Understanding WebGL Video Scrubbing

When building interactive media experiences on the web, users expect instant, fluid control when scrubbing through a video timeline. However, standard HTML5 video elements are designed for linear playback. When a user rapidly drags a time slider, standard streaming creates a bottleneck of cancelled network requests and heavy decoding lag.

To achieve frame-accurate, zero-latency scrubbing, two critical pieces must align:

1. The Video Encoding (GOP = 1): Standard codecs save space by calculating changes between frames, forcing the browser to perform heavy math during a seek. By encoding the video with a GOP of 1 (All-Intra), every single frame becomes an independent keyframe, allowing instant visual access.
2. The Memory Strategy (RAM Caching): Instead of relying on live streaming which stutters under rapid input, downloading the entire file upfront into a local memory Blob completely bypasses network latency.

By combining a properly encoded MP4 file with an optimized WebGL texture operator (VideoTextureScrub), developers can achieve perfectly smooth, responsive video control in real-time.