = 3 hours) × 3,000 (number of viewers) / (8*1024*1024) = 1,977,539 [[Megabyte|MB]]
== Protocols ==
The audio stream is compressed to make the file size smaller using an [[audio coding format]] such as [[MP3]], [[Vorbis]], [[Advanced Audio Coding|AAC]] or [[Opus (audio format)|Opus]]. The video stream is compressed using a [[video coding format]] to make the file size smaller. Video coding formats include [[H.264]], [[High Efficiency Video Coding|HEVC,]] [[VP8]] or [[VP9]]. Encoded audio and video streams are assembled in a container "[[bitstream]]" such as [[MPEG-4|MP4]], [[Flash Video|FLV]], [[WebM]], [[Advanced Systems Format|ASF]] or [[Internet Streaming Media Alliance|ISMA]]. The bitstream is delivered from a streaming server to a streaming client (e.g., the computer user with their [[Internet]]-connected [[laptop]]) using a transport protocol, such as Adobe's [[Real Time Messaging Protocol|RTMP]] or [[Real-time Transport Protocol|RTP]]. In the 2010s, technologies such as Apple's [[HTTP Live Streaming|HLS]], Microsoft's Smooth Streaming, Adobe's HDS and non-proprietary formats such as [[MPEG-DASH]] have emerged to enable [[adaptive bitrate streaming]] over [[HTTP]] as an alternative to using proprietary transport protocols. Often, a streaming transport protocol is used to send video from an event venue to a "[[Cloud computing|cloud]]" transcoding service and CDN, which then uses HTTP-based transport protocols to distribute the video to individual homes and users.<ref>{{cite web|title = Streaming the London Olympic Games with the "Go Live Package" from iStreamPlanet and Haivision {{!}} iStreamPlanet|url = http://www.istreamplanet.com/casestudy/the-london-olympic-games-go-live-package/|website = www.istreamplanet.com|accessdate = 2015-11-11}}</ref> The streaming client (the end user) may interact with the streaming server using a control protocol, such as [[Microsoft Media Server|MMS]] or [[Real Time Streaming Protocol|RTSP]].
==Protocol challenges==
Designing a network protocol to support streaming media raises many problems. [[Datagram]] protocols, such as the [[User Datagram Protocol]] (UDP), send the media stream as a series of small packets. This is simple and efficient; however, there is no mechanism within the protocol to guarantee delivery. It is up to the receiving application to detect loss or corruption and recover data using [[error correction]] techniques. If data is lost, the stream may suffer a [[Dropout (electronics)|dropout]]. The [[Real-time Streaming Protocol]] (RTSP), [[Real-time Transport Protocol]] (RTP) and the [[Real-time Transport Control Protocol]] (RTCP) were specifically designed to stream media over networks. RTSP runs over a variety of transport protocols, while the latter two are built on top of UDP.
Another approach that seems to incorporate both the advantages of using a standard web protocol and the ability to be used for streaming even live content is [[adaptive bitrate streaming]]. HTTP adaptive bitrate streaming is based on HTTP [[progressive download]], but contrary to the previous approach, here the files are very small, so that they can be compared to the streaming of packets, much like the case of using RTSP and RTP.<ref>Ch. Z. Patrikakis, N. Papaoulakis, Ch. Stefanoudaki, M. S. Nunes, "Streaming content wars: Download and play strikes back" presented at the Personalization in Media Delivery Platforms Workshop, [218 – 226], Venice, Italy, 2009.</ref> Reliable protocols, such as the [[Transmission Control Protocol]] (TCP), guarantee correct delivery of each bit in the media stream. However, they accomplish this with a system of timeouts and retries, which makes them more complex to implement. It also means that when there is data loss on the network, the media stream stalls while the protocol handlers detect the loss and retransmit the missing data. Clients can minimize this effect by buffering data for display. While delay due to buffering is acceptable in video on demand scenarios, users of interactive applications such as video conferencing will experience a loss of fidelity if the delay caused by buffering exceeds 200 ms.<ref>Krasic, C. and Li, K. and Walpole, J., ''The case for streaming multimedia with TCP'', Lecture Notes in Computer Science, pages 213--218, Springer, 2001</ref>
[[File:Multicast stream.svg|thumb|Multicasting broadcasts the same copy of the multimedia over the entire network to a group of clients]]
[[Unicast]] protocols send a separate copy of the media stream from the server to each recipient. Unicast is the norm for most Internet connections, but does not scale well when many users want to view the same [[television program]] concurrently. [[Multicast]] protocols were developed to reduce the server/network loads resulting from duplicate data streams that occur when many recipients receive unicast content streams independently. These protocols send a single stream from the source to a group of recipients. Depending on the network infrastructure and type, multicast transmission may or may not be feasible. One potential disadvantage of multicasting is the loss of [[video on demand]] functionality. Continuous streaming of radio or television material usually precludes the recipient's ability to control playback. However, this problem can be mitigated by elements such as caching servers, digital [[set-top box]]es, and buffered [[Media player (application software)|media players]].
