Stream to canvas vs. image?

[jas-]

This is an awesome library.

Have you thought about adding streaming support? Something that might tie into data retrieved from a USB SDR device?

I suppose an SVG rendered in a canvas element would be the best method of converting the FFT to something visual? The new'ish Path2D API might be the easiest route based on what I have looked at with the worker image generation code you have already written.

[zuckschwerdt]

Thanks. Streaming could be available soon. This JS implementation is maintainance only now and a much faster (about 10x) and more versatile WASM implementation to replace this is about half done.

I did some tests with a GPU based implementation and it looked like loading the SDR data as textures costs too much time to be worth it. I might try that again when the new implementation is ready.

[jas-]

wasm would be the best way to visualize a stream like those provided by a USB dongle. Is that a public repo?

[zuckschwerdt]

The computational performance of WASM really shines. And with optimizations like zero-copying data in (from file ReadableStreamBYOBReader should do) and output to OffscreenCanvas (still needs better support) it's near native performance and should be good for real-time.
There is no repo, just a bunch of concept tests to get the needed kit together. Expect something in maybe a month or two.

[jas-]

Well if you want someone to help test things let me know. I might be able to contribute code as well.

[zuckschwerdt]

Thanks. I'll try to get a bare bones repo put together soon. There is a, mostly debug, demo at https://triq.org/spectrogram-next/ now. You can observe the full recomputation/redraw speed by scroll-zoom or scrolling though gain and color map -- and that's not even using a worker.

[zuckschwerdt]

Oh, I just checked again and current Firefox 105 now also seems to supports OffscreenCanvas. Though MDN still shows support as nightly and no OffscreenCanvasRenderingContext2D support.

[romanziske]

Hi there!

I hope this message finds you well. I'm writing to ask if you have any updates on when the next version of the library will be released.

[zuckschwerdt]

Really soon now. The preview https://triq.org/spectrogram-next/ only has minor todos left.
Are you interested in https://triq.org/pdv/ or some similar integration or do you need live streaming?