Fast Streaming

If you’ve clicked an audio or video link on the Internet, then you’ve probably experienced the buffering that occurs while your Player collects enough data to render the stream. You’ve probably also experienced some rebuffering or choppy playback when you clicked your Player’s fast forward or rewind controls. This buffering and rebuffering occurs because the Player has used up the data in its buffer and is waiting for the buffer to be refilled with additional content from the server. This kind of playback experience can be extremely frustrating.

Windows Media Services now addresses these playback interruptions through a set of features called Fast Streaming. The Fast Streaming feature, when combined with Windows Media Player 9 Series, virtually eliminates annoying buffering delays and playback interruptions by taking advantage of networking resources, such as available bandwidth and network signaling to deliver content to the Player quickly. Furthermore, Fast Streaming provides redundancy and automatic restoration of dropped connections to ensure an uninterrupted viewing experience. Fast Streaming is possible because of the following four components:

Fast Start

When Windows Media Services receives a stream request, it takes advantage of available bandwidth to fill the Windows Media Player buffer at a bit rate that exceeds that of the requested stream. This enables the Player to start rendering the stream more quickly. After the initial buffer requirement is fulfilled, the server streams the content at the requested bit rate. Buffering the content in this way enables end users to fast forward and rewind content without additional delay and rebuffering. Fast Start is supported in Windows Media Player for Windows XP and Windows Media Player 9 Series.

Fast Cache

This feature enables Windows Media Player to cache streamed content thus making it available later without having to stream it again. This saves network bandwidth on subsequent requests. Fast Cache also enhances the Player’s ability to play back the content faster or slower than real time and makes the Player resistant to playback errors due to lost packets or other network issues. Fast Cache is not supported when streaming with UDP.

Fast Recovery

Fast Recovery makes use of forward error correction (FEC) to stream content to a Player that has unreliable network connections. In an environment that is subject to latency problems, such as satellite wireless networks, FEC enables the server to send data packets containing redundant data to Players. The Player then uses this redundant data to correct missing or corrupted data packets during playback. With the help of FEC, the Player can usually recover lost or damaged data packets without having to request that the server resend the data. FEC and Fast Recovery can only be used with clients such as Windows Media Player 9 Series that connect to your server using the RTSP protocol in conjunction with UDP (RTSPU).

Fast Reconnect

Fast Reconnect minimizes the impact to Windows Media Player during a temporary network outage by enabling the Player to reconnect to the server automatically and restart streaming. If the Player was connected to an on-demand publishing point, playback starts at the point at which the connection was lost. If the content includes video, the Player estimates the approximate video frame at which the connection was lost. If the content is indexed, this estimate is more accurate. For a connection to a broadcast publishing point, the Player reconnects to the broadcast in progress. Depending on the content and whether Fast Cache is enabled, there may be a gap in the broadcast. Fast Reconnect is available to any client that connects using the default MMS, HTTP, or RTSP protocols.