Video Synchronisation

MultiMon’s sync model is deliberately simple, because a simple model is one you can predict under show conditions.

One master clock

There is one master clock, and everything on screen is drawn against it. There is no master source and no slave sources; no source is chasing another.

Nearest-frame selection

At each moment, every source shows the nearest frame at or before master time. If a source is running behind, frames are dropped to catch up; if it is ahead or its frame rate is lower, the current frame is repeated.

What MultiMon deliberately does not do:

• No speed adjustment. Playback is never sped up or slowed down to close a gap.
• No seek correction. Sources are not re-seeked to chase the clock.

The result is that a frame you see is always a real frame of the source, and the whole wall agrees on what time it is.

Span and Split are already in sync

Span and Split both run from a single source, so there is nothing to synchronise between outputs — the screens are showing parts of the same picture from the same decode.

Individual mode and the Sync checkbox

Individual mode plays a different source on each monitor. Those sources are independent by default, each on its own clock.

Tick the checkbox labelled Sync (frame-lock same-length clips) to run them all off the shared master clock, so they start, pause and resume together and each shows its nearest frame at or before master time.

The label is also the condition. Frame-lock holds only for clips of equal duration: MultiMon does not stretch, loop-align or re-time anything, so clips of different lengths put on one clock will simply run out at different moments.

Leave Sync off when the sources are meant to be unrelated — separate loops that need not line up.

Hap mode

Hap mode plays a different HAP clip on each monitor and puts all of them on the one shared clock — there is no checkbox, because the shared clock is the point of the mode. HAP frames are compressed textures the GPU consumes directly, so the decode is fast and even enough to hold several streams tightly frame-synced.

Hap or Individual with Sync?

	Individual + Sync	Hap
Clip format	Anything MultiMon plays — H.264, HEVC or a mix	HAP files only
Decode path	Media Foundation, even for a .mov that holds HAP	The from-scratch HAP path
Clock	Shared, when the checkbox is ticked	Shared, always
Use it when	Your clips are ordinary delivery files	Every clip is HAP and the wall has to stay tight

Both still need clips of equal duration to stay frame-locked.

Audio

Audio is clocked to the same master timeline that drives the video, so sound stays locked to picture across the wall. See Audio mixer.