Adaptive bit rate
Encyclopedia
Adaptive bitrate streaming is a technique used in streaming
multimedia
over computer network
s. While in the past most video streaming technologies utilized streaming protocols such RTP
with RTSP, today's adaptive streaming technologies are almost exclusively based on HTTP and designed to work efficiently over large distributed HTTP networks such as the Internet.
It works by detecting a user's bandwidth and CPU capacity in real time and adjusting the quality of a video stream accordingly. It requires the use of an encoder which can encode a single source video at multiple bit rate
s. The player client switches between streaming the different encodings depending on available resources. "The result: very little buffering, fast start time and a good experience for both high-end and low-end connections."
houses, content delivery network
s and studios use adaptive bit rate technology in order to provide consumers with higher quality video using less manpower and fewer resources. When all is said and done, the creation of multiple video outputs, particularly for adaptive bit rate streaming, adds great value to consumers. If the technology is working as designed, the end user or consumer should be completely unaware of it. Therefore, even though media companies have been actively using adaptive bit rate technology for many years now and it has essentially become a standard practice for high-end streaming providers, mainstream consumers are relatively ignorant of its necessity.
The media and entertainment industry are the main beneficiaries of adaptive bit rate streaming. As the video space grows exponentially, content delivery networks and video providers can provide customers with a superior viewing experience. Adaptive bit rate technology requires less encoding which simplifies overall workflow and creates better results.
A CDN
is often used to deliver media streaming to an Internet audience, as it allows scalability. The CDN receives the stream from the source at its Origin server, then replicates it to many or all of its Edge cache servers. The end-user requests the stream and is redirected to the "closest" Edge server. The use of HTTP-base adaptive streaming allows the Edge server to run a simple HTTP server software, whose licence cost is cheap or free, reducing software licencing cost, compared to costly media server licences (e.g. Adobe Flash Media Streaming Server). The CDN cost for HTTP streaming media is then similar to HTTP web caching CDN cost.
, Apple
, Microsoft
and Octoshape
. In September 2010, Move Networks was awarded a patent for their adaptive bit rate streaming.
) can support. Another major goal of dynamic streaming is to make this process smooth and seamless to users, so that if up-scaling or down-scaling
the quality of the stream is necessary, it is a smooth and nearly unnoticeable switch without disrupting the continuous playback."
The latest versions of Flash Player and Flash Media Server support adaptive bit-rate streaming over the traditional RTMP
protocol, as well as HTTP
, similar to the HTTP-based solutions from Apple and Microsoft. HTTP-based streaming has the advantage of not requiring any firewall ports being opened outside of the normal ports used by web browsers. HTTP-based streaming also allows video fragments to be cached
by browsers, proxies, and CDNs
, drastically reducing the load on the source server.
X, and iPhone
software systems." Apple's iPad
also provides HTTP Live Streaming capabilities. It works by breaking down streams into several small HTTP-based file downloads that load simultaneously at variable adaptive rates.
HTTP Live Streaming is a standard feature in the iPhone 3.0 and newer versions.
HTTP adaptive bit rate 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.
While all adaptive bit-rate streaming solutions are proprietary offerings as of October 2010, Apple has submitted its solution to the IETF for consideration as an Internet standard
.
and standardized by Microsoft as the Protected Interoperable File Format. Microsoft is actively involved with 3GPP
, MPEG and DECE organizations' efforts to standardize adaptive bit-rate HTTP streaming. Microsoft provides Smooth Streaming Client software development kits for Silverlight and Windows Phone 7
, as well as a Smooth Streaming Porting Kit that can be used for other client operating systems, such as Apple iOS, Android, and Linux. IIS Media Services 4.0, released in November 2010, introduced a feature which enables Smooth Streaming H.264/AAC videos, both live and on-demand, to be dynamically repackaged into the Apple HTTP Adaptive Streaming format and delivered to iOS devices without the need for re-encoding.
Microsoft has successfully demonstrated delivery of both live and on-demand 1080p HD video with Smooth Streaming to Silverlight clients. In 2010 Microsoft also partnered with NVIDIA to demonstrate live streaming of 1080p stereoscopic 3D video to PCs equipped with NVIDIA 3D Vision
technology.
The adaptation logic is implemented at the server. This has a clear advantage: when a new version of the adaptation logic is developed only the servers need to be updated. A demo is here.
Streaming media
Streaming media is multimedia that is constantly received by and 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...
multimedia
Multimedia
Multimedia is media and content that uses a combination of different content forms. The term can be used as a noun or as an adjective describing a medium as having multiple content forms. The term is used in contrast to media which use only rudimentary computer display such as text-only, or...
over computer network
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
s. While in the past most video streaming technologies utilized streaming protocols such RTP
Real-time Transport Protocol
The Real-time Transport Protocol defines a standardized packet format for delivering audio and video over IP networks. RTP is used extensively in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applications, television services and...
with RTSP, today's adaptive streaming technologies are almost exclusively based on HTTP and designed to work efficiently over large distributed HTTP networks such as the Internet.
