A new real time loss tolerant video streaming authentication scheme is presented. The bandwidth overhead is negligible, and authentication information are transmitted from the sender to all the receivers by means of a watermarking technique. Real time constraints are achieved by using a features computation algorithm, the sender embeds in each block of pictures the features computed over the current block, and a message authentication code that authenticates them. The receiver computes the features over the received block and compares it with that ones authenticated and extracted from the current block.