About web worker

[MarcoQQ]

Hi, do you know how to combine yuv-canvas with web-worker? It I want to use offscreen canvas, it seems that I have to rewrite yuv-canvas.

[bvibber]

My project produces frames in a web worker, postMessages them to the main thread (transferring the buffers to avoid additional copies), and then the main thread uses yuv-canvas directly.

I don't know anything about offscreen canvas or what that entails.

[wangzongxu]

I need to draw multiple videos on one page, but yuv-Canvas has a lot of calculation, which makes the page very slow.
I want to perform calculations in a Web worker. Can I do that

[hamburger-l]

I need to draw multiple videos on one page, but yuv-Canvas has a lot of calculation, which makes the page very slow. I want to perform calculations in a Web worker. Can I do that

解决了吗兄弟？

[mihailj]

Hello,

If anyone still needs an answer to this question: yes, it's possible to use yuv-canvas in a web worker with an offscreen canvas with some small changes.

This function now crashes if you try to use it in a web worker:

https://github.com/brion/yuv-canvas/blob/main/src/WebGLFrameSink.js#L472

It crashes because it cannot find the document, this object is not available in the web worker.

So you can move the feature detection outside of the web worker in the main thread, attach the status to a window global variable, example:

function webGLDetection() {
        // do the detection here...
	return true;
}

window.webGLAvailable = webGLDetection();

If you want you can copy the feature detection from the original WebGLFrameSink.isAvailable function with small changes.

Then you can modify the WebGLFrameSink.isAvailable function by using the window variable:

	WebGLFrameSink.isAvailable = function() {
		return window.webGLAvailable;
	}

Then in the web worker where you include the bundle script you need to declare the window variable before you include the JS file.

window = globalThis;

importScripts('./js/bundle.js');

Hope this helps to give you an idea and that I didn't miss anything.

Cheers,
Mihail