Delayed orientation signalling for immersive communications
There is disclosed apparatus for encoding a spatial audio scene comprising means configured to: determine, for an audio frame of at least one audio signal of the spatial audio scene, a change to the orientation of the apparatus, wherein the change to the orientation of the apparatus is respect to an orientation of the apparatus from a previous audio frame of the at least one audio signal, wherein the change to the orientation of the apparatus forms at least one orientation change value which forms at least part of an orientation change data set; determine an orientation change delay time for the change to the orientation of the apparatus, wherein the orientation delay time forms a further part of the orientation change data set; and perform the change to the orientation of the apparatus after a period of time specified by the orientation change delay time.
1 . An apparatus for decoding a spatial audio scene, comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to:
receive an orientation change data set, wherein the orientation change data set comprises: at least one orientation change value specifying a change to an orientation of the apparatus with respect to the spatial audio scene comprising at least one audio signal; and an orientation change delay time for the change to the orientation of the apparatus; and
perform the change to the orientation of the apparatus, wherein the change to the orientation of the apparatus is performed within a period of time specified by the orientation change delay time, wherein the apparatus caused to perform the change to the orientation of the apparatus is caused to determine an increment of change with respect to the at least one orientation change value.
2 . The apparatus as claimed in claim 1 , wherein the orientation change delay time is expressed in units of audio frames of the at least one audio signal.
3 . The apparatus as claimed in claim 1 , wherein the increment of change is a linear increment of change, wherein the apparatus caused to determine the increment of change is caused to determine a factor relating to a ratio of the at least one orientation change value to the orientation delay time.
4 . The apparatus as claimed in claim 1 , wherein the apparatus caused to perform the change to the orientation of the apparatus is further caused to:
apply the increment of change to the orientation of the apparatus on an audio frame by audio frame basis of the at least one audio signal for the period of time specified by the orientation change delay time.
5 . The apparatus as claimed in claim 1 , wherein the apparatus comprises a signal activity detection function, and wherein the apparatus caused to perform the change to the orientation of the apparatus if further caused to:
apply the increment of change to the orientation of the apparatus on an audio frame by audio frame basis of the at least one audio signal when the signal activity function indicates an active audio signal state; and
apply a change to the orientation of the apparatus such that the at least one orientation change value is reached over a period of an audio frame of the at least one audio signal when the signal activity detection function indicates an inactive audio signal.
6 . The apparatus as claimed in claim 1 , wherein the apparatus caused to perform the change to the orientation of the apparatus comprises is further caused to:
override the change to the orientation of the apparatus by not performing the change to the orientation of the apparatus.
7 . The apparatus as claimed in claim 1 , wherein the at least one orientation change value comprises at least one of: an azimuth value, an elevation value and a roll value.
8 . The apparatus as claimed in claim 1 , wherein the orientation change data set is received in the form of a Real-Time Transport Protocol (RTP) header extension according to RFC8285.
9 . The apparatus as claimed in claim 8 , wherein the RTP header extension comprises a L field according to RFC 8285, and wherein a value of the L field indicates that the RTP header extension contains at least one of the azimuth value, the elevation value, the roll value and the orientation change delay time.
10 . The apparatus as claimed in claim 8 , wherein the RTP header extension is a one-byte header extension according to RFC8285.
11 . A method for decoding a spatial audio scene, comprising:
receiving an orientation change data set, wherein the orientation change data set comprises: at least one orientation change value specifying a change to an orientation of an apparatus with respect to the spatial audio scene comprising at least one audio signal; and an orientation change delay time for the change to the orientation of the apparatus; and
performing the change to the orientation of the apparatus, wherein the change to the orientation of the apparatus is performed within a period of time specified by the orientation change delay time, wherein performing the change to the orientation of the apparatus comprises determining an increment of change with respect to the at least one orientation change value.
12 . The method as claimed in claim 11 , wherein the orientation change delay time is expressed in units of audio frames of the at least one audio signal.
13 . The method as claimed in claim 11 , wherein the increment of change is a linear increment of change, wherein determining the increment of change comprises determining a factor relating to a ratio of the at least one orientation change value to the orientation delay time.
14 . The method as claimed in claim 11 , wherein performing the change to the orientation of the apparatus further comprises:
applying the increment of change to the orientation of the apparatus on an audio frame by audio frame basis of the at least one audio signal for the period of time specified by the orientation change delay time.
15 . The method as claimed in claim 11 , wherein the apparatus comprises a signal activity detection function, and wherein performing the change to the orientation of the apparatus further comprises:
applying the increment of change to the orientation of the apparatus on an audio frame by audio frame basis of the at least one audio signal when the signal activity function indicates an active audio signal state; and
applying the change to the orientation of the apparatus such that the at least one orientation change value is reached over a period of an audio frame of the at least one audio signal when the signal activity detection function indicates an inactive audio signal.
16 . The method as claimed in claim 11 , wherein performing the change to the orientation of the apparatus further comprises:
overriding the change to the orientation of the apparatus by not performing the change to the orientation of the apparatus.
17 . The method as claimed in claim 11 , wherein the at least one orientation change value comprises at least one of: an azimuth value, an elevation value and a roll value.
18 . The method as claimed in claim 11 , wherein the orientation change data set is received in the form of a Real-Time Transport Protocol (RTP) header extension according to RFC8285.
19 . The method as claimed in claim 18 , wherein the RTP header extension comprises a L field according to RFC 8285, and wherein a value of the L field indicates that the RTP header extension contains at least one of the azimuth value, the elevation value, the roll value and the orientation change delay time.
20 . The method as claimed in claim 18 , wherein the RTP header extension is a one-byte header extension according to RFC8285.