Conditional concealment of lost video data

A computer program product for processing a video signal comprising a plurality of frames, comprising code embodied on a computer-readable storage medium and configured so as when executed on a receiving terminal to perform operations comprising:

• processing the video signal for output to a screen, storage device or further terminal;
• and
• conditionally applying a concealment algorithm over an area of said video signal having lost data;
• wherein the conditional application of the concealment algorithm comprises determining an estimate of concealment quality selectively directed towards a region of interest within said area, and, based on said estimate, determining whether or not to apply the concealment algorithm.

A computer program product comprising code embodied on a computer-readable storage medium and configured so as when executed on a terminal of a first user to perform operations comprising:

• establishing a live video call with a terminal of a second user over a packet-based network, and as part of the call receiving, in encoded form, a live video stream comprising a plurality of frames representing the second user;
• decoding the received frames of the video stream and outputting the video stream to a screen;
• conditionally applying a concealment algorithm to a target frame of said video stream having lost data, the concealment algorithm projecting a replacement for the lost data from a previous received, decoded frame;
• wherein the conditional application of the concealment algorithm comprises determining within the frame a region of interest comprising an image of at least part of the second user's face, determining an estimate of concealment quality selectively directed towards said region of interest, and, based on said estimate, making a determination for the whole target frame as to whether or not to apply the concealment algorithm, so as when applied to conceal lost data from the region of interest and lost data from a region of the target frame outside the region of interest;
• and
• wherein when the concealment algorithm is not applied, instead a preceding frame is frozen for a duration corresponding to the target frame.