Inside Corona: Microsoft improves usability and control
Unless you’re in the digital media business, you might not realize how much Microsoft has invested in Windows’ integrated media technologies. Virtually all modern Windows PCs can play back smooth, high-resolution digital video with synchronized sound. For Windows Media 9 Series, formerly code-named Corona, Microsoft reworked its entire media framework — client, server, and SDK — to meet the demands of enterprise and broadband applications. Corona targets major players in the content arena, including Sony, CNN, and Charter Communications.
Its new features are relevant to any business that can use audio or video to communicate with customers, partners, and employees.
We’ve been working with the Corona server components (Windows Media Services) for several weeks as part of our evaluation of Windows .Net Server RC1. The most relevant server-side improvements to Windows’ media architecture fall into two main areas: user experience and control.
From a user’s perspective, streaming video is an imperfect technology. Pauses and gaps in playback are commonplace even on LANs, and everyone has experienced dropped connections that require closing and reopening the stream. Users on broadband and local connections have to wait several seconds for the player’s buffer to load before playback begins. These hassles can make streaming media more trouble than it’s worth.
The new Windows Media Services can ride out network glitches through a number of enhancements. Client-to-server connections are resilient. If a network connection is lost during playback, the Corona client layer negotiates an expedited, transparent reconnect when the circuit comes back up. In most cases, brief connectivity losses will go unnoticed by users. Media Services loads Corona’s larger client buffers at full network speed, regardless of the clip’s playback rate. On a sufficiently fast connection, playback starts immediately after the clip is selected. Buffered data and error correction smooth playback even over error-prone or intermittent (e.g. wireless) links.
The Corona facilities that many record companies will use to protect their music will help other companies control access to confidential information. The Corona architecture restricts and logs clip playback. Server-side user authentication is built into Media Services, and every clip carries a set of policies and permissions that eliminate unauthorized use. The exchange of user credentials is encrypted. Media Services maintains detailed access histories so administrators can monitor delivery and verify security.
Server-side playlists give Media Services unparalleled control over content delivery. An author or administrator can assemble clips on the server and direct that they be played back in a specified order. Users can skip over content only if that right has been granted to them. That feature is meant to support advertising, but it’s just as useful for confidentiality notices, policy education, and other must-view business content.
Windows Services’ support for live streaming events — content that is assembled at the server in real time while it is broadcast to users — is compelling. During a live broadcast, the producer can rearrange and remove material at will, even pre-empting a clip during playback with urgent content. It takes a few seconds for users’ playback buffers to empty before the inserted clip plays, but the process requires no intervention from the user.
Microsoft has elevated Media Services to match the robustness of its client framework. Corona is a far better fit for business, LAN, wireless, and broadband applications than previous media server implementations.
— Tom Yager
