Multimedia Class Scheduler Service (MMCSS) is a Windows service that boosts the CPU as well as I/O priority of a thread. It allows an application to get prioritized access to CPU for time-sensitive processing (such as multimedia applications) as well as prioritized disc access to ensure that the process is not starved off data to process. The MMCSS service monitors the CPU load and dynamically adjusts priority so that the application can use as much of CPU time as possible without denying CPU to lower priority application.[1] MMCSS uses heuristics to determine the relative priority required for the task the thread is performing and dynmaically adjusts priority based on that.[1] A thread must invoke MMCSS explicitly to use its services by calling the AvSetMmMaxThreadCharacteristics()
[2] or AvSetMmThreadCharacteristics()
[3] APIs.
MMCSS is used by the multimedia applications in Windows Vista, including Windows Media Player and Windows Media Center to provide glitch-free audio playback.
See also
References
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