Patent ID: 8284231

Claim:
A method for selecting input video signals in a video conference, comprising the steps of: receiving, from a user, values of a set of parameters defining quantitative properties of the selecting; continuously receiving at least one input video signal; receiving, for each input video signal, an associated input audio signal and performing a recurring voice activity detection, VAD, which assigns a binary value to each input video signal, wherein a value 1 means that voice activity is detected and a value 0 means that it is not; determining a set of constraints including at least a steadiness constraint, an anti-flickering constraint, a swapping-time constraint and a preference constraint; selecting for transmission those input video signals to which a value 1 has been assigned and unselecting those input video signals to which a value 0 has been assigned, unless doing so would violate at least one constraint in the set of constraints; wherein the steadiness constraint stipulates, firstly, that any previously selected input signal shall remain selected, and, secondly, that any previously unselected signal shall remain unselected during at least C consecutive VADs; wherein the anti-flickering constraint stipulates that between two consecutive VADs the total number of signals being changed either from previously selected to unselected or from previously unselected to selected shall not exceed N; wherein the swapping-time constraint stipulates that no previously selected input video signal shall be unselected unless a value 0 has been assigned to the signal at S consecutive VADs; and wherein the preference constraint stipulates that any input video signals shall remain selected if they have been associated with the M greatest values of an accumulated voice activity, which is based on the most recent VAD outputs, where C, N, S and M are numbers in accordance with the set of parameters defining quantitative properties of the selecting; and continuously transmitting the input video signals selected for transmission.