1. A method of automatically determining a subjective measure of quality of signals over a packet-switched network, comprising: transmitting input signals to a simulation model of the packet-switched network to obtain transmitted input signals, wherein said transmitting includes encoding the input signals to produce encoded signals, packetizing the encoded signals to produce packetized signals, and streaming the packetized signals to produce the transmitted input signals; altering the transmitted input signals using the model of the packet-switched network to obtain altered signals, the altered signals representing results of transmitting the transmitted input signals through the packet-switched network; modifying the altered signals to obtain output signals, wherein said modifying includes playing out the altered signals to produce packetized signals, depacketizing the packetized signals to produce encoded signals, and decoding the encoded signals to produce the output signals; measuring an objective quality of the output signals based on the input signals wherein said measuring relies upon a machine-executable algorithm that receives an original reference signal and compares said reference signal to at least one of said altered signals; and transforming the objective quality to the subjective measure of quality by mapping a value of said objective quality to a subjective quality score.