Show dictionary · Video & LED
Glass-to-Glass
Glass-to-glass is the total delay from the camera lens (first glass) to the display surface (second glass): capture, processing, switching, transport, and display latency summed into one honest number, usually expressed in frames or milliseconds.
In practice
The phrase exists because per-device specs mislead: a camera, switcher, scaler, and LED processor each quoting "one frame" quietly stack into four. Live production measures the whole chain, classically by shooting a running clock and photographing source and screen together.
What counts as acceptable depends on the job: IMAG beside a live performer is the least forgiving, streaming adds seconds nobody on site perceives, and broadcast trucks manage it with systematic timing. The latency calculator on this site does the frames-to-milliseconds arithmetic per chain.
How you’ll hear it
"Measured glass-to-glass is five frames; lose the scaler and we are at four."
Related resources
Part of the eventools.io Show Dictionary, a free glossary of live event production terminology.