2012年11月12日
By 蒂姆Siglin 特约编辑
专题文章

Wowza Media Server.5 Includes Support for 字幕, 代码转换器覆盖, and 更多的

在上个月的视频基础设施峰会 (VIS)在伦敦, both RealNetworks and Wowza allowed me to provide a "sneak peek" at a few features for their soon-to-be-launched media server upgrades. 真正的启动螺旋通用媒体服务器的v15版本上周，Wowza发布了第三版.Wowza媒体服务器的5号服务器.

The "sneak peek" at the Europe event only listed bullet points on a number of features, but with the launch Wowza announces a bit more detail around three features: closed captioning, HTTP的起源, 转码器叠加.

字幕

根据Wowza的说法 Media vice-president of product management Chris Knowlton, 这是一个非常需要的功能. As mentioned by a Real representative during the VIS panel, this feature has always been a bit of a black art when it comes to media servers. While we've had options like SMIL and timed-text for well over 14 years, there really have been no true closed-captioning standards implementations until earlier this year.

Knowlton says Wowza seeks to address that issue by supporting both 508a- and 608a-compliant closed captioning for live and on-demand video streams in Wowza Media Server.5.

HTTP的起源

多年来, customers have been able to use Wowza Media Server in an origin-edge configurations for RTMP live and on-demand streaming. Yet with the advent of adaptive bitrate (ABR) content segmentation for delivery via HTTP—Adobe HLS, 苹果HLS, or 微软 Smooth Streaming—there's been no way in Wowza Media Server to deliver HTTP ABR content directly into caching networks such as most CDNs.

“主要原因是,Wowza首席技术专家查理·古德说, "was that each Wowza URL contained a unique session ID that would 'bust' the downstream caches. The reason was our ability to uniquely address an HTTP fragment or “chunk” to a specified user and user session. 使用WMS 3.5, when in HTTP的起源 mode, we change the URL structure to eliminate this issue."

“这修改,戴夫·斯图本沃尔补充道, Wowza首席执行官, "allows any CDN or enterprise caching network to accept and cache HTTP streams from Wowza Media Server and make full use of their HTTP caching, 扩展, 以及加速能力."

代码转换器覆盖

根据Wowza的说法, the transcoder add-on (one of more than 20 add-on modules Wowza offers) has been a success. The company is moving to normalize pricing across a number of its premium add-ons, dropping the price of the transcoder add-on in the process. 同时, Wowza is adding an additional tool to the add-on in the form of transcoder overlays.

"The Transcoder has a new, comprehensive overlay capability,诺尔顿说. "Transcoder can now do crawls, bugs, and logos, without the need for an internal encoder."

Stubenvoll also pointed out that the transcoder add-on offers limited aggregate advertising opportunities, given the ability to separate the video fragmentation from the overlay capabilities.

"Since Transcoder handles integration of the graphic overlay on top of the video stream,他说, "we think Transcoder will find its way into the toolkit of many Wowza Media Server users."

最后, one other topic of note: A number of media server vendors, 包括Wowza, have made noise recently about their server's ability to saturate a 10Gbps port. While this isn't typical of small media server deployments, it is a benefit to those who use media servers in enterprise clusters or content delivery network (CDN) configurations.

Wowza的诺尔顿说wms3.5能够饱和一个10Gbps的网络端口, but that most customers won't be pushing it quite to that level of saturation.

"We have anecdotal 信息 from customers that [10Gbps saturation] can be accomplished using either dual quad-core or hex-core Xeon processors with 16-32 GB of RAM,诺尔顿说. "But note that most high-volume customers that would try this during testing are more likely to run at an actual load of less than 8 Gbps, 为交通高峰预留空间."

I asked Knowlton if there was a way to test saturation in Transitions' lab, since we have a quad-core Xeon and and 10G physical plant. When asked whether there is a particular tool Wowza recommends for the 8-10Gbps test, Knowlton said there is an RTMP-based tool Wowza offers for load testing.

"There is an RTMP load testing tool for Wowza Media Server.x,诺尔顿说, adding that it's available on a Wowza论坛.