Audio scene description and control
A data structure stored in memory includes a scene description that defines a hierarchy of scene components that are in digital audio content received from a producer. The hierarchy has several stages including a fourth stage in which a scene composition is defined that contains all scene components needed to render the digital audio content in a single presentation, for instance as intended by the producer, and for input to a spatial audio renderer, wherein the scene composition contains one or more composition selection groups. Other aspects are also described and claimed.
1 . A method for processing digital audio content for input to a spatial audio renderer, the method comprising:
receiving digital audio content from a producer, wherein the digital audio content comprises a plurality of scene components and a scene description, and the scene description defines a hierarchy of the plurality of scene components, the hierarchy comprising:
a first stage in which each of the plurality of scene components is grouped into either a language-specific item or a non-language item, not both, wherein there is at least two language-specific items or at least two non-language items in the first stage,
a second stage in which all language-specific items are members of one but not necessarily a same language selection set, there being one or more language selection sets,
a third stage in which one or more of the language selection sets are grouped into a composition selection group, and two or more of the non-language items are grouped into the same composition selection group or another composition selection group, wherein of all items that are in a single composition selection group no more than one is active at a time, and
a fourth stage in which a scene composition is defined that contains all of the plurality of scene components needed to render the digital audio content in a single presentation, for input to the spatial audio renderer, wherein the scene composition contains one or more of the composition selection groups; and
modifying at least some of the scene components in accordance with the scene description and in accordance with a user input to produce modified scene components for input to the spatial audio renderer.
2 . The method of claim 1 further comprising
decoding a bitstream to produce the digital audio content, wherein the bitstream was generated by an encoder-side process.
3 . The method of claim 1 further comprising
the spatial audio renderer rendering the modified scene components into a plurality of speaker driver signals that are to drive a plurality of speakers and thereby produce spatial sound of the digital audio content.
4 . The method of claim 1 wherein modifying at least some of the scene components comprises one or more of the following based on the user input:
muting one or more of the scene components;
changing but not muting an audio level of one or more of the scene components;
selecting one of several different language versions of one or more of the scene components; and
changing a rendering location of one or more of the scene components.
5 . The method of claim 1 wherein each language selection set contains two or more items being different language versions of a scene component, and of all items that are in a single language selection set no more than one is active at a time.
6 . The method of claim 1 wherein the scene description defines which scene components are modifiable by a user and which scene components cannot be modified, the method further comprising:
extracting one or more parts of the scene description and forwarding the extracted parts to a user interface, wherein the forwarded extracted parts define controls that the user interface exposes to the user; and
receiving the user input from the user interface.
7 . The method of claim 6 wherein a further scene composition is defined in the scene description that cannot be modified by user interaction.
8 . The method of claim 1 wherein the hierarchy comprises a fifth stage in which one or more composition selection groups are grouped into one or more categories.
9 . A memory for storing data for access by an application program being executed by a computer for processing digital audio content for input to a spatial audio renderer, the memory comprising:
a data structure stored in the memory, the data structure including a scene description that defines a hierarchy of a plurality of scene components that are in digital audio content from a producer, the hierarchy comprising:
a first stage in which each of the plurality of scene components is grouped into either a language-specific item or a non-language item, not both, wherein there is at least two language-specific items or at least two non-language items in the first stage,
a second stage in which all language-specific items are members of one but not necessarily a same language selection set, there being one or more language selection sets,
a third stage in which one or more of the language selection sets are grouped into a composition selection group, and two or more of the non-language items are grouped into the same composition selection group or another composition selection group, wherein of all items that are in a single composition selection group no more than one is active at a time, wherein an item is active when it is to be rendered in a single presentation of the digital audio content, and
a fourth stage in which a scene composition is defined that contains all of the plurality of scene components needed to render the digital audio content in the single presentation, for input to the spatial audio renderer, wherein the scene composition contains one or more composition selection groups.
10 . The memory of claim 9 wherein each language selection set contains two or more items being different language versions of a scene component, and of all items that are in a single language selection set no more than one is active at a time.
11 . The memory of claim 9 wherein the scene description defines which of the plurality of scene components are modifiable by a user and which of the plurality of scene components cannot be modified.
12 . The memory of claim 11 wherein upon one of the scene compositions defined in the scene description cannot be modified by user interaction.
13 . The memory of claim 9 wherein the hierarchy comprises a fifth stage in which one or more composition selection groups are grouped into one or more categories.
14 . The memory of claim 9 , wherein the spatial audio renderer is configured to render one or more scene components into a plurality of speaker driver signals that are to drive a plurality of speakers and thereby produce spatial sound of the digital audio content.
15 . A playback system for processing digital audio content, the playback system comprising:
a processor; and
memory having stored therein instructions that configure the processor to
receive digital audio content from a producer, wherein the digital audio content comprises a plurality of scene components and a scene description, and the scene description defines a hierarchy of the plurality of scene components, the hierarchy comprising:
a first stage in which each of the plurality of scene components is grouped into either a language-specific item or a non-language item, not both, wherein there is at least two language-specific items or at least two non-language items in the first stage,
a second stage in which all of the language-specific items are members of one but not necessarily a same language selection set, there being one or more language selection sets,
a third stage in which one or more of the language selection sets are grouped into a composition selection group, and two or more of the non-language items are grouped into said composition selection group or another composition selection group, wherein of all items that are in a single composition selection group no more than one is active at a time, and
a fourth stage in which a scene composition is defined that contains all of the plurality of scene components needed to render the digital audio content in a single presentation, for input to a spatial audio renderer, wherein the scene composition contains one or more of the composition selection groups; and
modify at least some of the plurality of scene components in accordance with the scene description and in accordance with a user input to produce modified scene components for input to the spatial audio renderer.
16 . The playback system of claim 15 wherein the processor is further configured to
decode a bitstream to produce the digital audio content, wherein the bitstream was generated by an encoder-side process.
17 . The playback system of claim 16 wherein the processor is further configured as the spatial audio renderer, rendering the modified scene components into a plurality of speaker driver signals that are to drive a plurality of speakers and thereby produce spatial sound of the digital audio content.
18 . The playback system of claim 17 wherein the processor modifying at least some of the scene components comprises one or more of the following based on the user input:
muting one or more of the scene components;
changing but not muting an audio level of one or more of the scene components;
selecting one of several different language versions of a scene component; and
changing a rendering location of a scene component.
19 . The playback system of claim 15 , wherein each language selection set contains two or more items being different language versions of a scene component, and of all items that are in a single language selection set no more than one is active at a time.
20 . The playback system of claim 15 , wherein the scene description defines which scene components are modifiable by a user and which scene components cannot be modified, the memory comprises further instructions to:
extract one or more parts of the scene description and forwarding the extracted parts to a user interface, wherein the forwarded extracted parts define controls that the user interface exposes to the user; and
receive the user input from the user interface.
21 . The playback system of claim 15 , wherein the hierarchy comprises a fifth stage in which one or more composition selection groups are grouped into one or more categories.