System and method for analyzing and transmitting video over a switched network

A method for analyzing an encoded video sequence to be transmitted over a network from a source location to a destination location, said method comprising:

• providing a model of a decoder buffer, said decoder buffer model including parameters indicating the size of a decoder buffer provided at the destination location and a rate at which video frames are removed from the decoder buffer;
• pre-filling said decoder buffer model at a predetermined sustained cell rate SCR, said decoder buffer model being pre-filled with a maximum number N of video frames of said video sequence that will fit in the decoder buffer model;
• calculating a transmission rate R for the next video frame to be transmitted after the pre-filling of said decoder buffer model, said transmission rate R being calculated based on the size of the next video frame and the maximum number N of video frames that can be pre-filled into said decoder buffer model;
• determining if said calculated transmission rate R is less than the sustained cell rate SCR;
• setting said transmission rate R to be equal to the sustained cell rate SCR if it is determined that the rate R is less than the sustained cell rate SCR;
• determining if the transmission R will cause an overflow of said decoder buffer model;
• recalculating the transmission rate R if it is determined that overflow of said decoder buffer model will occur, said transmission rate R being recalculated based on the maximum number N of video frames that can be pre-filled into said decoder buffer model and the difference between the size of the decoder buffer model and the current occupancy of the decoder buffer model;
• and
• determining a new transmission rate for the next frame period after each video frame is removed from said decoder buffer model, said new transmission rate being calculated in accordance with the foregoing steps for calculating the transmission rate R and with the maximum number N being replaced with the number of current frames in the decoder buffer model.

A method for transmitting an encoded video sequence over a switched network from a source location to a destination location, said method comprising:

• providing a model of a decoder buffer, said decoder buffer model including parameters indicating the size of a decoder buffer provided at the destination location and a rate at which video frames are removed from the decoder buffer;
• establishing a connection over the network in accordance with a predetermined set of traffic control parameters, said predetermined set of traffic control parameters including a sustained cell rate SCR and a peak cell rate PCR;
• pre-filling the decoder buffer at the destination location by transmitting video frames of said video sequence over the network in transmission cells at the sustained cell rate SCR;
• determining when said decoder buffer is pre-filled with a maximum number N of video frames that will fit in the decoder buffer based on the parameters of the decoder buffer model;
• transmitting, after pre-filling the decoder buffer, the next transmission cell at the peak cell rate PCR if a token is available and the decoder buffer is not full;
• and
• transmitting, after pre-filling the decoder buffer, the next transmission cell at the sustained cell rate SCR if no tokens are available and the decoder buffer is not full.