A method, apparatus, and medium for rendering an audio program to a number of loudspeaker feed signals are provided. The audio program may include one or more audio objects, and metadata associated with each of the one or more audio objects. The metadata may include position information indicating a time-varying position of the audio object and a parameter indicating whether the audio object should be reproduced at the time-varying position, or at one of a plurality of fixed positions. In response to the position and the parameter, a position at which to reproduce each audio object may be determined. The determined position may be one of the plurality of fixed positions that is nearest to the time-varying position indicated by the position information. Each audio object may be reproduced at the determined position by rendering the audio object into one or more of the loudspeaker feed signals.