NDI® timecode, burn-in, MOV tracks and LTC: what is the difference? | Apex

Timecode visible in an NDI® picture is not necessarily usable editing data. Burn-in is drawn into pixels; NDI timecode travels in stream data; a timecode track belongs to a file; LTC is a signal that needs decoding. To choose between them, first ask which tool must read the reference and for what operation.

Distinguish four mechanisms

Burn-in helps with review conversations

A burnt-in reference remains visible during playback, as also described for the Final Cut Pro timecode generator. It is useful when requesting a correction or finding a moment with a client. It becomes part of the picture: keeping a clean master requires a separate output or recording.

Always associate that reference with a file. “00:03:12:08” alone can identify several takes. A note such as “interview-02.mov, Elapsed, 25 fps, 00:03:12:08” specifies the reference used; this is an example of a review convention.

NDI data and MOV data follow separate paths

The NDI SDK frame documentation describes separate timecode and timestamp fields in 100 ns units. Their presence in a stream does not guarantee that a receiver will display them or write them into its file. Check the recorder’s behaviour and that of the application that will read the media.

A MOV timecode track can supply an editing reference without any visible text. Conversely, a MOV with burn-in may have no dedicated timecode track. The player or timeline counter may also come from the project rather than the original file.

LTC requires a compatible workflow

LTC carries a time reference as a signal. The Tentacle SYNC E manual distinguishes a dedicated timecode input from recording the signal on an audio track. The latter requires decoding with a suitable tool. An ordinary audio track or an HH:MM:SS:FF display does not establish LTC support.

What Clock and Elapsed mean in Timecode Recorder

In the documented version 1.0, Clock builds the reference from the Mac’s time of day and Elapsed from the start of recording. The formatter does not calculate this text from incoming NDI source timecode. The camera can therefore carry a different reference from the one visible in the picture.

The overlay is present in the preview, H.264/AAC MOV and NDI and WebRTC monitoring outputs. The reviewed writer creates no dedicated timecode track, and the formatter provides neither LTC decoding nor drop-frame calculation. Choose this workflow for a visual reference; for conforming or synchronising multiple devices, verify a workflow explicitly designed for those operations.

Compare a file correctly in your editing application

1. Open the original MOV and note the frame rate, tracks and metadata reported in its properties.
2. Find an identifiable frame and note the burnt-in text separately from the application’s counter.
3. Check where the counter comes from: media timecode, playback position or sequence settings.
4. Keep the original for comparison. A new export may add metadata absent from the take.

Common mistake: inferring synchronisation from a readable clock

Two devices displaying similar times are not automatically synchronised to the frame. Define the required reference, frame rate and synchronisation method before capture. A visual check helps identify a moment; it does not replace that technical preparation.

NDI® is a registered trademark of Vizrt NDI AB.