Free engineer tool
Sync Clock
A wall-clock timecode to stream. Measure glass-to-glass latency on any viewer, and align slides, captions and cues to the recording. Runs in your browser. No signup required.
Stream Certified · sync clock · local time
--:--:--.0
UTC --:--:--
Checking this clock against the server…
Embed in a graphics engine or vision mixer
Point any HTML5 web browser source at the link below. The background is transparent, so it keys straight over your programme. The clock runs on the machine rendering it and makes no network calls. It matches the Local / UTC, beep and grain settings above.
Tune it with query parameters: bg=black for a full-frame source (transparent otherwise), pos=tl|tr|bl|br to corner it, size=8 for smaller digits, label=0 to hide the caption, ring=0 to hide the second ring, and data=6 (0–10) to add a moving grain layer if a hardware encoder starves on the static image and the far end freezes. Example: https://streamcertified.com/sync-clock.html?bg=black&data=6
How to use it
Step 1
Put it in the picture
Open this page fullscreen on a laptop and feed its HDMI into the switcher, or straight into the encoder. The clock is now part of the programme.
Step 2
Read it back
Open the stream on any viewer next to that device’s own clock. Viewer clock minus the clock in the picture is your glass-to-glass latency on that network.
Step 3
Align the recording
On the recording, the clock in the picture is the truth. Any slide, caption or cue stamped at a wall-clock time can be placed exactly, with no guesswork about where the recording started.
Step 4
Hear it too
Turn the beep on and every second is marked on programme audio, so an audio-only path can be aligned the same way, and a dropped or doubled frame is a missing or doubled beep.
The clock is this machine's clock. Keep it NTP-synced; the page checks itself against the server and tells you when they disagree. Double-click the clock for fullscreen.