1. An apparatus (100; 200) for upmixing a downmix audio signal (110; 210) describing one or more downmix audio channels into an upmixed audio signal (120; 214) describing a plurality of upmixed audio channels, the apparatus comprising: an upmixer (130; 230) configured to apply temporally variable upmix parameters (150; 262; Hij) to upmix the downmix audio signal (110; 210) in order to obtain the upmixed audio signal (120; 214); and a parameter interpolator (140; 260), wherein the parameter interpolator is configured to obtain one or more temporally interpolated upmix parameters (150; 262) to be used by the upmixer (130; 230) on the basis of an information describing a first complex-valued upmix parameter (142) and a subsequent second complex-valued upmix parameter (144), wherein the parameter interpolator (140; 260) is configured to separately interpolate (a) between a magnitude value (254) of the first complex-valued upmix parameter (142) and a magnitude value (254) of the second complex-valued upmix parameter (144), and (b) between a phase value (256) of the first complex- valued upmix parameter (142) and a phase value (256) of the second complex-valued upmix parameter (144), to obtain the one or more temporally interpolated complex-valued upmix parameters (150; 262); wherein the parameter interpolator (140; 260) is configured to determine a direction of the interpolation between the phase values (256) of subsequent complex-valued upmix parameters such that an angle-range passed in the interpolation between a phase value of the first complex-valued upmix parameter (142) and a phase value of the second complex-valued upmix parameter (144) is smaller than, or equal to, 180°.

2. An apparatus (100; 200) for upmixing a downmix audio signal (110; 210) describing one or more downmix audio channels into an upmixed audio signal (120; 214) describing a plurality of upmixed audio channels, the apparatus comprising: an upmixer (130; 230) configured to apply temporally variable upmix parameters (150; 262; Hij) to upmix the downmix audio signal (110; 210) in order to obtain the upmixed audio signal (120; 214); and a parameter interpolator (140; 260), wherein the parameter interpolator is configured to obtain one or more temporally interpolated upmix parameters (150; 262) to be used by the upmixer (130; 230) on the basis of an information describing a first complex-valued upmix parameter (142) and a subsequent second complex-valued upmix parameter (144), wherein the parameter interpolator (140; 260) is configured to separately interpolate (a) between a magnitude value (254) of the first complex-valued upmix parameter (142) and a magnitude value (254) of the second complex-valued upmix parameter (144), and (b) between a phase value (256) of the first complex- valued upmix parameter (142) and a phase value (256) of the second complex-valued upmix parameter (144), to obtain the one or more temporally interpolated complex-valued upmix parameters (150; 262); wherein the parameter interpolator (140; 260) is configured to combine the separately interpolated magnitude values (274) and phase values (276) by applying a complex-valued rotation to the interpolated magnitude values (274), wherein an angle of the complex-valued rotation is determined by the interpolated phase values (276).

3. A method for upmixing a downmix audio signal (110; 210) describing one or more downmix audio channels into an upmixed audio signal (120; 214) describing a plurality of upmixed audio channels, the method comprising: applying temporally variable upmix parameters (150; 262; Hij) to upmix the downmix audio signal (110; 210) in order to obtain the upmixed audio signal (120; 214); and obtaining one or more temporally interpolated upmix parameters (150; 262) to be used by the upmixer (130; 230) on the basis of an information describing a first complex-valued upmix parameter (142) and a subsequent second complex-valued upmix parameter (144), wherein the method comprises separately interpolating (a) between a magnitude value (254) of the first complex-valued upmix parameter (142) and a magnitude value (254) of the second complex-valued upmix parameter (144), and (b) between a phase value (256) of the first complex- valued upmix parameter (142) and a phase value (256) of the second complex-valued upmix parameter (144), to obtain the one or more temporally interpolated complex-valued upmix parameters (150; 262); wherein the method comprises determining a direction of the interpolation between the phase values (256) of subsequent complex-valued upmix parameters such that an angle-range passed in the interpolation between a phase value of the first complex-valued upmix parameter (142) and a phase value of the second complex-valued upmix parameter (144) is smaller than, or equal to, 180°.

