Adapters

HLS Downloader uses an adapter pattern to support different runtimes. Choose the adapter that matches your environment:

• Browser — WasmAdapter (FFmpeg WASM)
• Node.js — RustAdapter (Rust N-API native implementation)

Both adapters expose the same API through the HlsDownloader class. The only difference is the import path and initialization behavior.

WASM Adapter (Browser)

import { WasmAdapter } from '@hls-downloader/adapters/wasm'
// or
import { WasmAdapter } from '@logosw/hls-downloader/adapters/wasm'

The WASM adapter uses FFmpeg compiled to WebAssembly. During init(), it loads the FFmpeg core, WASM binary, and optionally a worker for multi-threading.

WASM-Specific Options

Pass these as part of the option object in the HlsDownloader constructor:

Option	Type	Description
coreURL	string	Custom FFmpeg core JS URL (defaults to CDN)
wasmURL	string	Custom FFmpeg WASM binary URL
workerURL	string	Custom FFmpeg worker URL
disableMultiThread	boolean	Use single-thread FFmpeg build (no worker)

Example

const downloader = new HlsDownloader({
  adapter: WasmAdapter,
  option: {
    coreURL: '/ffmpeg/ffmpeg-core.js',
    wasmURL: '/ffmpeg/ffmpeg-core.wasm',
    disableMultiThread: true,
  },
})

Rust Adapter (Node.js)

import { RustAdapter } from '@hls-downloader/adapters/rust'
// or
import { RustAdapter } from '@logosw/hls-downloader/adapters/rust'

The Rust adapter loads a native .node addon built with N-API. It provides better performance and path handling compared to the WASM adapter, making it the preferred choice for server-side usage.

Requirements

• Node.js ≥ 20
• The native .node binary must match your platform and Node ABI

Example

import { HlsDownloader } from '@hls-downloader/core'
import { RustAdapter } from '@hls-downloader/adapters/rust'

const downloader = new HlsDownloader({
  adapter: RustAdapter,
})

await downloader.init()

const result = await downloader.download({
  url: 'https://example.com/stream.m3u8',
  filename: 'output.mp4',
})

WARNING

Do not bundle the Rust adapter (native .node addon) into browser code. For browser bundles, only import the WASM subpath.