Dual Video Overlay
Dual Video Overlay runs video advertising directly on top of Mediaset España's live DTT broadcast signal, never replacing it. WebAssembly renders both streams at once, so there is no cut entering or leaving the ad, in either direction. Ads play silently as a movable overlay by default; one OK press expands them to fullscreen with audio. Placement uses AI-based scene detection (recaps, credits, audience close-ups, etc.), and a custom OGV format we negotiated directly with Google powers it inside Google Ad Manager.
Description
Traditional HbbTV ad formats replace or interrupt the broadcast signal, forcing a black screen or a hard cut away from the programme, a moment where many viewers lose engagement or switch channel. Dual Video Overlay solves this differently: a broadcast stream event triggers a second video stream directly on top of the live DTT signal, decoding both simultaneously with WebAssembly, so there is never a cut between advert and broadcast, in either direction. Before playing the ad, the device checks whether it supports WebAssembly, so the format only runs on capable hardware. By default, the overlay plays silently as a small, movable window; a single press of OK expands it to fullscreen with audio, and when the ad finishes, playback returns cleanly to the live broadcast. The overlay can be positioned anywhere on screen and in any aspect ratio, including 16:9 and 9:16. Placement is powered by AI-based scene detection, which identifies moments where an overlay will not compete with the content itself programme recaps, opening or closing credits, audience close-ups, among others rather than interrupting key narrative moments. Self-promotional content can be sent to all viewers; third-party advertising is only served to viewers who have accepted cookies through Mediaset's CMP. Delivering this required more than in-house engineering: we negotiated directly with Google to add OGV format support to Google Ad Manager, so GAM could serve the exact video format our WebAssembly player needs work that benefits the wider GAM ecosystem, not just Mediaset. Live in production since 19 June 2026, Dual Video Overlay has already run real advertising campaigns for multiple advertisers.
Impact
Eliminates the black-screen/interruption moment inherent to replacement-based ad formats, in both directions, thanks to WebAssembly's dual-stream rendering keeping viewers engaged with the underlying programme throughout the ad, not pulled away from it. Segmented delivery through Google Ad Manager brings genuinely personalised messaging to a format that is usually one-size-fits-all, and AI-driven placement protects the viewing experience by keeping ads out of key content moments. Real campaign data for the PIP format: the format is already whitelisted across 4.4 million unique HbbTV devices, with 52.6 million ad requests and 21.9 million total impressions served (~41.6% match rate), a ~2% OK-through (fullscreen) rate and a 98% completion rate well above typical online video benchmarks. The direct integration work with Google to bring OGV support into Google Ad Manager extends beyond Mediaset, a contribution to the wider GAM/HbbTV advertising ecosystem that other broadcasters can build on.
Screens
