Out-of-sync multi-channel video shows up in two forms. Identify which one you have first.

• Different timestamps: each image displays its own time, meaning the clocks were never unified. Fix it with a common NTP source, or have the recorder push time to every channel.
• Different event timing: the same event appears at noticeably different moments on different channels, which is latency skew. Common causes include buffering from excessive bitrate, switch port congestion, or some channels running over a wireless bridge.
• Decoder buffering: clients enlarge buffers to avoid corrupted frames, and different buffer policies per channel create visible skew. Equalise buffer times or reduce per-channel resolution.

A sensible order is: unify the clocks, then review per-channel bitrate and network load, and finally check for wireless segments or excessive switch hops. Where strict synchronisation is mandatory — for example multi-angle evidence capture — choose models and platforms that support a common time base and synchronised playback.