Flash和Silverlight，终于在一起了

As a first step toward the long-anticipated benefits of H.264 support in both Adobe's Flash and Microsoft's Silverlight platforms, Wowza Media Systems has begun demonstrating its Wowza Media Server Pro Advanced at the National Association of Broadcasters show in Las Vegas, 一直持续到4月23日.

Wowza was one of the first companies to provide an alternative to the Flash Media Server, 目前已售出20多台,000个产品许可, including Wowza Media Server Pro and Wowza Media Server Pro Unlimited with MPEG-TS, 后者和H。.264服务器，通过高清晰度H.264 MPEG transport streams through to broadcast and over-the-air (OTA) solutions, while simultaneously providing a standard-definition H.264 stream that can be delivered via RTMP to Flash players.

"We've used a show like NAB in the past to demonstrate the benefits of H.264 MPEG-TS, as it enhances a broadcaster's existing H.264年基础设施,大卫·斯图本沃尔说, Wowza的首席执行官兼联合创始人, "so the first demonstrations of Advanced server at NAB are a natural fit, as broadcasters look beyond Flash-only delivery to a variety of delivery platforms."

使用高级版本, 哪一个将在2009年下半年发布, Wowza seeks to expand its protocol transfer capabilities beyond OTA and Flash.

"We are confident all of our customers will see immediate benefit from Wowza Media Server Pro Advanced, 不仅仅是广播客户,斯图本沃尔说. "As the industry's first multi-protocol media streaming platform that combines Flash, Silverlight, iPhone, RTSP和RTP, 和MPEG-TS兼容流在一个单一的服务器, H有各种各样的用例.264支持所有这些平台."

Wowza's servers do not provide encoding or transcoding; instead, relying on hardware H.来自Hai Vision等公司的264编码器, as well as software encoders such as Flash Media Encoder, Wowza provides a clearinghouse approach in which an H.264 stream is unbundled from a particular protocol "wrapper" and then transfered to a new protocol.

"We've been doing protocol transfer for quite some time,斯图本沃尔说, 所以新服务器处理任何H.264 content that is thrown at it - from RTP/RTSP to Adobe's RTMP and even transport streams. 这允许任何兼容的H.264编码器服务于多种平台, without requiring the encoder to encode in every single protocol."

This reliance on external encoders also allows the Advanced server to provide Smooth Streaming, Microsoft's dynamic streaming protocol which allows multiple streams at various bitrates to be encoded in to two-second content chunks, with the server determining which stream at a particular bandwidth is best served to the end viewer. Wowza says this Smooth Streaming feature will be available for both live and on-demand content.

"While we've looked at the option of providing trans-rating within Wowza servers,斯图本沃尔说, referring to the conversion of a single high-bitrate stream in to a number of lower bitrate streams," we find that most of our server customers already have multiple encoders, 每个比特率对应一个."

When asked about the practice that some CDNs are trending toward, where virtualization is used to provide multiple servers, 例如Windows Media和Flash, 在同一个物理盒子上, Stubenvoll said he felt Wowza's approach was more sustainable.

"The differences of price - since one would have to have a Windows server license on the virtual machine - as well as performance are what really differentiate our Advanced server from a virtualized approach,斯图本沃尔说. "Some of the CDNs pitching virtualization to their customers are themselves Wowza customers, and we think they will also see the price and performance benefits as we roll out the preview versions of Advanced in a few weeks' time."

当被问及定价时, Stubenvoll would only say that pricing will be available within a few weeks, 在预览版发布时. He mentioned the new Advanced server will be priced somewhere between the Wowza Pro server and the Wowza Media Server Pro Unlimited with MPEG-TS, 哪个卖995美元，哪个卖1美元,995, 分别.

与此同时, Wowza has lowered the price of the MPEG-TS version and is also offering a free upgrade to anyone purchasing the Unlimited version of the server, noting in an earlier press release that "all purchases of Wowza Media Server Pro Unlimited editions after April 8, 2009 are eligible for a free upgrade to Wowza Media Server Pro Advanced."

Wowza的定价, which was lowered shortly before Adobe announced its price drops for Flash Media Server last year, 给Adobe带来了一点挑战. Given Stubenvoll's comments on the pricing range for the Advanced server, at a price point below Adobe's average Flash Media Server pricing, 给Adobe带来了另一个有趣的挑战.

Wowza提供H.264交付的替代方案, the question of whether Adobe will push its prices down even further, as well as Microsoft's positioning as it seeks to integrate H.264 further in to Silverlight via the Silverlight 3 beta, is a question we'll explore later this week in a 流媒体 podcast, 直接从NAB展示厅.