@some0neelse/get-webp-duration

Get WebP animation duration by parsing RIFF structure directly in the browser.

Installation

npm install @some0neelse/get-webp-duration

Usage

import { getWebPDurationMs } from '@some0neelse/get-webp-duration';

const duration = await getWebPDurationMs('https://example.com/animation.webp');
// Returns: number (duration in milliseconds) | 0 (static WebP) | null (error)

API

getWebPDurationMs(url: string): Promise<number | null>

Calculates the total duration of a WebP animation by analyzing its RIFF binary structure directly in the browser.

Parameters:

• url - URL of the WebP file

Returns:

• number - Total duration of all animation frames in milliseconds
• 0 - If WebP is valid but static (no ANIM/ANMF chunks)
• null - If the file cannot be loaded or doesn't match WebP format

Note: This calculates the "duration from file metadata", not the actual playback duration in browsers (browsers may override very small delays).

License

MIT