Live broadcasts are frequently not quite live. A deliberate delay is inserted before transmission, and its existence explains several oddities in how sport is experienced at home.
The delay is an editing window
Holding the signal for a short period gives a director time to cut away from an incident, mute audio or drop a shot before it reaches the audience.
The situations it covers are predictable in kind if not in occurrence: crowd behaviour, serious injury, pitch incursion and language picked up by field microphones.
Without the window, the only remedy is apology afterwards, which regulators in several countries treat as insufficient for content that should never have aired.
Technical delay accumulates separately
Encoding, distribution and player buffering each add their own increment, and those are unavoidable consequences of moving compressed video across networks.
The intentional editing delay sits on top, so the total offset a viewer experiences is the sum of a design decision and a set of engineering constraints.
Different distribution paths accumulate different totals, which is why two viewers watching the same match on different services see it seconds apart.
Data feeds bypass the delay entirely
Score services carry no pictures and no risk of transmitting something unacceptable, so nothing in their path justifies holding a message back for editorial reasons.
The result is that a notification arrives while the broadcast is still showing the build-up, spoiling the moment for a viewer holding a phone.
Betting markets face the sharper version of this, which is why in-play markets are suspended around events rather than priced against a delayed picture.
Venue audiences are ahead of everyone
Spectators in the ground see events with no delay at all, so their reaction reaches social media before the broadcast reaches its own viewers.
Stadium screens showing replays are sometimes fed from the same delayed chain, producing the strange effect of a crowd reacting before the screen catches up.
Venues generally take a direct feed to avoid that, which means the pictures inside the ground and the pictures at home are different in timing and sometimes in content.
Reducing the delay has consequences
Low-latency streaming shrinks the buffer to close the gap, which improves synchronisation but makes playback more vulnerable to network variation.
Cutting the editorial window instead transfers risk to the broadcaster, which is a decision made by compliance departments rather than by engineers.
Most services settle on a compromise, accepting a few seconds of offset as the price of both stability and the ability to intervene when something goes wrong.
