A media client ascertains a plurality of matching points between (i) query fingerprints representing a media stream being received by the client and (ii) reference fingerprints, each identified matching point defining a respective match between a query fingerprint that is timestamped with client time defined according to a clock of the client and a reference fingerprint that is timestamped with true time defined according to a timeline within a known media stream. Further, the client performs linear regression based on the timestamps of the ascertained plurality of matching points, to establish a mapping between true time and client time. The client then uses the established mapping as a basis to determine a client-time point at which the client should perform an action with respect to media stream being received by the client. And the client performs the action at the determined client-time point.