You can modify how Windows Media Player uses the Advanced Fast Start feature and buffers content by using URL modifiers. The following table describes the URL modifiers that can be used to minimize startup latency for a unicast:
|Modifer||Description||Value range||Sample value|
|WMBufferTime||Sets the size of the client buffer. The value is
added to the preroll buffer size to determine the total amount of
data that is buffered on the client.
Use this modifier to set the minimum buffer size to reduce channel-change latency when switching between multicast streams. If Advanced Fast Start is enabled for unicast streaming, the buffer size typically does not increase latency. For more information, see Controlling multicast client buffer behavior with URL modifiers.
|0 or more milliseconds||1000|
|WMStartupProfile||Disables Advanced Fast Start. By default, Advanced Fast Start is used if it is enabled on the server and supported by the Player.||0 to disable||0|
|WMStartUpBufferSize||This value is multiplied by the content buffer size to determine the minimum buffer size at the end of Advanced Fast Start acceleration period.||1.0 to 9.9 times||2.5 times|
|WMStartupProfileJitter||This value is added to the network buffer size calculated by Advanced Fast Start. The network buffer helps to smooth inconsistent data flow caused by network fluctuations.||0 or more milliseconds||200|
|WMStartupProfileCheck||Disables the check that verifies the buffer size at the end of the Advanced Fast Start acceleration period. If network conditions are good, you can disable this check to improve latency.||0||0|
|WMAccelDurationTCP||Sets the Advanced Fast Start acceleration period duration when content is streamed using TCP. The default with Advanced Fast Start is 18000. In players that do not support Advanced Fast Start, the default is 10000.||0 or more milliseconds||20000|
|WMAccelDurationUDP||Sets the Advanced Fast Start acceleration period duration when content is streamed using UDP. The default with Advanced Fast Start is 10000. In players that do not support Advanced Fast Start, the default is 8000.||0 or more milliseconds||10000|