Abstract: A mechanism is disclosed to adapt in real-time the encoding bitrate of a video source in an adaptive video streaming system with the aim of avoiding playback interruptions and to guarantee the best possible video quality. The mechanism is made of a feedback loop in which a controller computes the encoding bitrate that the sender (the video server) transmits to a receiver (client) employing a packet switching network such as the Internet. The mechanism can be used in video streaming systems employing scalable encoding (f.i. H.264 SVC, VP8, VP9) or multi bit-rate encoding (stream-switching). The automatic control that computes the video encoding bitrate can be executed either at the server or at the client.