Video coding

A receiving device for receiving a plurality of encoded multicast frames of a video from a transmitting device over a network, the receiving device including:

• a processor;
• and
• a memory including instructions configured to be executed by the processor, the instructions configuring the processor to:
• generate an error message indicating at least one erroneous multicast frame of said plurality of multicast frames that has not been both received and decoded at the receiving device and indicating a last known good multicast frame that has been both received and decoded at the receiving device;
• transmit said error message over a feedback channel to the transmitting device;
• receive a recovery multicast frame from the transmitting device over said network;
• wherein:
• said recovery multicast frame includes information pertaining to a previously decoded multicast frame and information pertaining to a current multicast frame to be decoded based on the previously decoded multicast frame,
• the receiving device is one receiving device of a plurality of receiving devices configured to receive the plurality of multicast video frames;
• and
• the previously decoded multicast frame is an earliest last known good frame, and the current multicast frame is a latest erroneous multicast frame derived from respective error messages generated by the plurality of receiving devices.

A method comprising:

• receiving a plurality of error messages over a respective plurality of feedback channels from a respective plurality of receiving devices, each error message including an indication of a respective current frame of a multicast video that has not been received or has been rejected as corrupted at the respective receiving device and an indication of a last known good frame of the multicast video that has been decoded by the respective receiving device;
• selecting an earliest last known good frame of the multicast video from the plurality of error messages;
• selecting a latest current frame of the multicast video from the plurality of error messages;
• encoding a recovery frame of the multicast video based on the earliest last known good frame and the latest current frame;
• and
• transmitting said recovery frame of the multicast video to the plurality of receiving devices.