Dynamic Adaptive Streaming over HTTP

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Dynamic Adaptive Streaming over HTTP ( DASH ), also known as MPEG-DASH , enables high-quality streaming media content via the Internet by conventional HTTP - web server .

functionality

Similar to Apple's solution, HTTP Live Streaming (HLS), MPEG-DASH works by breaking down the content into a sequence of small HTTP-based file segments, each segment containing a short section of the total playing time of a media object, potentially several hours in duration. for example a film or the live broadcast of a sports event. The content is provided in a selection of different bit rates, i.e. alternative, content-related sections that are coded with different bit rates. When content is played back by an MPEG DASH client, it automatically selects the one that is suitable for the current connection conditions from the alternatives offered for the next section. The client selects the segment with the highest possible bit rate that can be transmitted in the time available before playback without the playback stalling and having to be buffered again. This enables a DASH client to adapt seamlessly to changing network conditions and guarantee high-quality, smooth playback.

MPEG-DASH is the first bit rate adaptive HTTP-based streaming solution to become an international standard.

MPEG-DASH uses the widespread HTTP web server infrastructure that is used to deliver all types of Internet content. It enables devices such as televisions with Internet access, add-on TV devices, desktop computers, smartphones, tablet computers to access multimedia content (video, TV, radio) delivered via the Internet and, thanks to adaptive streaming technology, to cope with changing reception conditions. The standardization of a solution for adaptive streaming should provide trust in the market for universal applicability, compared to similar, more provider-dependent solutions such as HLS from Apple, Smooth Streaming from Microsoft or HDS from Adobe.

standardization

DASH was developed by MPEG . Work on DASH began in 2010, and in January 2011 it became the official draft of an international standard, which was adopted as a standard in November 2011. The DASH standard was published in April 2012 as ISO / IEC 23009-1: 2012.

DASH is technically related to Adobe Inc. 's HTTP Dynamic Streaming , Apple's HTTP Live Streaming (HLS), and Microsoft's Smooth Streaming . DASH is based on Adaptive HTTP streaming (AHS) from 3GPP Release 9 and on HTTP Adaptive Streaming (HAS) from Open IPTV Forum Release 2. As part of their collaboration with MPEG, 3GPP Release 10 adopted DASH (with certain codecs and operating modes) for use over wireless networks.

overview

DASH is a bit rate adaptive streaming technique in which a multimedia file is divided into one or more segments and delivered to a client via HTTP . A media presentation description (MPD) describes segment information (timing, URL , media properties such as video resolution and bit rates ). Segments can contain any media data, with the specification giving certain recommendations and formats for use with two types of container formats, the MPEG-4 file format or the MPEG-2 transport stream .

DASH is (audio / video) codec agnostic. One or more representations of multimedia files are typically available (i.e. versions with different resolutions or bit rates), and a selection can be made based on the connection situation, device capabilities and user settings, thereby achieving bit rate-adaptive streaming and quality of experience fairness . DASH is also agnostic about the underlying protocol at the application layer. This means that DASH can be used with any protocol, such as DASH via CCN.

Implementations

Client implementations for desktop computers are the DASH-VLC module from the Institute of Information Technology (ITEC) of the Alpen-Adria-Universität Klagenfurt, the open source DASH client library libdash from the Austrian company bitmovin , the multimedia framework from the GPAC group of Télécom ParisTech and the client of the German company castLabs . Content creation is possible with the MP4Box from GPAC or with the wrapper tool “DASHEncoder” (also from ITEC). The FFMPEG open source project also offers the option of creating DASH streams in accordance with ISO / IEC 23009-1: 2014. The first DASH server and Android (2.2 to 4.x) SDK player implementation was demonstrated by RealNetworks at IBC 2012 with the Helix Universal Server and the Helix SDK for Android, as a demonstration of the commercially available delivery from November 2012 - and playback formats with MPEG2-TS (Smart TV) and ISO BMFF (MP4 smartphone, tablet). The open source library libdash is platform-independent and can therefore run on mobile platforms such as Android, iOS and Windows Phone.

