mleprince / web-edf-viewer

simple web edf viewer

EDF Viewer

!!! Work in progress !!!

This application display in the browser EDF files. Basic features are included : filters, gain, montages, zoom

Open the App

The aims of this project is to use and see limitations of :

• WebAssembly With Rust with crates Wasm_bindgen, web_sys and js_sys :
  • Parse EDF File
  • Apply filters and montages to the signals
  • generate the matrix of pixels of the chart
• File Api to read a local EDF File. The API is called through WebAssembly using Rust Crate web_sys
• Sound api to apply filters and montages to the signals => see below
• VueJS (with VueX and Typescript) First time I will use this framework

How to build

# compile webAssembly project
./worker/build.sh

# run application
cd ./app
npm run serve

FAQ

Why we cannot use WebAudio ?

I thought it will be possible to use WebAudio in the case of an ExG Viewer. This API provide all the components used by a viewer : IIR Filtering, Gain and combination of multiples signals ( montages ). However, this API is used for Audio files and Chromium has limitation about the sampling rate of the signal (between 3000Hz and 384000Hz) :

signalTransormer.ts:10 Uncaught DOMException: Failed to execute 'createBuffer' on 'BaseAudioContext': The sample rate provided (100) is outside the range [3000, 384000].

Why using Rust and not AssemblyScript as WebAssembly language ?

AssemblyScript was a good candidate because we can use the same language for JS frontend and WASM backend. However the library is yound and lacks of some important features :

• We cannot call Wasm functions from JS ( and JS function from Wasm) with arguments other than primitive types.The rust crate Wasm Bindgen has already this feature.
• There is no builtin fonctions to call Web APIs and DOM API.Wasm Bindgen. The rust crate web_sys implements bindings for all of these APIs.