KsCacheMedium function (ks.h)

Article
02/22/2024

The KsCacheMedium function improves graph building performance of pins that use Mediums to define connectivity.

Syntax

KSDDKAPI NTSTATUS KsCacheMedium(
  [in] PUNICODE_STRING SymbolicLink,
  [in] PKSPIN_MEDIUM   Medium,
  [in] ULONG           PinDirection
);

Parameters

[in] SymbolicLink

The symbolic link used to open the device interface.

[in] Medium

Points to the medium to cache.

[in] PinDirection

Contains the direction of the Pin. 1 is output, 0 is input.

Return value

KsCacheMedium returns STATUS_SUCCESS if the caching operation is successful, failure if it is not.

Remarks

KsCacheMedium improves graph building performance by creating a registry key at:

\System\CurrentControlSet\Control\MediumCache\GUID\DWORD\DWORD

This enables fast lookup of connected filters in TvTuner and other complex graphs. Note that the GUID identifies the Medium of the connection, and that the DWORDs denote the device instance. The value name is the SymbolicLink for the driver, and ActualValue is the pin direction.turning.

Requirements

Requirement	Value
Target Platform	Universal
Header	ks.h (include Ks.h)
Library	Ks.lib

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