Abstract: A computer-implemented method for processing a video stream is provided. The method comprises receiving a video stream, selecting portions of the image data, and modifying the selected portions to generate modified portions of image data. Second data is generated for use in recovering at least some of the selected portions from the modified portions. The second data, unselected portions of the image data, and the modified portions of the image data are output. A system and non-transitory computer-readable storage medium according to this method are also provided. A computer-implemented method for data processing is provided. The method for data processing comprising receiving second data and modified portions of the image data, and processing at least some of the modified portions using the second data to recover selected portions of the image data. A system and non-transitory computer-readable storage medium according to the method for data processing are also provided.