The present invention provides an information-processing apparatus including reproduction means for synchronously reproducing content data common to an other information-processing apparatus, user information input means for inputting first user condition information including a voice and image of a user, user information receiver means for receiving second user condition information including a voice and image of an other user from the other information-processing apparatus, synthesis means for synthesizing a voice and image of the content data synchronously reproduced by the reproduction means with the voice and image of the second user condition information received by the user-information receiver means; information analysis means for analyzing at least either the first user condition information input by the user-information input means or the second user condition information received by the user-information receiver means, and parameter-setting means for setting a control parameter used for controlling a process, which is carried out by the synthesis means to synthesize voices and images, on the basis of an analysis result produced by the information analysis means.