Industry Experts Discuss the Future of MPEG-DASH at NAB

“比什么都重要, DASH实现互操作性,Iraj Sodagar说, 首席多媒体架构师微软和 DASH行业论坛 (DASH-IF)总统. “The whole idea of DASH was gathering the best deployed streaming technologies in the market, 添加更多内容, 并创建互操作性标准."

The first edition of the core standards were published in April 2012, Sodagar指出, 添加, “第二版的MPEG-DASH, 哪一个扩展了第一版的功能, 即将由ISO/IEC发布.Sodagar也是MPEG-DASH子组主席.

Sodagar在DASH会谈期间发表了这些评论, an event that took place last week at the Renaissance Hotel during the NAB conference in Las Vegas, 内华达. Will Law是一名建筑师 Akamai主持讲座. 搭建舞台, Law reminding the audience of the limitations of the traditional player environment before the promise of DASH.

“A content owner today must build and manage 12 or more players to reach the majority of users,Law说. “Flash Player used to provide a single player application platform. 今天，它仍然在台式机/笔记本设备上占据主导地位, 而是不支持Flash的移动设备的兴起, 比如手机和平板电脑, 是否打破了玩家空间.”

Law noted that not only are there different player requirements, but also differing development and player environments.

“Smart televisions all have different application development environments,Law说. “联网设备，比如Roku, 苹果电视, Chromecast, 拥有独立的玩家环境, 以及PS4等游戏机, Xbox一, 任天堂, 需要单独的玩家.”

几位演讲者重点讨论了MPEG-DASH, 作为一个相对较新的标准, needed enhancements to catch up with more proprietary solutions, 即使是基于html5的玩家.

One such area is the use of browser extensions to protect content. 这些组合在一起，被称为加密媒体扩展(EME) which is a W3C standard that's being integrated into the DASH standards. This proposal for EME within DASH extends the HTMLMediaElement by providing APIs to control playback of protected content.

This use of common EMEs is akin to the move to Common Encryption Scheme (CENC) which was rolled into the first edition of the DASH standards. 然而, EMEs offer additional benefits for media services -- such as Adobe Primetime and 微软 Azure Media Services -- which themselves use protected SDKs (PSDKs) to protect content.

“The API supports use cases ranging from simple clear key decryption to high value video given an appropriate user agent implementation,DASH Talks的幻灯片指出. "License/key exchange is controlled by the application, facilitating the development of robust playback applications supporting a range of content decryption and protection technologies.”

Panelists also discussed the inclusion of advertising insertion in DASH. 指状组合型的 Alex Giladi谈到了两种类型的架构, those that are app-driven and those that are server-driven, 以及每个的线性工作流程.

对于应用驱动的模型, Giladi noted that it requires translating an existing workflow into DASH, which is a robust enough set of standards to handle both types of workflows.

“The DASH client 和 ad splicer are modules in the client app,吉拉迪说, noting that DASH events are used to transport cue messages, 包括用户定义的事件作为“定时blob”.”

“Cue events are essential,” one of Giladi’s slides stated. “A DASH client without support for a specific cue format cannot play the content.”

吉拉迪展示了不同类型的提示信息, 包括无处不在的SCTE 35提示信息, 可以在DASH中携带吗.

One hot topic in the DASH Talks and on the NAB show floor was the need for DASH-compliant players. Michael Luby Qualcomm presented two technologies: one forthcoming and one already in place with at least one of Qualcomm’s major OEM customers. The already-implemented technology is an in-silicon DASH client designed as part of Qualcomm’s Long-Term Evolution (LTE) mobile chipsets.

“Our Multicast Service Device Client is compliant with the 3GPP Rel-9 specification, 我们的DASH客户端集成到MSDC,露比说.

The DASH client in MSDC is already on Snapdragon 800 chipsets, 露比:, 添加 that a key selling point for Qualcomm was the tight integration between MSDC 和 Snapdragon LTE modem, including API extensions for obtaining accurate time from network, which is critical in both unicast and multicast environments such as eMBMS.

“We are expanding eMBMS support on all Snapdragon devices with LTE,露比说, 添加 that Korea Telecom launched a commercial LTE/eMBMS service in January 2014. Ongoing trials are continuing in Australia, Europe, 和 United States.

查看完整的DASH演讲.