Why Chrome is King for Web Video Export

If you use Kinetix to export a 4K video on Google Chrome, it takes about 10 seconds. If you try the same export on Firefox, it might take 2 minutes, or crash.

Why the huge difference? And how do we handle it?

The Engine: WebCodecs

Kinetix uses the modern WebCodecs API to encode video directly in the browser. This allows us to access the hardware video encoder (NVENC on Nvidia, VideoToolbox on Mac) without any server-side rendering.

Chromium (Chrome, Edge, Brave)

Chromium has the most mature implementation of VideoEncoder.

Hardware Acceleration: Native support for H.264 and VP9.
Speed: Can process frames as fast as the GPU allows.
Stability: Handles large buffers (4K textures) gracefully.

Firefox (Gecko)

Firefox supports WebCodecs (as of version 130+), but the implementation varies significantly by OS.

on many Windows machines, it falls back to Software Encoding (OpenH264), which eats CPU and freezes the main thread.
memory management for large ImageBitmap transfers is stricter, leading to frequent allocation failures during heavy exports.

Safari (WebKit)

Safari’s implementation is relatively new and often lacks support for specific container muxing features we rely on for standard MP4s.

The UX Solution: Smart Warnings

We don’t want to block Firefox users, but we owe them a heads-up. We implemented a BrowserDetector to check the environment before export.

// utils/BrowserDetector.ts
export class BrowserDetector {
    static isChromium(): boolean {
        // Feature detection + UA check for Chromium engine
        return !!window.chrome && !navigator.userAgent.includes('Firefox');
    }
}

If a user tries to export on a non-Chromium browser, we inject a friendly warning into the UI:

Recommended Browser You are using Firefox. Video export is experimental on this browser. For 20x faster exports and better stability, please use Google Chrome or Microsoft Edge.

Implementation

We added this check directly to our ExportDialog component.

// EditorLayout.tsx
{isBrowserWarning && (
    <div className="bg-orange-50 text-orange-800 p-4 rounded-xl">
        You are using {BrowserDetector.getBrowserName()}. 
        Switch to Chrome for better performance.
    </div>
)}

This simple check saves our users from frustration and reduces “My export crashed” support tickets by explaining the limitation upfront.

Summary

WebCodecs is the future, but browser support is uneven.
Chrome/Edge are currently the only reliable options for heavy 4K encoding.
User Education via in-app warnings is better than silent failures.