A method for providing privacy masks on a video stream, comprising: selecting at least one image region in a video to which region a privacy mask should be applied, characterized in that : for an image frame in the video that contains the at least one image region: setting a flag for the image frame to indicate an I-frame as a non-displayed image frame ; and inserting a forward-predicted image frame referencing the non-displayed image frame , wherein coding units representing the at least one image region are processed differently from coding units representing areas outside the at least one image region, such that coding units representing the at least one image region are obfuscated to collectively form the privacy mask and coding units representing areas outside the at least one image region are set as skip blocks referring to the non-displayed image frame ; and outputting a video stream including both the non-displayed image frame and the forward-predicted image frame . selecting at least one image region in a video to which region a privacy mask should be applied, characterized in that : for an image frame in the video that contains the at least one image region: setting a flag for the image frame to indicate an I-frame as a non-displayed image frame ; and inserting a forward-predicted image frame referencing the non-displayed image frame , wherein coding units representing the at least one image region are processed differently from coding units representing areas outside the at least one image region, such that coding units representing the at least one image region are obfuscated to collectively form the privacy mask and coding units representing areas outside the at least one image region are set as skip blocks referring to the non-displayed image frame ; and outputting a video stream including both the non-displayed image frame and the forward-predicted image frame . for an image frame in the video that contains the at least one image region: setting a flag for the image frame to indicate an I-frame as a non-displayed image frame ; and inserting a forward-predicted image frame referencing the non-displayed image frame , wherein coding units representing the at least one image region are processed differently from coding units representing areas outside the at least one image region, such that coding units representing the at least one image region are obfuscated to collectively form the privacy mask and coding units representing areas outside the at least one image region are set as skip blocks referring to the non-displayed image frame ; and setting a flag for the image frame to indicate an I-frame as a non-displayed image frame ; and inserting a forward-predicted image frame referencing the non-displayed image frame , wherein coding units representing the at least one image region are processed differently from coding units representing areas outside the at least one image region, such that coding units representing the at least one image region are obfuscated to collectively form the privacy mask and coding units representing areas outside the at least one image region are set as skip blocks referring to the non-displayed image frame ; and outputting a video stream including both the non-displayed image frame and the forward-predicted image frame . <EOS>