HTTP Streaming bar BoF, IETF 79th HTTP Streaming Survey and Gap Analysis Ning Zong draft-zong-httpstreaming-gap-analysis-01

HTTP Streaming bar BoF, IETF 79th Outline A brief survey of existing HTTP streaming standards and implementations. A brief summary of the existing work. The gap between existing work and possible working scope in IETF.

HTTP Streaming bar BoF, IETF 79th 3GPP: Adaptive HTTP Streaming (AHS) Defines Media Presentation Description (MPD) to characterize the structure and features of a media presentation. Some important elements in a MPD include:  multiple "Period" element;  multiple "Representation" element;  "bandwidth" attribute in “Representation”;  "startWithRAP" attribute in “Representation”;  "qualityRanking" attribute in “Representation”;  "TrickMode" element in “Representation”;  "SegmentInfo" element;  "duration" attribute in “SegmentInfo”;  “URLtemplate“ element, or "Url" elements in “SegmentInfo”; Media Presentation

HTTP Streaming bar BoF, IETF 79th 3GPP: Adaptive HTTP Streaming (AHS) MPD Generating a list of URI pointed to the segments Client Server Segment request Segment Segment request Segment MPD Update

HTTP Streaming bar BoF, IETF 79th Open IPTV Forum (OIPF): HTTP Adaptive Streaming Technical Specification has been published and includes "HTTP Adaptive Streaming”, which adopts 3GPP AHS as basis and adds support for MPEG-2 Transport Stream.

HTTP Streaming bar BoF, IETF 79th MPEG: HTTP Streaming of MPEG Media A series of proposals have been proposed to address the background, objectives, use cases and requirements of the transport of MPEG media over HTTP. The IETF has received from MPEG two liaison statements for our information. No actions from the IETF side are requested or required. Both statements will appear shortly on the IETF's liaison website

HTTP Streaming bar BoF, IETF 79th W3C:Video related work Focus on client implementation built into browser, e.g.,  video playback support using script and html,  push notification support using API,  video support using Media fragments URI.  Websocket API

HTTP Streaming bar BoF, IETF 79th Microsoft: Smooth Streaming Defines each chunk as an MPEG-4 fragment box and stores it within a contiguous MP4 file for easy random access. The MP4 files are classified into two kinds. One is *.ismv file containing video and audio. Another is *.isma containing audio only. Server manifest file (*.ism) describes the relationships between the media tracks, bit rates and files on disk. Client manifest file (*.ismc) describes the available streams to the client: the codecs used, bit rates encoded, video resolutions, markers, captions, etc. Client requests fragments by URL including quality level and fragment offset. Server looks up the MP4 file and figures out which fragment box corresponds to the requested offset. Server extracts the fragment box and sends it over the wire to the client.

HTTP Streaming bar BoF, IETF 79th Adobe: Dynamic HTTP Streaming File packagers translates either on-demand media files or ingested live streams over Real Time Messaging Protocol (RTMP) into fragments and writes the fragments to F4F files. The F4M manifest file format contains information includes codecs, resolutions, and the availability of files encoded at multiple bit rates.

HTTP Streaming bar BoF, IETF 79th Apple: HTTP Live Streaming Stream segmenter reads the Transport Stream from the local network and divides it into a series of small media files (.ts files) of equal duration, and creates an index file containing a play-list of the media files, as well as meta-data information. The index file is in.M3U8 format.

HTTP Streaming bar BoF, IETF 79th Summary of Existing Work manifest Produce segment files and manifest Server Client Segment request Segment Stream segmenter Construct URIs pointed to the segment files Choose file to be requested based on adaptation Look up segment file Continue requesting … … Intermediary Nodes All the intelligence in current HTTP streaming design resides on the server and client software, rather than the network transport.

HTTP Streaming bar BoF, IETF 79th Gap Analysis CharacteristicIf satisfied by existing work Adaptation bit-rateYes Playback controlYes Use existing cache, CDNYes client pull modelYes server push modelNo Reliable transmission in networkYes Real-time support in networkNo QoE improvement (e.g. startup)No QoE monitoringNo More intermediary node supportNo Multicast support for scalabilityNo Based on the above gap list, we can discuss more about the potential working scope in IETF to improve the transport part of HTTP streaming system.

HTTP Streaming bar BoF, IETF 79th Thank you

HTTP Streaming bar BoF, IETF 79th References 3GPP:   OIPF  pdf pdf MPEG   W3C    Microsoft  Adobe  Apple  HTTPStreamingArchitecture/HTTPStreamingArchitecture.html HTTPStreamingArchitecture/HTTPStreamingArchitecture.html 