It works by detecting a user's bandwidth and CPU capacity in real time and adjusting the quality of a video stream accordingly. It requires the use of an encoder which can encode a single source video at multiple bit rate
Bit rate
In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....
s. The player client switches between streaming the different encodings depending on available resources. "The result: very little buffering, fast start time and a good experience for both high-end and low-end connections."
Current uses
Post-productionPost-production
Post-production is part of filmmaking and the video production process. It occurs in the making of motion pictures, television programs, radio programs, advertising, audio recordings, photography, and digital art...
houses, content delivery network
Content Delivery Network
A content delivery network or content distribution network is a system of computers containing copies of data placed at various nodes of a network....
s and studios use adaptive bit rate technology in order to provide consumers with higher quality video using less manpower and fewer resources. When all is said and done, the creation of multiple video outputs, particularly for adaptive bit rate streaming, adds great value to consumers. If the technology is working as designed, the end user or consumer should be completely unaware of it. Therefore, even though media companies have been actively using adaptive bit rate technology for many years now and it has essentially become a standard practice for high-end streaming providers, mainstream consumers are relatively ignorant of its necessity.
Benefits of adaptive bit rate streaming
Consumers of streaming media experience the highest quality material when adaptive bit rate streaming is used because the user's network and playback conditions are automatically adapted to at any given time under changing conditions.The media and entertainment industry are the main beneficiaries of adaptive bit rate streaming. As the video space grows exponentially, content delivery networks and video providers can provide customers with a superior viewing experience. Adaptive bit rate technology requires less encoding which simplifies overall workflow and creates better results.
A CDN
Content Delivery Network
A content delivery network or content distribution network is a system of computers containing copies of data placed at various nodes of a network....
is often used to deliver media streaming to an Internet audience, as it allows scalability. The CDN receives the stream from the source at its Origin server, then replicates it to many or all of its Edge cache servers. The end-user requests the stream and is redirected to the "closest" Edge server. The use of HTTP-base adaptive streaming allows the Edge server to run a simple HTTP server software, whose licence cost is cheap or free, reducing software licencing cost, compared to costly media server licences (e.g. Adobe Flash Media Streaming Server). The CDN cost for HTTP streaming media is then similar to HTTP web caching CDN cost.
Implementations
Adaptive bit rate streaming was conceptualized by Move Networks and is now being developed and utilized by Adobe SystemsAdobe Systems
Adobe Systems Incorporated is an American computer software company founded in 1982 and headquartered in San Jose, California, United States...
, Apple
Apple Computer
Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...
, Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
and Octoshape
Octoshape
Octoshape is a proprietary streaming media platform. It uses throughput optimization technology to deliver HD quality streams and to break through congestion in the last mile to provide more resilient delivery...
. In September 2010, Move Networks was awarded a patent for their adaptive bit rate streaming.
Adobe Dynamic Streaming for Flash
"Dynamic streaming is the process of efficiently delivering streaming video to users by dynamically switching among different streams of varying quality and size during playback. This provides users with the best possible viewing experience their bandwidth and local computer hardware (CPUCentral processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
) can support. Another major goal of dynamic streaming is to make this process smooth and seamless to users, so that if up-scaling or down-scaling
Video scaler
A video scaler is a device for converting video signals from one size or resolution to another: usually "upscaling" or "upconverting" a video signal from a low resolution to one of higher resolution A video scaler is a device for converting video signals from one size or resolution to another:...
the quality of the stream is necessary, it is a smooth and nearly unnoticeable switch without disrupting the continuous playback."
The latest versions of Flash Player and Flash Media Server support adaptive bit-rate streaming over the traditional RTMP
Real Time Messaging Protocol
Real Time Messaging Protocol was initially a proprietary protocol developed by Macromedia for streaming audio, video and data over the Internet, between a Flash player and a server...
protocol, as well as HTTP
Hypertext Transfer Protocol
The Hypertext Transfer Protocol is a networking protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web....
, similar to the HTTP-based solutions from Apple and Microsoft. HTTP-based streaming has the advantage of not requiring any firewall ports being opened outside of the normal ports used by web browsers. HTTP-based streaming also allows video fragments to be cached
Web cache
A web cache is a mechanism for the temporary storage of web documents, such as HTML pages and images, to reduce bandwidth usage, server load, and perceived lag...
by browsers, proxies, and CDNs
Content Delivery Network
A content delivery network or content distribution network is a system of computers containing copies of data placed at various nodes of a network....
, drastically reducing the load on the source server.
