Core descriptors

The following descriptors are currently proposed as core descriptors.
Core descriptors should be understood by every SpatDIF compliant renderer.

Entities

The core descriptors can be assigned to different entities. The following entities are proposed:

  • Source, a virtual sound source, emitting sound into the scene.
  • Listener, a virtual sound sink, receiving sound from the scene.
  • Loudspeaker, a real sound source, outputting sound from the scene into the real world
  • The index of these entities starts with the number 1.
  • Draft SpatDIF OSC-commands would be:
/spatdif/core/source/4/gain -12.0 db

/spatdif/core/listener/1/position 0.5 -0.5 0.0

/spatdif/core/speaker/8/position -67.5 0.0 1.0 aed

Position

  • We propose one default coordinate system for describing position data
  • A draft SpatDIF OSC-command would be:
/spatdif/core/source/1/position 1.0 2.4 3.0
  • It is not decided what this default coordinate system would be.
  • We also allow for using a few alternative coordinate systems:
  • A draft SpatDIF OSC-command for using a spherical system could be:
/spatdif/core/source/1/position 1.0 2.4 3.0 aed
  • The alternative coordinate system is specified through the string at the end of this message
  • In the final SpatDIF specification all alternatives and their related reserved strings are going to be defined
  • The alternative coordinate system is only temporarily valid for this specific description
  • It is not decided what these alternative coordinate systems are, here are the proposed coordinate systems

see poll results for included coordinate systems Poll Results

Offset feature

  • The idea is to have an absolute origin of the Coordinate System, then work with local coordinate system offsets.
  • This Concept belongs to geo-transform extension Geo-transform_Extension.

Gain Units

  • similarly the gain description is proposed, we propose one default gain unit.
  • a draft SpatDIF OSC-command would be:
/spatdif/core/source/1/gain 0.9
  • It is not decided what this default gain unit will be, (probably linear gain)
  • We also allow for using a few alternative gain units
  • A draft SpatDIF OSC-command would be:
/spatdif/core/source/1/gain -6.2 db
  • The alternative gain unit is specified through the string at the end of this message
  • In the final SpatDIF specification all alternatives and their related reserved string are going to be defined
  • The alternative gain unit is only temporarily valid for this specific description
  • It is not decided yet what these alternative gain units are, here are the proposes gain descriptors
  • See poll results for included gain descriptors Poll Results*

Distance attenuation

(not defined yet)

  • A distance according to the position data should be simulated by an attenuation according to the inverse square law
  • A maximum amplification due to proximity to the reference position can be defined
    o (e.e, not further amplification if sound is closer than 1 meter to reference position)
  • Alternatively, other distance functions can be applied, e.g. to adapt for different listening environments
  • it is not decided what these alternative distance functions are