4. A method for upmixing a downmix audio signal (110; 210) describing one or more downmix audio channels into an upmixed audio signal (120; 214) describing a plurality of upmixed audio channels, the method comprising: applying temporally variable upmix parameters (150; 262; Hij) to upmix the downmix audio signal (110; 210) in order to obtain the upmixed audio signal (120; 214); and obtaining one or more temporally interpolated upmix parameters (150; 262) to be used by the upmixer (130; 230) on the basis of an information describing a first complex-valued upmix parameter (142) and a subsequent second complex-valued upmix parameter (144), wherein the method comprises separately interpolating (a) between a magnitude value (254) of the first complex- valued upmix parameter (142) and a magnitude value (254) of the second complex-valued upmix parameter (144), and (b) between a phase value (256) of the first complex- valued upmix parameter (142) and a phase value (256) of the second complex-valued upmix parameter (144), to obtain the one or more temporally interpolated complex-valued upmix parameters (150; 262); wherein the method comprises obtaining the separately interpolated magnitude values (274) and phase values (276) by applying a complex-valued rotation to the interpolated magnitude values (274), wherein an angle of the complex-valued rotation is determined by the interpolated phase values (276).

5. A parameter determinator (140; 260) for determining temporally variable upmix parameters for upmixing a downmix audio signal (110; 210) describing one or more downmix audio channels into an upmixed audio signal (120; 214) describing a plurality of upmixed audio channels, wherein the parameter determinator comprises a parameter interpolator, wherein the parameter interpolator is configured to obtain one or more temporally interpolated upmix parameters (150; 262) to be used by an upmixer (130; 230) on the basis of an information describing a first complex-valued upmix parameter (142) and a subsequent second complex-valued upmix parameter (144), wherein the parameter interpolator (140; 260) is configured to separately interpolate (a) between a magnitude value (254) of the first complex-valued upmix parameter (142) and a magnitude value (254) of the second complex-valued upmix parameter (144), and (b) between a phase value (256) of the first complex- valued upmix parameter (142) and a phase value (256) of the second complex-valued upmix parameter (144), to obtain the one or more temporally interpolated complex-valued upmix parameters (150; 262); wherein the parameter interpolator (140; 260) is configured to determine a direction of the interpolation between the phase values (256) of subsequent complex-valued upmix parameters such that an angle-range passed in the interpolation between a phase value of the first complex-valued upmix parameter (142) and a phase value of the second complex-valued upmix parameter (144) is smaller than, or equal to, 180°.

6. A parameter determinator (140; 260) for determining temporally variable upmix parameters for upmixing a downmix audio signal (110; 210) describing one or more downmix audio channels into an upmixed audio signal (120; 214) describing a plurality of upmixed audio channels, wherein the parameter determinator comprises a parameter interpolator, wherein the parameter interpolator is configured to obtain one or more temporally interpolated upmix parameters (150; 262) to be used by an upmixer (130; 230) on the basis of an information describing a first complex-valued upmix parameter (142) and a subsequent second complex-valued upmix parameter (144), wherein the parameter interpolator (140; 260) is configured to separately interpolate (a) between a magnitude value (254) of the first complex-valued upmix parameter (142) and a magnitude value (254) of the second complex-valued upmix parameter (144), and (b) between a phase value (256) of the first complex- valued upmix parameter (142) and a phase value (256) of the second complex-valued upmix parameter (144), to obtain the one or more temporally interpolated complex-valued upmix parameters (150; 262); wherein the parameter interpolator (140; 260) is configured to combine the separately interpolated magnitude values (274) and phase values (276) by applying a complex-valued rotation to the interpolated magnitude values (274), wherein an angle of the complex-valued rotation is determined by the interpolated phase values (276). , Description:Attached herewith

