-#define PA_MSEC_PER_SEC 1000
-#define PA_USEC_PER_SEC 1000000
-#define PA_NSEC_PER_SEC 1000000000
+/** The number of milliseconds in a second */
+#define PA_MSEC_PER_SEC ((pa_usec_t) 1000ULL)
+
+/** The number of microseconds in a second */
+#define PA_USEC_PER_SEC ((pa_usec_t) 1000000ULL)
+
+/** The number of nanoseconds in a second */
+#define PA_NSEC_PER_SEC ((unsigned long long) 1000000000ULL)
+
+/** The number of microseconds in a millisecond */
+#define PA_USEC_PER_MSEC ((pa_usec_t) 1000ULL)
+
+/** The number of nanoseconds in a millisecond */
+#define PA_NSEC_PER_MSEC ((unsigned long long) 1000000ULL)
+
+/** The number of nanoseconds in a microsecond */
+#define PA_NSEC_PER_USEC ((unsigned long long) 1000ULL)
+
+/** Invalid time in usec. \since 0.9.15 */
+#define PA_USEC_INVALID ((pa_usec_t) -1)
+
+/** Biggest time in usec. \since 0.9.18 */
+#define PA_USEC_MAX ((pa_usec_t) -2)