CRefTime Class

The CRefTime class is a helper class for managing reference times.

A reference time is a unit of time represented in 100-nanosecond units. This class shares the same data layout as the REFERENCE_TIME data type, but adds some methods and operators that provide comparison, conversion, and arithmetic functions. For more information about reference times, see Time and Clocks in DirectShow.

Note   There is a potential pitfall with using this class. If you apply the += operator with a CRefTime object as the left operand and a variable of type LONG as the right operand, the compiler will implicitly coerce the right operand into a CRefTime object. This coercion uses the CRefTime constructor that converts milliseconds into REFERENCE_TIME units; as a result, the right operand is multiplied by 10,000:

CRefTime rt;   // rt.m_time is 0.
LONG val = 20;
rt += val;    // Coerce val to CRefTime, rt.m_time is now 200,000.

However, the same thing does not happen using the + operator:

CRefTime rt;   // rt.m_time is 0.
LONG val = 20;
rt = rt + val; // CRefTime, rt.m_time is 20.

Requirements

Header: Declared in Reftime.h; include Streams.h.

Library: Use Strmbase.lib (retail builds) or Strmbasd.lib (debug builds).