[[IP Multicast]] provides a means to send a single media stream to a group of recipients on a [[computer network]]. A multicast protocol, usually [[Internet Group Management Protocol]], is used to manage delivery of multicast streams to the groups of recipients on a LAN. One of the challenges in deploying IP multicast is that routers and firewalls between LANs must allow the passage of packets destined to multicast groups. If the organization that is serving the content has control over the network between server and recipients (i.e., educational, government, and corporate [[intranet]]s), then routing protocols such as [[Protocol Independent Multicast]] can be used to deliver stream content to multiple [[Local Area Network]] segments. As in mass delivery of content, multicast protocols need much less energy and other resources, widespread introduction of reliable multicast (broadcast-like) protocols and their preferential use, wherever possible, is a significant ecological and economic challenge.{{citation needed|date=May 2014}} [[Peer-to-peer]] (P2P) protocols arrange for prerecorded streams to be sent between computers. This prevents the server and its network connections from becoming a bottleneck. However, it raises technical, performance, security, quality, and business issues.
==Applications and marketing==
{{Expand section|date=December 2016}}
Useful – and typical – applications of the "streaming" concept are, for example, long [[video lesson|video lectures]] performed "online" on the Internet.<ref>A typical one-hour [[video lesson|video lecture]] is the following "live stream" from an international conference on [[financial crisis|financial crises]]: [http://videolectures.net/eccs08_stanley_aosptucs/ /videolectures.net]</ref> An advantage of this presentation is that these lectures can be very long, indeed, although they can always be interrupted or repeated at arbitrary places. There are also new marketing concepts. For example, the [[Berlin Philharmonic Orchestra]] sells Internet live streams of whole concerts, instead of several [[CD]]s or similar fixed media, by their so-called "[[Digital Concert Hall]]"<ref>{{cite web|url=http://www.digitalconcerthall.com/|title=The Berliner Philharmoniker’s Digital Concert Hall|website=Digital Concert Hall}}</ref> using [[YouTube]] for "[[trailer (promotion)|trailing]]" purposes only. These "online concerts" are also spread over a lot of different places – cinemas – at various places on the globe. A similar concept is used by the [[Metropolitan Opera]] in New York. Many successful [[startup company|startup]] ventures have based their business on streaming media.<ref>{{cite web |url=https://www.crunchbase.com/category/videostreaming/b1b3b2d785ed2cb1fc603e2b6a3b5ddd |publisher=[[TechCrunch]] |title=Video Streaming Startups |accessdate=2015-03-12}}</ref> There also is [[High Definition Earth Viewing cameras|a livestream]] from the [[International Space Station]].<ref>{{cite web|title=High Definition Earth-Viewing System (HDEV)|url=https://eol.jsc.nasa.gov/ESRS/HDEV/|publisher=NASA|accessdate=26 December 2016}}</ref><ref>{{cite web|title=ISS HD Earth Viewing Experiment|url=http://www.ustream.tv/channel/iss-hdev-payload|accessdate=26 December 2016}}</ref>
==Recording==
Media that is live streamed can be recorded through certain media players such as [[VLC player]], or through the use of a [[Screen Recorder]]. Livestreaming platforms such as [[Twitch.tv|Twitch]] may also incorporate a [[video on demand]] system that allows automatic recording of live broadcasts so that they can be watched later.<ref>{{cite web|url=https://help.twitch.tv/customer/portal/articles/1575302-videos-on-demand|title=Videos On Demand|publisher=}}</ref>
==Copyright==
{{See also|Copyright aspects of downloading and streaming}}
Streaming copyrighted content can involve making infringing copies of the works in question. Streaming, or looking at content on the Internet, is legal in Europe, even if that material is copyrighted.<ref>{{cite web|last1=Smith|first1=Chris|title=Pirating copyrighted content is legal in Europe, if done correctly|url=https://bgr.com/2014/06/05/streaming-movies-and-tv-shows-for-free/|website=bgr.com|publisher=Boy Genius Report|date=5 June 2014}}</ref>
==See also==
{{Portal|Information technology}}
<!-- Please keep entries in alphabetical order & add a short description [[WP:SEEALSO]] -->
{{div col|colwidth=20em}}
* [[Comparison of on-demand music streaming services|Comparison of music streaming systems]]
* [[Comparison of streaming media systems]]
* [[Comparison of video streaming aggregators]]
* [[Comparison of video hosting services]]
* [[Content delivery platform]]
* [[Digital Living Network Alliance]] (DLNA)
* [[Digital television]]
* [[HTTP Live Streaming]]
* [[IPTV]]
* [[List of streaming media systems]]
* [[Live streaming]]
* [[M3U]] playlists
* [[P2PTV]]
* [[Protection of Broadcasts and Broadcasting Organizations Treaty]]
* [[Push technology]]
* [[Real-time data]]
* [[Stream processing]]
* [[Stream recorder]]
* [[Web syndication]]
{{div col end}}
<!-- Please keep entries in alphabetical order & add a short description [[WP:SEEALSO]] -->
==References==
{{Reflist|30em}}
==Further reading==
* J. Preston. "[https://www.nytimes.com/2011/12/12/business/media/occupy-movement-shows-potential-of-live-online-video.html?_r=1&ref=technology Occupy Video Showcases Live Streaming]," New York Times, December 11, 2011
== External links ==
* {{Citation |title=What is Streaming? A high-level view of streaming media technology, history |url=http://www.streamingmedia.com/Articles/ReadArticle.aspx?ArticleID=74052|accessdate=2016-03-25}}
* {{Citation |title=The Early History Of The Streaming Media Industry and The Battle Between Microsoft & Real |url=http://blog.streamingmedia.com/2016/03/history-of-the-streaming-media-industry.html|accessdate=2016-03-25}}
{{Broadcasting}}
{{Web syndication}}
