Timecode display & frame rate

The timecode display is the primary reference for the current playback position. It shows the exact SMPTE address being broadcast on every output protocol, in real time.

Reading the display

The large display shows SMPTE timecode in the standard HH:MM:SS:FF format:

• HH — hours (00–23)
• MM — minutes (00–59)
• SS — seconds (00–59)
• FF — frames (00 to the frame rate minus one)

The detected or configured frame rate is shown next to the display. Remaining time for the current song appears in the transport area below.

Supported frame rates

• 24 fps — film standard; frames 00–23
• 25 fps — PAL video standard; frames 00–24
• 29.97 fps Drop-Frame (DF) — NTSC broadcast; skips frame numbers 00 and 01 on certain minutes to stay aligned with wall-clock time
• 30 fps Non-Drop-Frame (NDF) — studio and post-production; frames 00–29; simpler math but drifts slightly relative to real-time over long durations

Drop-Frame vs Non-Drop-Frame

29.97 fps video runs slightly slower than exactly 30 fps. Over an hour, this adds up to approximately 3.6 seconds of drift between the timecode count and actual clock time. Drop-Frame timecode compensates by periodically skipping two frame numbers (not actual video frames) — frames 00 and 01 are skipped on every minute except every tenth minute.

The result: a one-hour program in 29.97 DF timecode runs from 00:00:00:00 to 00:59:59:29 and corresponds exactly to one hour of real time. Non-Drop-Frame does not apply this correction.

Auto-detection and Force FPS

When an audio file is loaded, LTCast reads the embedded LTC signal and identifies the frame rate automatically. The detected rate appears in the FPS indicator.

If the auto-detection is incorrect — for example, because the LTC level is low or the file has an unusual encoding — use the Force FPS selector to override the detected rate. LTCast will decode all LTC using the forced rate.

• A yellow warning badge appears when Force FPS is active and differs from the auto-detected rate
• Set Force FPS back to Auto to restore auto-detection

FPS mismatch warning

If the LTC signal in the audio file encodes a different frame rate than what LTCast is configured to decode, the timecode values will be wrong. The FPS mismatch badge is a reminder to check this setting before the show. Always verify the frame rate matches your receiving devices.