A method of editing a signed video bitstream obtained by prediction coding of a video sequence, the signed video bitstream including data units and associated signature units, wherein each data unit represents at most one macroblock in a video frame of the prediction-coded video sequence, and wherein each signature unit includes a digital signature ( s ( H 1), s ( H 2)) of a bitstring ( H 1, H 2) derived from a plurality of fingerprints ( h 1, h 2,...) of exactly one associated data unit each, the method comprising: receiving a request to substitute a region of at least one video frame; determining a first set of macroblocks, in which said region is contained, and a second set of macroblocks referring directly or indirectly to macroblocks in the first set; adding an archive object to the signed video bitstream, the archive object including fingerprints of a first and a second set of data units, which respectively represent the determined first and second set of macroblocks, wherein the archive object includes positions of the first and second sets of macroblocks; editing the first set of data units in accordance with the request to substitute the region of the at least one video frame, wherein the editing of the first set of data units comprises: decoding (618.1) the data unit into a reconstructed macroblock, providing (618.2) an edited macroblock by performing the requested substitution on the reconstructed macroblock, and providing (618.3) an edited data unit by encoding the edited macroblock; and re-encoding the second set of data units. the signed video bitstream including data units and associated signature units, wherein each data unit represents at most one macroblock in a video frame of the prediction-coded video sequence, and wherein each signature unit includes a digital signature ( s ( H 1), s ( H 2)) of a bitstring ( H 1, H 2) derived from a plurality of fingerprints ( h 1, h 2,...) of exactly one associated data unit each, the method comprising: receiving a request to substitute a region of at least one video frame; determining a first set of macroblocks, in which said region is contained, and a second set of macroblocks referring directly or indirectly to macroblocks in the first set; adding an archive object to the signed video bitstream, the archive object including fingerprints of a first and a second set of data units, which respectively represent the determined first and second set of macroblocks, wherein the archive object includes positions of the first and second sets of macroblocks; editing the first set of data units in accordance with the request to substitute the region of the at least one video frame, wherein the editing of the first set of data units comprises: decoding (618.1) the data unit into a reconstructed macroblock, providing (618.2) an edited macroblock by performing the requested substitution on the reconstructed macroblock, and providing (618.3) an edited data unit by encoding the edited macroblock; and re-encoding the second set of data units. receiving a request to substitute a region of at least one video frame; determining a first set of macroblocks, in which said region is contained, and a second set of macroblocks referring directly or indirectly to macroblocks in the first set; adding an archive object to the signed video bitstream, the archive object including fingerprints of a first and a second set of data units, which respectively represent the determined first and second set of macroblocks, wherein the archive object includes positions of the first and second sets of macroblocks; editing the first set of data units in accordance with the request to substitute the region of the at least one video frame, wherein the editing of the first set of data units comprises: decoding (618.1) the data unit into a reconstructed macroblock, providing (618.2) an edited macroblock by performing the requested substitution on the reconstructed macroblock, and providing (618.3) an edited data unit by encoding the edited macroblock; and decoding (618.1) the data unit into a reconstructed macroblock, providing (618.2) an edited macroblock by performing the requested substitution on the reconstructed macroblock, and providing (618.3) an edited data unit by encoding the edited macroblock; and re-encoding the second set of data units.