SMPTE Timecode FAQ

What is SMPTE timecode?

SMPTE timecode is a standard for labelling frames of video or film, developed and defined by the Society of Motion Picture and Television Engineers, used for syncing film and video across platforms and programs. The timing of video is measured in frames per second, and three different units of time are useful when scoring music to film: Samples (Audio), Beat Time (Music) and Frames/SMPTE (Video).

How can I view timecode in Ableton Live?

By default, Live's Arrangement View timeline displays time (minutes:seconds:milliseconds), but you can also set it to display frames per second. To change the timeline format, right-click the Time Ruler and select an fps standard from the context menu: 

Can I use SMPTE timecode to sync audio and video in Live?

Live does not sync to incoming SMPTE timecode. Live also does not generate SMPTE natively. To send an SMPTE timecode out of Live, there are two available workarounds:

LTC SMPTE audio file

  1. Generate an LTC SMPTE audio file with a designated frame rate and start time, using the free third-party web app El-Tee-See Two: SMPTE LTC .wav file generator.
  2. Load the LTC SMPTE file into an audio track in Live's Arrangement View.
  3. In Audio Clip View, turn off warp for the clip.
  4. Route the track's audio to the video host application.
    - If the video is on a different computer, use a dedicated output on your audio interface to route audio from Live to the other machine. Learn more in the guide Setting up an Audio Interface and the Live manual section Routing and I/O.
    - To sync with another application on the the same computer, follow the instructions in this guide: How to route audio between applications .


LTC SMPTE audio signal via Max for Live (macOS only)

The free Max For Live device Showsync outputs an LTC SMPTE audio signal with the current playback position of the active clip, taking warp markers and tempo changes into account to guarantee a time sync that is always aligned with the clip playback.

This method is supported on macOS in Ableton Live Suite, or with Max for Live as an add-on to Live Standard. Learn more about Live Suite features

How is SMPTE timecode derived?

SMPTE timecode appears as hour:minute:second:frame (for example, one hour would be written as 01:00:00:00). The frame rate is derived directly from the data of the recorded medium: in other words, the frame rate is inherent to the media, and can differ for film vs. digital, video vs. audio, and color vs. black and white.

SMTPE Timecode is linear, which is why it's commonly called LTC (Linear timecode). This means that it doesn't change speed. So, for example 00.45.00.01 is always 45 minutes, 0 seconds, frame 1.

With audio, instead of frames being the lowest division, it's samples. So audio is HH:MM:SS:Samples (Hours, Minutes, Seconds, Samples)

What is an example application of SMPTE?

The classic example would be an actual spool of film with SMPTE timecode recorded as an audio signal on its audio track. For example a VHS tape of a movie with SMPTE timecode recorded on one of the audio channels. The SMPTE signal is then sent to a tape machine, playback system or DAW which "chases" the SMPTE signal to playback audio in time with the film. The movie starts at 00.00.00.00 SMPTE time and your music also starts at 00.00.00.00 in beat time.

How can I sync audio with a different start time than the video?

In some cases the start of the video and the start of the music are aligned, such as when scoring one scene in a film.

For example, take a scene that starts at 00.45.00.01 SMPTE time (45 minutes, 0 seconds, frame 1). For beat 00.00.00.00 to fall at 00.45.00.01 SMPTE time, you need to offset SMPTE time and Beat time from each other to get correct playback. Programs that support SMPTE timing offer ways to adjust the relationship between beat time and SMPTE time so that this works.

If the director edits another scene in the film, then the timing of your scene is still the same but now your scene starts at 00.43.03.15 (45 minutes, 3 seconds, frame 15). So you need to be able to adjust the relationship between SMPTE time and Beat Time accordingly to keep everything in sync. 

Ableton offers these in-depth help and learning resources: