Patent attributes
Techniques are presented for inserting markers into a video stream. For each frame of an encoded video stream, disclosed techniques may determine a structure of macroblocks from a code of the frame, and then, select macroblocks to be replaced from the determined structure of macroblocks. Inserting a marker into a frame may be carried out by replacing codes of the selected macro blocks with a code of a marker that identifies the frame. Marking frames of the video stream may facilitate finding correspondence between frames from the video stream before transmission over a channel and the video stream received from the channel, based on the inserted markers. Knowledge of frame correspondence may enable a video quality metric estimation based on a comparison between the found corresponding frames.