Using Play While Archiving
The Play While Archiving feature enables you to use a partially-archived file from a broadcast publishing point as a source for a different publishing point. This means that while a broadcast is being archived, you can create an on-demand or broadcast publishing point and stream that partially-archived file to users. This lets them start viewing the broadcast without having to wait until the file is completely written by the WMS Archive Data Writer plug-in. A partially-archived file can be used as a source 60 seconds after archiving has started.
The other main advantage of Play While Archiving is allowing cache proxy servers to begin streaming content to customers without having to wait until the content is completely cached from the origin server. To enable this scenario, the cache proxy plug-in on the cache proxy server must recognize that a client request for the partially-cached content is a cache hit.
Note
When a Windows Media Player 6.4 client or a Windows CE device client connects to your cache proxy server, the cache proxy plug-in may not send partially-archived content down to the client the first time the client connects. To correctly stream partially-archived content to these clients, the cache proxy plug-in should begin downloading content from the origin server when the client sends a PLAY request to the cache proxy server.
Clients connecting to a partially-archived file will start streaming from the beginning of the stream. Also, because this file is in the process of being written, it is not indexed, and thus is not seekable or stridable. To the client, the viewing experience would be similar to connecting to a broadcast publishing point. After archiving is complete, the file is indexed and becomes a normal media file that is seekable and stridable.
The Play While Archiving functionality is enabled by setting two server namespace values on the following nodes:
<node name="File Share Read Only" opcode="create" type="int32" value="0x1" />
<node name="Only File Read Share" opcode="create" type="int32" value="0x1" />
These values can be set at either the publishing point or server level. Both of these namespace values are optional and default to 0.
The File Share Read Only node is under the WMS NTFS ACL Authorization node, and the Only File Read Share node is under the WMS File Data Source node.
If the WMS NTFS ACL Authorization plug-in is enabled, then both of the values must be the same for a given level. For example, if the WMS NTFS ACL Authorization plug-in is enabled on the server level, then both the File Share Read Only and the Only File Read Share nodes must be set to the same value on the server level.
For more information on the server namespace, see Understanding the Namespace.
Note
Play While Archiving is available only on Windows Server 2003, Enterprise Edition with Service Pack 1; Windows Server 2003, Datacenter Edition with Service Pack 1; Windows Server 2008 Enterprise; and Windows Server 2008 Datacenter.