A method for reconstructing and rendering audio objects based on a data stream, comprising: receiving a data stream (140, 240, 340, 540) comprising: a downmix comprising M downmix signals (124, 126, 224, 226, 324, 326) suitable for playback on channels of a speaker configuration with M channels, wherein the M downmix signals are combinations of N audio objects (120, 121, 220, 421a), wherein N>1 and M≤N, time-variable side information (128, 228, 528) including parameters which allow reconstruction of the N audio objects from M downmix signals, and a plurality of metadata instances (122, 222, 325, 423, 522, 810) associated with the N audio objects, the plurality of metadata instances specifying respective desired rendering settings for rendering the N audio objects, and, for each metadata instance, transition data including a start time and a duration of an interpolation from a current rendering setting to the desired rendering setting specified by the metadata instance; reconstructing the N audio objects based on the downmix and the side information; and rendering the N audio objects to output channels of a predefined channel configuration by: performing rendering according to a current rendering setting, beginning, at a start time defined by the transition data for a metadata instance, an interpolation from the current rendering setting to a desired rendering setting specified by the metadata instance, and completing the interpolation to the desired rendering setting after a duration defined by the transition data for the metadata instance. receiving a data stream (140, 240, 340, 540) comprising: a downmix comprising M downmix signals (124, 126, 224, 226, 324, 326) suitable for playback on channels of a speaker configuration with M channels, wherein the M downmix signals are combinations of N audio objects (120, 121, 220, 421a), wherein N>1 and M≤N, time-variable side information (128, 228, 528) including parameters which allow reconstruction of the N audio objects from M downmix signals, and a plurality of metadata instances (122, 222, 325, 423, 522, 810) associated with the N audio objects, the plurality of metadata instances specifying respective desired rendering settings for rendering the N audio objects, and, for each metadata instance, transition data including a start time and a duration of an interpolation from a current rendering setting to the desired rendering setting specified by the metadata instance; a downmix comprising M downmix signals (124, 126, 224, 226, 324, 326) suitable for playback on channels of a speaker configuration with M channels, wherein the M downmix signals are combinations of N audio objects (120, 121, 220, 421a), wherein N>1 and M≤N, time-variable side information (128, 228, 528) including parameters which allow reconstruction of the N audio objects from M downmix signals, and a plurality of metadata instances (122, 222, 325, 423, 522, 810) associated with the N audio objects, the plurality of metadata instances specifying respective desired rendering settings for rendering the N audio objects, and, for each metadata instance, transition data including a start time and a duration of an interpolation from a current rendering setting to the desired rendering setting specified by the metadata instance; reconstructing the N audio objects based on the downmix and the side information; and rendering the N audio objects to output channels of a predefined channel configuration by: performing rendering according to a current rendering setting, beginning, at a start time defined by the transition data for a metadata instance, an interpolation from the current rendering setting to a desired rendering setting specified by the metadata instance, and completing the interpolation to the desired rendering setting after a duration defined by the transition data for the metadata instance. performing rendering according to a current rendering setting, beginning, at a start time defined by the transition data for a metadata instance, an interpolation from the current rendering setting to a desired rendering setting specified by the metadata instance, and completing the interpolation to the desired rendering setting after a duration defined by the transition data for the metadata instance.