A method comprising: receiving , by a computing system, query fingerprints of frames of a media stream being received by a client , wherein the query fingerprints are generated by the client at a frame rate, the frame rate defining a quantity of frames per unit time for which query fingerprints are generated; determining by the computing system that the media stream being received by the client is a known media stream, wherein the determining is based on a comparison by the computing system of (i) the query fingerprints generated at the frame rate with (ii) reference fingerprints representing the known media stream; responsive to the determining, causing by the computing system the client to increase the frame rate at which the client generates the query fingerprints being received by the computing system; using by the computing system the query fingerprints generated at the increased frame rate as a basis to establish a time mapping between (i) true time defined along a timeline within the known media stream and (ii) client time defined according to a clock of the client by detecting at least one match between the query fingerprints generated by the client at the increased frame rate and reference fingerprints of the known media stream, and correlating a true-time timestamp of the at least one match with a client-time timestamp of the at least one match; using by the computing system the established time mapping as a basis to map a predefined true-time point at which a content revision should be performed in the known media stream to a corresponding client-time point at which the client should perform the content revision in the media stream being received by the client ; and causing the client to perform, at the determined client-time point, the content revision. receiving , by a computing system, query fingerprints of frames of a media stream being received by a client , wherein the query fingerprints are generated by the client at a frame rate, the frame rate defining a quantity of frames per unit time for which query fingerprints are generated; determining by the computing system that the media stream being received by the client is a known media stream, wherein the determining is based on a comparison by the computing system of (i) the query fingerprints generated at the frame rate with (ii) reference fingerprints representing the known media stream; responsive to the determining, causing by the computing system the client to increase the frame rate at which the client generates the query fingerprints being received by the computing system; using by the computing system the query fingerprints generated at the increased frame rate as a basis to establish a time mapping between (i) true time defined along a timeline within the known media stream and (ii) client time defined according to a clock of the client by detecting at least one match between the query fingerprints generated by the client at the increased frame rate and reference fingerprints of the known media stream, and correlating a true-time timestamp of the at least one match with a client-time timestamp of the at least one match; using by the computing system the established time mapping as a basis to map a predefined true-time point at which a content revision should be performed in the known media stream to a corresponding client-time point at which the client should perform the content revision in the media stream being received by the client ; and causing the client to perform, at the determined client-time point, the content revision. <EOS>