ReferenceError: Can't find variable: OffscreenCanvas. ReferenceError: Can't find variable: document.

[Talb2005]

• I have verified that the issue occurs with the latest twilio-video-processors.js release and is not marked as a known issue in the CHANGELOG.md.
• I reviewed the Common Issues and open GitHub issues and verified that this report represents a potentially new issue.
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  or sensitive account information (API keys, credentials, etc.) when reporting this issue.

Our Sentry logs show that multiple users are encountering the following errors when using @twilio/video-processors version 3.0.0.

• ReferenceError: Can't find variable: OffscreenCanvas
• ReferenceError: Can't find variable: document

The ReferenceError: Can't find variable: OffscreenCanvas occurs when instantiating the BackgroundProcessor in:

@twilio/video-processors/lib/processors/background/BackgroundProcessor.ts in BackgroundProcessor at line 84:61
private readonly _inputFrameCanvas: OffscreenCanvas = new OffscreenCanvas(1, 1);

The ReferenceError: Can't find variable: document occur in twilio-virtual-background-processor-pipeline-worker.js and twilio-gaussian-blur-background-processor-pipeline-worker.js in:

function getCanvas() {
    return typeof OffscreenCanvas !== 'undefined' ? new OffscreenCanvas(1, 1) : document.createElement('canvas');
}

We are using the const isSupported from '@twilio/video-processors' to prevent non-supported browsers from using this feature, so these user agents are supposed to be supported.

• On macOS, the errors occur on Safari <= 16.3.
• On iPad, the errors occur on iOS / iPadOS <=16.3.1

This is probably related to the fact that Safari started supporting OffscreenCanvas only in version 16.4.

If document.createElement('canvas'); is called from within a web worker, then the document won't be available, hence the ReferenceError: Can't find variable: document

• Browser(s): Safari <=16.3, any browser using WebKIT while iOS <=16.3.1.
• Operating System: macOS - Safari <=16.3, iOS / iPadOS <=16.3.1
• twilio-video-processors.js: 3.0.0
• Third-party libraries (e.g., Angular, React, etc.): Angular