X3D version 4.0 was approved by Web3D Consortium and ISO in 2023.[/X3D, diagnostic]
X3D version 4.0 offers many new features including interoperability with HTML5, glTF
2.0 Physically Based Rendering (PBR), and Web Audio API.[/X3D, diagnostic]
<meta name='info' content='This work presents an innovative solution of the spatial
sound in X3DOM framework,
that based on a combinational methodology. Specifically, we suggested the enrichment
of X3DOM with spatial sound features, using both the X3D sound nodes and the structure
of Web Audio API.'/> [/X3D/head/meta[3], diagnostic]
<meta name='TODO' content='credit for audio files'/> [/X3D/head/meta[8], diagnostic]
<Viewpoint DEF=''/> is missing description which is important for accessibility and
usability.  Example:
description='initial view, rotate to examine object' [/X3D/Scene/Viewpoint, warning]
<ImageTexture DEF=''/> url array address(es) duplicate the url definition found in
a preceding node,
consider DEF/USE to reduce download delays and memory requirements for url content
(url='"images/line.png" "https://www.web3d.org/x3d/content/examples/X3dForAdvancedModeling/AudioSpatialSound/images/line.png"')
[/X3D/Scene/Transform[2]/Transform[2]/Shape/Appearance/ImageTexture, warning]
<Gain USE='ChannelSplitter'/> found USE node that precedes matching DEF node, count(following::*[@DEF=$USE])=1[/X3D/Scene/StreamAudioDestination/Gain/ChannelMerger/ChannelSelector[1]/Gain, error]
<Gain USE='ChannelSplitter'/> node type must match node type of original <ChannelSplitter
DEF='ChannelSplitter'/> [/X3D/Scene/StreamAudioDestination/Gain/ChannelMerger/ChannelSelector[1]/Gain, error]
<Gain USE='ChannelSplitter'/> found USE node that precedes matching DEF node, count(following::*[@DEF=$USE])=1[/X3D/Scene/StreamAudioDestination/Gain/ChannelMerger/ChannelSelector[2]/Gain, error]
<Gain USE='ChannelSplitter'/> node type must match node type of original <ChannelSplitter
DEF='ChannelSplitter'/> [/X3D/Scene/StreamAudioDestination/Gain/ChannelMerger/ChannelSelector[2]/Gain, error]
<AudioClip DEF=''/> url array does not contains link to .wav or .midi sound files,
browsers not required
to support other formats (url='"sound/violin.mp3" "https://www.web3d.org/x3d/content/examples/X3dForAdvancedModeling/AudioSpatialSound/sound/violin.mp3"')
[/X3D/Scene/ChannelSplitter/AudioClip, warning]