Multimodal models need video. We froze time to give it to them

posthog.com · 1 month ago · 11

Replay Vision built a rasterizer to convert rrweb session replays into MP4 video so multimodal models could correctly “watch” them. It since March 2026 has rasterized more than 370 years of recordings into roughly 3.5 million videos. By gating Chrome’s frame rendering with HeadlessExperimental.beginFrame and freezing the rrweb player’s virtual time, the service eliminates skipped or frozen outputs so CPU contention only changes job duration, not the resulting video.