A camera-recorder apparatus comprises an image capture device operable to capture a plurality of video images; a storage medium by which the video images are stored for later retrieval; a feature extraction unit operable to derive image property data from the image content of at least one of the video images substantially in real time at the capture of the video images, the image property data being associated with respective images or groups of images; and a data path by which the camera-recorder apparatus is operable to transfer the derived image property data to an external data processing apparatus.