This clause defines scene processing capabilities that enable AR and XR experiences. In clause 9.2, glTF-based Scene Description capabilities are defined.

This clause defines client cababilities for rendering and presenting Scene Description based on glTF2.0 [10]. Additional extended capabilites are defined, primarily to support real-time media based on the extensions defined in the MPEG-I Scene Description in ISO/IEC 23090-14 [11] - [13]. The following scene processing capabilities are defined.

• SD-Rendering-glTF-Core: The capability to process glTF2.0 [10] scene description files and to render the described scenes with the following restrictions:
  • The glTF 2.0 scene description can either be a standalone JSON file or an encapsulated GLB file.
  • The glTF 2.0 scene description can have an aggregate geometry complexity, including all mesh primitives of the scene, of at least 100k faces and/or points. The requirement on the number of faces in mesh nodes allows for moderate complexity scenes.
  • The glTF 2.0 scene description can have at least 20 materials using static image textures. The requirement on the number of materials with image texture maps allows for moderate complexity scenes.
  • The glTF 2.0 scene description can use glTF2.0 animations and skinning.
  • The glTF 2.0 scene description can use the KHR_lights_punctual and KHR_materials_specular extensions.
• SD-Rendering-glTF-Ext1: On top of the SD-Rendering-glTF-Core capability, the capability to process MPEG-I Scene Description documents as specified in [11] - [13] and to render the described scenes with the following restrictions:
  • The MPEG-I Scene Description document can use the MPEG_media extension.
  • The MPEG-I Scene Description document can use the MPEG_accessor_timed and the MPEG_buffer_circular extensions.
  • The MPEG-I Scene Description document can use the MPEG_texture_video extension.
  • The MPEG-I Scene Description document can use the MPEG_audio_spatial extension.
  • The MPEG-I Scene Description document can use the scene description update mechanism as defined in clause 5.2.4 of [9].
  • Processing of scene description updates as defined in ISO/IEC 23090-14 [11] - [13] to allow the device to contribute to a scene description of a dynamic shared scene.
  • The MPEG-I Scene Description document can use at least 4 materials using video textures
  • The MPEG-I Scene Description document may use at least 4 object-based mono audio sources, which allows for relatively simple audio support.
• SD-Rendering-glTF-Ext2: On top of the SD-Rendering-glTF-Core capability, the capability to process MPEG-I Scene Description documents as specified in [11] - [13] with the following restrictions:
  • The MPEG-I Scene Description document can use the MPEG_anchor extension.
  • The MPEG-I Scene Description document can use the EXT_lights_image_based and the MPEG_lights_texture_based extensions.
• SD-Rendering-glTF-Interactive: On top of the SD-Rendering-glTF-Core capability, the capability to process the following glTF 2.0 extensions defined in [11] - [13] to enable user input and local interaction processing.
  • The MPEG-I Scene Description document can use the MPEG_scene_interactivity extension with the following triggers: TRIGGER_USER_INPUT, TRIGGER_PROXIMITY, TRIGGER_COLLISION, TRIGGER_VISIBILITY.
  • The MPEG-I Scene Description document can use the MPEG_scene_interactivity extension with actions: ACTION_ACTIVATE, ACTION_TRANSFORM, ACTION_BLOCK, ACTION_ANIMATION, ACTION_MEDIA, ACTION_MANIPULATE, ACTION_SET_MATERIAL