The present invention relates to a reception device and a method for the processing of multimedia data flows in said device comprising an interface to a first network and an interface to a second network, said method comprising the following steps: receive, from the first network, a first flow comprising multimedia data through a first transport protocol fitted with a first data synchronization system; receive, from the second network, a second flow comprising multimedia data through a second transport protocol fitted with a second data synchronization system, said second synchronization system being based on timing references different from those of the first data synchronization system; characterized in that said first and second flows transport the same synchronization information in the payload field of the first and of the second transport protocol, said synchronization information comprising data indicating the moment from which said multimedia data must be rendered; synchronize said first and second flows by using said synchronization information; and perform a step for rendering said first and second multimedia flows.