Skip to content
English
Contact us
  • There are no suggestions because the search field is empty.

Achieving Frame-Accurate Sync Between Display Servers

Achieving Frame-Accurate Sync Between Display Servers Overview

When running a multi-server WATCHOUT setup, all display servers must be synchronized to ensure seamless video playback across outputs. WATCHOUT provides multiple synchronization methods.

Sync Methods

1. NTP-Based Sync (Default)

WATCHOUT uses NTP (Network Time Protocol) for timeline synchronization by default.

  • The Director machine acts as the NTP reference.

  • All Runners (display servers) sync their timeline clocks to the Director.

  • This provides millisecond-level accuracy, sufficient for most setups.

Requirements:

  • All machines on the same network

  • Stable network connection (wired, not WiFi)

2. Hardware Genlock (Quadro Sync II)

For frame-accurate sync (required for seamless edge blending):

  • Use NVIDIA Quadro Sync II cards with compatible GPUs (e.g. NVIDIA A6000, RTX A-series)

  • Configure sync groups in WATCHOUT to define which servers sync together

  • One server acts as the sync source; others follow

WATCHPAX 62/64: These units have BNC sync connectors. Connect to an external sync generator (e.g. Blackmagic Sync Generator) or daisy-chain between units.

3. NVIDIA Mosaic Mode

For outputs spanning multiple display ports on the same GPU:

  • Configure Mosaic in NVIDIA Control Panel before starting WATCHOUT

  • Combined with Quadro Sync II for multi-server setups

Setup Steps (WATCHPAX 62/64)

With the R30 image and the WATCHPAX Config Tool:

  • Open the WATCHPAX Config tool

  • Configure Mosaic/Sync/EDID settings

  • Select which unit is the sync source and which units follow

  • No external sync generator is required for basic 2-unit sync — one unit drives the other

See the WATCHPAX 64 User's Guide for detailed Config Tool instructions.

Troubleshooting

Stuttering/Choppy Playback Across Servers

  • Check NTP: In Producer, look at the Nodes window. Verify "NTP Diff" is near zero for all runners.

  • Check sync groups: Ensure all servers in a sync group have stable connections (7.7.1 fixed a sync group bug from 7.7.0).

  • Check cables: A faulty BNC cable or network cable can cause intermittent sync drops.

  • Check hardware: A failing WATCHPAX unit can cause the entire sync group to stutter when it drops in and out.

NTP Shows "N/A"

  • The Runner service may not be running — check that the display software is active.

  • Restart the Director/Manager after any system time changes.

  • Do NOT change the system clock during playback.

Sync Groups Not Working (7.7.0)

This was a known bug in WATCHOUT 7.7.0. Update to 7.7.1 which contains the fix. Confirmed working with NVIDIA A6000 + Quadro Sync II (firmware 306, driver 582.16).

Best Practices

  • Use wired Gigabit Ethernet for all sync communication

  • Set BIOS clocks on all machines to the correct time

  • Avoid changing system time during operation

  • If using NTP sync on an isolated network (no internet), the Director's clock is the reference — ensure it's accurate

  • For critical installations, use hardware genlock (Quadro Sync II) for frame-level accuracy

Last updated: 30 March 2026 · Dataton Support