What is LTC timecode?

LTC (Linear Timecode, SMPTE 12M) encodes an 80-bit hours:minutes:seconds:frames word into an audio signal, one word per video frame. Because it is just audio, it travels down any audio path — an XLR line, a console channel, a track in your playback rig — and any device that can decode it will lock to it.

What is the difference between drop-frame and non-drop timecode?

NTSC video runs at 29.97 fps, not 30, so a straight 30 fps count gains about 3.6 seconds per hour on the wall clock. Drop-frame fixes the label rather than the frames: it skips frame numbers 00 and 01 at the top of every minute except every tenth minute, so an hour of drop-frame timecode is 107,892 frames and matches real elapsed time. No frames of video or audio are lost — only the numbering changes.

What level should I send LTC at?

Aim for a healthy line level without clipping — around -6 dBFS out of a playback rig is a safe default. LTC is a square wave, so it is far more tolerant of level than it is of processing: keep it off any bus with EQ, compression, limiting, or lossy codecs, and never send it through a noise gate.

Can I use this timecode with QLab, Ableton Live, or a lighting console?

Yes. Download the WAV and play it from a dedicated output of your playback system, then patch that output to the timecode input of the device you want to chase — a lighting console, a media server, or a DAW set to sync to LTC. Make sure both ends are set to the same frame rate.

Free LTC Timecode Generator — SMPTE WAV & Batch Export

What this generates

LTC — linear timecode, defined by SMPTE 12M — is an 80-bit hours:minutes:seconds:frames word encoded as audio, one word per frame. It's biphase-mark encoded, which is a fancy way of saying the signal is a square wave that survives being flipped, attenuated, or run down whatever cable the venue has. Anything that can decode timecode — a lighting console, a media server, a DAW, a show-control rig — will chase it.

Everything here runs in your browser. Nothing is uploaded, and the file is built on your own machine, so you can use it on a locked-down show laptop with no internet.

Which frame rate should I pick?

The only rule that matters: every device in the chain has to agree. A console set to 30 fps chasing a 29.97 source will drift roughly a frame every 33 seconds, and you'll spend the afternoon blaming the cable.

Rate	Where you'll meet it
23.976	Film finished for NTSC video. Common in post, rare on a live stage.
24	True film rate. Occasionally used for theatrical playback.
25	PAL/EBU territory — the default across most of Europe, Australia and much of Asia.
29.97 NDF	NTSC video where the label doesn't have to match the wall clock.
29.97 DF	NTSC broadcast, where a running time on screen has to be honest.
30	Audio-only rigs and legacy gear in North America. A safe default for a show that answers to nobody else.

Drop-frame, in one paragraph

NTSC runs at 29.97 fps, not 30, so counting as if it were 30 gains about 3.6 seconds every hour against real time. Drop-frame corrects the numbering, not the frames: it skips the labels 00 and 01 at the top of every minute except every tenth minute. Nothing is lost — an hour of drop-frame timecode is 107,892 frames and lines up with a stopwatch. Drop-frame is conventionally written with a semicolon before the frames, like 01:00:00;02.

Using it on a show

Give it its own output. A dedicated channel out of your playback rig, patched straight to the timecode input of whatever is chasing.
Keep processing off it. No EQ, no compression, no limiting, and above all no noise gate. LTC is a square wave; processing rounds its edges and decoders start guessing.
Never send it through a lossy codec. Bluetooth, MP3, and most wireless systems will destroy it. Wired, uncompressed, or not at all.
Level it sanely. Around −6 dBFS is a good starting point. Loud enough to be unambiguous, with headroom to spare.
Start early. Give receivers a few seconds of timecode before the first cue — most need a couple of frames to lock, and a nervous console may want longer.
Mind the start time. Starting at 01:00:00:00 rather than zero is a long-standing habit: it leaves room for pre-roll ahead of the show without rolling past midnight.

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Batches

Set Number of files above one and you get a numbered .zip instead of a single WAV, with a manifest.txt listing every file and the timecode it covers. The files are named 01_, 02_ and so on — zero-padded to the length of the batch, so they sort correctly in a file browser and on a playback machine.

Timecode runs continuously across the set: each file picks up on the frame after the last one ended, so a long show cut into manageable chunks still lines up end to end. The file list above shows exactly what each one will cover before you download anything.

Durations snap to whole frames before rendering. Twenty seconds at 29.97 is 599.4 frames, and leaving that fraction in would make the second file start on the same frame number the first one ended on — a duplicated label, which is exactly the sort of thing that unpicks a show at 2am. Snapped, every file abuts the next exactly.

Questions

How long can these be?

Up to 60 minutes per file, and 240 minutes across a batch. A 60-minute WAV is already about 350 MB, though the zip is far smaller than that suggests — LTC is a square wave, so it compresses roughly fifty to a hundred times over.

Does this work offline?

Once the page has loaded, yes — the audio is generated locally. Worth loading it before you leave the hotel wifi.