Apple HTTP Adaptive Streaming for iPhone/iPad
"HTTP Live Streaming is an HTTP-based media streaming communications protocol implemented by Apple Inc. as part of their QuickTimeQuickTime
QuickTime is an extensible proprietary multimedia framework developed by Apple Inc., capable of handling various formats of digital video, picture, sound, panoramic images, and interactivity. The classic version of QuickTime is available for Windows XP and later, as well as Mac OS X Leopard and...
X, and iPhone
IPhone
The iPhone is a line of Internet and multimedia-enabled smartphones marketed by Apple Inc. The first iPhone was unveiled by Steve Jobs, then CEO of Apple, on January 9, 2007, and released on June 29, 2007...
software systems." Apple's iPad
IPad
The iPad is a line of tablet computers designed, developed and marketed by Apple Inc., primarily as a platform for audio-visual media including books, periodicals, movies, music, games, and web content. The iPad was introduced on January 27, 2010 by Apple's then-CEO Steve Jobs. Its size and...
also provides HTTP Live Streaming capabilities. It works by breaking down streams into several small HTTP-based file downloads that load simultaneously at variable adaptive rates.
HTTP Live Streaming is a standard feature in the iPhone 3.0 and newer versions.
HTTP adaptive bit rate streaming is based on HTTP progressive download
Progressive download
Progressive download is a term used to describe the transfer of digital media files from a server to a client, typically using the HTTP protocol when initiated from a computer. The consumer may begin playback of the media before the download is complete...
, 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.
While all adaptive bit-rate streaming solutions are proprietary offerings as of October 2010, Apple has submitted its solution to the IETF for consideration as an Internet standard
Internet standard
In computer network engineering, an Internet Standard is a normative specification of a technology or methodology applicable to the Internet. Internet Standards are created and published by the Internet Engineering Task Force .-Overview:...
.
Microsoft Smooth Streaming
Smooth Streaming is an IIS Media Services extension that enables adaptive streaming of media to clients over HTTP. The format specification is based on the ISO Base Media File FormatISO base media file format
ISO base media file format defines a general structure for time-based multimedia files such as video and audio. It is used as the basis for other media file formats...
and standardized by Microsoft as the Protected Interoperable File Format. Microsoft is actively involved with 3GPP
3GPP
The 3rd Generation Partnership Project is a collaboration between groups of telecommunications associations, known as the Organizational Partners...
, MPEG and DECE organizations' efforts to standardize adaptive bit-rate HTTP streaming. Microsoft provides Smooth Streaming Client software development kits for Silverlight and Windows Phone 7
Windows Phone 7
Windows Phone is a mobile operating system developed by Microsoft, and is the successor to its Windows Mobile platform, although incompatible with it. Unlike its predecessor, it is primarily aimed at the consumer market rather than the enterprise market...
, as well as a Smooth Streaming Porting Kit that can be used for other client operating systems, such as Apple iOS, Android, and Linux. IIS Media Services 4.0, released in November 2010, introduced a feature which enables Smooth Streaming H.264/AAC videos, both live and on-demand, to be dynamically repackaged into the Apple HTTP Adaptive Streaming format and delivered to iOS devices without the need for re-encoding.
Microsoft has successfully demonstrated delivery of both live and on-demand 1080p HD video with Smooth Streaming to Silverlight clients. In 2010 Microsoft also partnered with NVIDIA to demonstrate live streaming of 1080p stereoscopic 3D video to PCs equipped with NVIDIA 3D Vision
Nvidia 3D Vision
3D Vision is a stereoscopic gaming kit from Nvidia which consists of LC shutter glasses and driver software which enables stereoscopic vision for any Direct3D game, with various degrees of compatibility...
technology.
Octoshape Multi-BitRate
Octoshape supports automatic multi-bit rate streaming using standard streaming formats like Flash, Windows and HLS inputs. Octoshape uses a unique throughput optimization technology and resilient coding schemes to maximize the throughput consistency of a video stream over the Internet. Octoshape supports shifting to the appropriate bit rate of the particular consumer of the video. However, the core transport provides for a stable throughput profile over the Internet unlike TCP based technologies like HTTP or RTMP that have variable throughput profiles based on packet loss and latency. The technology selects appropriate bit rates instantly on startup, but rarely makes use of the rate shifting technology during a viewing session, giving the consumer a consistent TV quality video experience. Octoshape is also the first technology to deploy automatic multi-bit rate technology along with Multicast transport over the public Internet.Quavlive Adaptive Live Streaming
Quavlive Adaptive Streaming is a live adaptive streaming that supports the new WebM codec and H264 codec. It implements the stream-switching technique and support a configurable number of video bitrates.The adaptation logic is implemented at the server. This has a clear advantage: when a new version of the adaptation logic is developed only the servers need to be updated. A demo is here.