Google's YouTube experimented with server-side support for MPEG-DASH. Google Chrome supports it on the client side. Several DASH data sets are offered by the Institute of Information Technology (ITEC) of the Alpen-Adria-Universität Klagenfurt and the GPAC group of Télécom ParisTech . ITEC also offers a verification service for MPEG-DASH-Media-Presentation-Description-Files (MPD).

DASH is possible on the web using HTML5 Media Source Extentions (MSE) and JavaScript-based players. There are open source projects such as B. dash.js from DASH Industry Forum, but also products such as bitdash (for HTML5 with JavaScript as well as Flash, if there is no support for the HTML5 MSE).

Web links

swell

  1. ↑ a b MPEG ratifies its draft standard for DASH , MPEG. December 2, 2011. Archived from the original on August 20, 2012 Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . Retrieved August 26, 2012. @1@ 2Template: Webachiv / IABot / mpeg.chiariglione.org 
  2. ↑ HTTP streaming of MPEG media - blog entry
  3. ↑ ISO / IEC DIS 23009-1.2 Dynamic adaptive streaming over HTTP (DASH)
  4. ↑ ISO / IEC 23009-1: 2012
  5. ↑ a b Updates on DASH - blog entry
  6. ↑ a b ETSI 3GPP 3GPP TS 26.247; Transparent end-to-end packet-switched streaming service (PSS); Progressive Download and Dynamic Adaptive Streaming over HTTP (3GP-DASH)
  7. ↑ Open IPTV Forum Solution Specification Volume 2a - HTTP Adaptive Streaming V2.1 ( Memento of the original from October 9, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.oipf.tv
  8. ↑ Overview of Dynamic Adaptive Streaming over HTTP (DASH)
  9. ↑ C. Timmerer, C. Mueller: DASH Overview
  10. ↑ 3GPP Dynamic Adaptive Streaming over HTTP - Standards and Design Principles ( Memento of the original from August 5, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. by T. Stockhammer @1@ 2Template: Webachiv / IABot / www.mmsys.org
  11. ↑ scholar.google.com/citations
  12. ↑ Y. Liu, J. Geurts, J.-P. Point, S. Lederer, B. Rainer, C. Mueller, C. Timmerer and H. Hellwagner, “Dynamic Adaptive Streaming over CCN: A Caching and Overhead Analysis”, In Proceedings of the IEEE International Conference on Communication (ICC) 2013 - Next-Generation Networking Symposium, Budapest, Hungary, June, 2013
  13. ↑ a b c DASH at ITEC, VLC Plugin, DASHEncoder and Dataset by C. Mueller, S. Lederer, C. Timmerer
  14. ↑ C. Müller and C. Timmerer, “A VLC Media Player Plugin enabling Dynamic Adaptive Streaming over HTTP”, In Proceedings of the ACM Multimedia 2011, Scottsdale, Arizona, November 28, 2011. (PDF; 872 kB)
  15. ↑ a b libdash: Open-source DASH client library by bitmovin
  16. ↑ a b c GPAC Télécom ParisTech ( Memento of the original from February 24, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / gpac.wp.institut-telecom.fr
  17. ^ A b S. Lederer, C. Mueller and C. Timmerer, "Dynamic Adaptive Streaming over HTTP Dataset", In Proceedings of the ACM Multimedia Systems Conference 2012, Chapel Hill, North Carolina, February 22-24, 2012. (PDF; 1.3 MB)
  18. ↑ ISO / IEC 23009-1: 2014. International Organization for Standardization, May 1, 2014, accessed July 3, 2018 .
  19. ↑ FFmpeg Formats Documentation. Retrieved July 3, 2018 .
  20. ↑ Streaming Media and RTOS: MPEG-DASH Support in Youtube
  21. ↑ Chromium Issue 109652: Support MPEG-DASH
  22. ↑ S. Lederer, C. Mueller, C. Timmerer, C. Concolato, J. Le Feuvre and K. Fliegel, Distributed DASH Dataset, In Proceedings of the ACM Conference on Multimedia Systems (ACM MMSys) 2013, Oslo, Norway, 2013 .
  23. ↑ HTML5 MSE
  24. ↑ DASH.JS on Github
  25. ↑ bitdash MPEG-DASH Player (HTML5 & Flash) www.dash-player.com