JPL Spatial Application

Application demonstrating some of the capabilities of JPL Spatial.

The GUI is drawn using Dear ImGui library with a custom framework on top.

JPL Spatial Features

• Direct Sound (DS) Propagation & Spatialization
• Ray Traced Early (Specular) Reflections (ERs) (experimental)

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• Pannign of Direct Sound source is handled by MDAP (multiple directions)
• Early Reflections are traced using Image Source method and panned by VBAP (single directoin per ER)
• Propagation delay for both, DS and ERs, is rendered by Interpolating Delay Lines
• Propagation filtering (ER surface absorption, DS/ER air absorption) is processed by 4-band Crossover Filters
• Inverse law distance attenuation is applied to both DS and ERs

JPL Spatial Application Features

VBAP/MDAP Visualization

Direct Sound source's MDAP has "all" the expected parameters exposed to GUI:

• Focus - contract direction vectors towards source the channel directions
• Spread - contract all the direction vectors toward the source pan direction
• Source Size - if Spread From Source Size is enabeld, the size of the source is used to compute Spread based on distance from the listener
• Spread From Height - as the source gets closer to "directly above" or "directly below", spread minimum value goes towards 1.0 (100%)
• Source Orientation - whether to use source orientation for spatialization or not
  • when source orientation IS used, the source becomes more like a sound field in the world space
  • when source orientaion is NOT used, the source's frame is rotated towards the listener

Tip

Source and Output Channel Configuration can be disconnnected form the playing audio to visualize panning for configurations that may not be available on the user's device.

Sound Source Playback

• Sound Source can be selected in the "Sound Sources" tab/window
  • a few audio files are available in the repository (and in the release)
  • sound source directory can be selected to play different files
• Audio Player has waveform view and all the expected playback controlls
• Loudness Meter displays Peak and RMS loundess of the application output; the big number at the top displays current RMS value

Room / Environment Controls

Room (everything is in 3 dimensions):

• Room size
• Source position
• Listener position

Early Reflections (aka Specular Reflections, not that early at high order):

• Max Reflection Order - maximum allowed reflection order to trace
• Surface Material - changes the material absorption applied to reflected ER paths
• Number of Primary Rays - mainly needed to balance performace vs source detection possiblility (for a simple shoe-box room, its 6 surfaces can easily be detected with a small number of rays)

Tip

Spatialziation Effects can be enabled/disabled individuslly for the Direct Sound to hear the effect with/without them.

Specular Reflections and Directo Sound can also be muted individually.

Supported platforms

• Currently Windows only
• Other platforms may or may not work

Building

• To build the application, run appropriate build script in build folder, open generated Visual Studio solution and compile relevant configuration.
• Uses C++20

Dependencies

• JPL Spatial - sound spatialization and propagaion - ISC license
• MiniaudioCpp - routing and rendering audio to endpoint device - ISC license
• Walnut (CMake fork) - platfom window handling and some application utilities - MIT license

License

The project is distributed under the LICENSE.

Third-Party Assets

• JPL Spatial Application uses IBM Plex Sans font licensed under the SIL Open Font License 1.1. Copyright (c) 2017 IBM Corp. with Reserved Font Name "IBM Plex".
• A few icons are used from Font Awesome (free) under the SIL Open Font License 1.1.