A method performed by a transmitter for enabling validation of a video sequence by providing the video sequence with a data structure and a digital signature, wherein the video sequence comprises encoded image frames, and wherein the method comprises: - performing lossless compression of each encoded image frame of the video sequence to obtain a respective losslessly compressed, LC, encoded image frame; - among the obtained LC encoded image frames identifying one or more small LC encoded image frames (220LCb-1, 220LCb-2) each having a data size that is smaller than a predefined number of bytes; - generating a data structure comprising: - the identified one or more small LC encoded image frames (220LCb-1, 220LCb-2); and - individual hashes of either: all encoded image frames for which the obtained respective LC encoded image frame is not identified as a respective small LC encoded image frame (220LCb-1, 220LCb-2); or all other obtained respective LC encoded image frames not being identified as one or more small LC encoded image frames (220LCb-1, 220LCb-2), wherein the individual hashes are obtained by individually hashing each one of the all encoded image frames for which the obtained respective LC encoded image frame is not identified as a respective small LC encoded image frame (220LCb-1, 220LCb-2), or by individually hashing each one of the all other obtained respective LC encoded image frame not being identified as a small LC encoded image frame (220LCb-1, 220LCb-2), respectively; - generating a digital signature for the video sequence; and - providing the data structure and the digital signature to the video sequence, thereby enabling a receiver to validate the video sequence. - performing lossless compression of each encoded image frame of the video sequence to obtain a respective losslessly compressed, LC, encoded image frame; - among the obtained LC encoded image frames identifying one or more small LC encoded image frames (220LCb-1, 220LCb-2) each having a data size that is smaller than a predefined number of bytes; - generating a data structure comprising: - the identified one or more small LC encoded image frames (220LCb-1, 220LCb-2); and - individual hashes of either: all encoded image frames for which the obtained respective LC encoded image frame is not identified as a respective small LC encoded image frame (220LCb-1, 220LCb-2); or all other obtained respective LC encoded image frames not being identified as one or more small LC encoded image frames (220LCb-1, 220LCb-2), wherein the individual hashes are obtained by individually hashing each one of the all encoded image frames for which the obtained respective LC encoded image frame is not identified as a respective small LC encoded image frame (220LCb-1, 220LCb-2), or by individually hashing each one of the all other obtained respective LC encoded image frame not being identified as a small LC encoded image frame (220LCb-1, 220LCb-2), respectively; - the identified one or more small LC encoded image frames (220LCb-1, 220LCb-2); and - individual hashes of either: all encoded image frames for which the obtained respective LC encoded image frame is not identified as a respective small LC encoded image frame (220LCb-1, 220LCb-2); or all other obtained respective LC encoded image frames not being identified as one or more small LC encoded image frames (220LCb-1, 220LCb-2), wherein the individual hashes are obtained by individually hashing each one of the all encoded image frames for which the obtained respective LC encoded image frame is not identified as a respective small LC encoded image frame (220LCb-1, 220LCb-2), or by individually hashing each one of the all other obtained respective LC encoded image frame not being identified as a small LC encoded image frame (220LCb-1, 220LCb-2), respectively; all encoded image frames for which the obtained respective LC encoded image frame is not identified as a respective small LC encoded image frame (220LCb-1, 220LCb-2); or all other obtained respective LC encoded image frames not being identified as one or more small LC encoded image frames (220LCb-1, 220LCb-2), - generating a digital signature for the video sequence; and - providing the data structure and the digital signature to the video sequence, thereby enabling a receiver to validate the video sequence.