📦 WebAssembly HEIF decoder

A dependency-free HEIF decoder written in WebAssembly

It decodes HEIF-encoded image data in a Uint8Array containing raw RGB pixels.

Installation

yarn add @saschazar/wasm-heif

or

npm install --save @saschazar/wasm-heif

Usage

It supports usage in the browser, in a Web Worker and of course Node.js.

// Node.js
import wasm_heif from '@saschazar/wasm-heif';

// Web Worker - see: https://developer.mozilla.org/en-US/docs/Web/API/WorkerGlobalScope/importScripts
importScripts('wasm_heif.js');

// -------- Browser/Web Worker/Node.js code below --------

// Load encoded HEIF image data in Uint8Array
const array = new Uint8Array(['some', 'encoded', 'heif', 'image', 'data']);
let result;

// Initialize the WebAssembly Module
const heifModule = wasm_heif({
  onRuntimeInitialized() {
    const alpha = false; // RGBA somehow not yet working ¯\_(ツ)_/¯
    result = heifModule.decode(array, array.length, alpha); // decode image data and return a new Uint8Array
    heifModule.free(); // clean up memory after encoding is done
  },
});

⚠️ Support

Although libheif provides support for decoding HEIF images into an RGBA buffer, none of the respective tests has succeeded yet. Therefore, it is crucial to compare the channels property of the object returned from the dimensions() function, when alpha was set to true in the decode() function.

Not all HEIF/HEIC-encoded images seem to be supported, as there have occurred failures while attempting to decode sample images from the nokiatech/heif repository.

However, images encoded on Cloudinary and/or fetched as HEIF/HEIC using the fetch_format parameter seem to work well.

Status

The main backbone of the project is the libheif library.

Currently only HEIF decoding using libde265 is enabled.

Help needed

Concerning the encoding functionality, a few trials have been made towards using the x265 encoder, but as of now, there doesn't seem to be a possibility for compiling it in an Emscripten-compatible way.

Credits

This module uses the strukturag/libheif's source code and most of the code is written according to the examples provided in that repository.

License

Licensed under the MIT license.

Copyright ©️ 2020—2021 Sascha Zarhuber