Claims:We Claim

1. An apparatus (100; 200) for upmixing a downmix audio signal (110; 210) describing one or more downmix audio channels into an upmixed audio signal (120; 214) describing a plurality of upmixed audio channels, the apparatus comprising:

an upmixer (130; 230) configured to apply temporally variable upmix parameters (150; 262; Hij) to upmix the downmix audio signal (110; 210) in order to obtain the upmixed audio signal (120; 214); and

a parameter interpolator (140; 260), wherein the parameter interpolator is configured to obtain one or more temporally interpolated upmix parameters (150; 262) to be used by the upmixer (130; 230) on the basis of an information describing a first complex-valued upmix parameter (142) and a subsequent second complex-valued upmix parameter (144),

wherein the parameter interpolator (140; 260) is configured to separately interpolate

(a) between a magnitude value (254) of the first complex-valued upmix parameter (142) and a magnitude value (254) of the second complex-valued upmix parameter (144), and
(b) between a phase value (256) of the first complex- valued upmix parameter (142) and a phase value (256) of the second complex-valued upmix parameter (144),

to obtain the one or more temporally interpolated complex-valued upmix parameters (150; 262);

wherein the parameter interpolator (140; 260) is configured to determine a direction of the interpolation between the phase values (256) of subsequent complex-valued upmix parameters such that an angle-range passed in the interpolation between a phase value of the first complex-valued upmix parameter (142) and a phase value of the second complex-valued upmix parameter (144) is smaller than, or equal to, 180°.

2. An apparatus (100; 200) for upmixing a downmix audio signal (110; 210) describing one or more downmix audio channels into an upmixed audio signal (120; 214) describing a plurality of upmixed audio channels, the apparatus comprising:

an upmixer (130; 230) configured to apply temporally variable upmix parameters (150; 262; Hij) to upmix the downmix audio signal (110; 210) in order to obtain the upmixed audio signal (120; 214); and

a parameter interpolator (140; 260), wherein the parameter interpolator is configured to obtain one or more temporally interpolated upmix parameters (150; 262) to be used by the upmixer (130; 230) on the basis of an information describing a first complex-valued upmix parameter (142) and a subsequent second complex-valued upmix parameter (144),

wherein the parameter interpolator (140; 260) is configured to separately interpolate

(a) between a magnitude value (254) of the first complex-valued upmix parameter (142) and a magnitude value (254) of the second complex-valued upmix parameter (144), and
(b) between a phase value (256) of the first complex- valued upmix parameter (142) and a phase value (256) of the second complex-valued upmix parameter (144),

to obtain the one or more temporally interpolated complex-valued upmix parameters (150; 262);

wherein the parameter interpolator (140; 260) is configured to combine the separately interpolated magnitude values (274) and phase values (276) by applying a complex-valued rotation to the interpolated magnitude values (274), wherein an angle of the complex-valued rotation is determined by the interpolated phase values (276).

3. A method for upmixing a downmix audio signal (110; 210) describing one or more downmix audio channels into an upmixed audio signal (120; 214) describing a plurality of upmixed audio channels, the method comprising:

applying temporally variable upmix parameters (150; 262; Hij) to upmix the downmix audio signal (110; 210) in order to obtain the upmixed audio signal (120; 214); and

obtaining one or more temporally interpolated upmix parameters (150; 262) to be used by the upmixer (130; 230) on the basis of an information describing a first complex-valued upmix parameter (142) and a subsequent second complex-valued upmix parameter (144),

wherein the method comprises separately interpolating

(a) between a magnitude value (254) of the first complex-valued upmix parameter (142) and a magnitude value (254) of the second complex-valued upmix parameter (144), and
(b) between a phase value (256) of the first complex- valued upmix parameter (142) and a phase value (256) of the second complex-valued upmix parameter (144),

to obtain the one or more temporally interpolated complex-valued upmix parameters (150; 262);

wherein the method comprises determining a direction of the interpolation between the phase values (256) of subsequent complex-valued upmix parameters such that an angle-range passed in the interpolation between a phase value of the first complex-valued upmix parameter (142) and a phase value of the second complex-valued upmix parameter (144) is smaller than, or equal to, 180°.

4. A method for upmixing a downmix audio signal (110; 210) describing one or more downmix audio channels into an upmixed audio signal (120; 214) describing a plurality of upmixed audio channels, the method comprising:

applying temporally variable upmix parameters (150; 262; Hij) to upmix the downmix audio signal (110; 210) in order to obtain the upmixed audio signal (120; 214); and

obtaining one or more temporally interpolated upmix parameters (150; 262) to be used by the upmixer (130; 230) on the basis of an information describing a first complex-valued upmix parameter (142) and a subsequent second complex-valued upmix parameter (144),

wherein the method comprises separately interpolating
(a) between a magnitude value (254) of the first complex- valued upmix parameter (142) and a magnitude value (254) of the second complex-valued upmix parameter (144), and
(b) between a phase value (256) of the first complex- valued upmix parameter (142) and a phase value (256) of the second complex-valued upmix parameter (144),

to obtain the one or more temporally interpolated complex-valued upmix parameters (150; 262);

wherein the method comprises obtaining the separately interpolated magnitude values (274) and phase values (276) by applying a complex-valued rotation to the interpolated magnitude values (274), wherein an angle of the complex-valued rotation is determined by the interpolated phase values (276).

5. A parameter determinator (140; 260) for determining temporally variable upmix parameters for upmixing a downmix audio signal (110; 210) describing one or more downmix audio channels into an upmixed audio signal (120; 214) describing a plurality of upmixed audio channels,

wherein the parameter determinator comprises a parameter interpolator,

wherein the parameter interpolator is configured to obtain one or more temporally interpolated upmix parameters (150; 262) to be used by an upmixer (130; 230) on the basis of an information describing a first complex-valued upmix parameter (142) and a subsequent second complex-valued upmix parameter (144),

wherein the parameter interpolator (140; 260) is configured to separately interpolate
(a) between a magnitude value (254) of the first complex-valued upmix parameter (142) and a magnitude value (254) of the second complex-valued upmix parameter (144), and
(b) between a phase value (256) of the first complex- valued upmix parameter (142) and a phase value (256) of the second complex-valued upmix parameter (144),

to obtain the one or more temporally interpolated complex-valued upmix parameters (150; 262);

wherein the parameter interpolator (140; 260) is configured to determine a direction of the interpolation between the phase values (256) of subsequent complex-valued upmix parameters such that an angle-range passed in the interpolation between a phase value of the first complex-valued upmix parameter (142) and a phase value of the second complex-valued upmix parameter (144) is smaller than, or equal to, 180°.

6. A parameter determinator (140; 260) for determining temporally variable upmix parameters for upmixing a downmix audio signal (110; 210) describing one or more downmix audio channels into an upmixed audio signal (120; 214) describing a plurality of upmixed audio channels,

wherein the parameter determinator comprises a parameter interpolator,

wherein the parameter interpolator is configured to obtain one or more temporally interpolated upmix parameters (150; 262) to be used by an upmixer (130; 230) on the basis of an information describing a first complex-valued upmix parameter (142) and a subsequent second complex-valued upmix parameter (144),

wherein the parameter interpolator (140; 260) is configured to separately interpolate
(a) between a magnitude value (254) of the first complex-valued upmix parameter (142) and a magnitude value (254) of the second complex-valued upmix parameter (144), and
(b) between a phase value (256) of the first complex- valued upmix parameter (142) and a phase value (256) of the second complex-valued upmix parameter (144),

to obtain the one or more temporally interpolated complex-valued upmix parameters (150; 262);

wherein the parameter interpolator (140; 260) is configured to combine the separately interpolated magnitude values (274) and phase values (276) by applying a complex-valued rotation to the interpolated magnitude values (274), wherein an angle of the complex-valued rotation is determined by the interpolated phase values (276).
, Description:Attached herewith