Avid Media Composer does not generate MIDI Timecode (MTC). For Playback to chase the Avid timeline, you:

1. Create an LTC audio file (WAV) that matches the sequence start timecode and frame rate.
2. Edit that file onto a dedicated audio track in the Media Composer sequence.
3. Send that track to a virtual audio device such as BlackHole.
4. Use the GSi SMPTE Tool to convert the incoming LTC to MTC.
5. Set Remoto Playback to chase MTC.

You can then add timecoded markers in Playback, export them as a .csv file, and place them on the Media Composer timeline. This does require converting the resulting  .csv  to either a .txt or .xml file. 

For NDI or Blackmagic UltraStudio video and audio into Playback, see Using Avid Media Composer with Remoto Playback. For marker export formats, see How to Work With Timecoded Markers.

Before you start

• macOS or Windows (GSi SMPTE Tool install steps below are for Mac)
• Avid Media Composer
• Remoto Playback Desktop
• An LTC WAV from EL TEE SEE (LTC Generator)
• GSi SMPTE Tool
• A multi-channel virtual audio device such as BlackHole 16ch
• Sequence frame rate and start timecode already set

Open Playback Desktop before you configure the GSi SMPTE Tool. The MIDI destination Remoto_out appears only after Playback is running.

Keep program (session) audio off the LTC channel pair so guests do not hear the LTC tone.

Step 1. Download and install the GSi SMPTE Tool

1. Download GSi SMPTE Tool v1.0.0 from Genuine Soundware: https://www.genuinesoundware.com/?a=page&p=SMPTE_Tool
2. Choose GSi Download Center for macOS.
3. Open the installer. At the bottom, turn on Show Extra.
4. From the dropdown, select SMPTE Tool - Mac v.1.0.0.
5. Download the tool and follow the on-screen installer.

Step 2. Confirm sequence start timecode and frame rate in Media Composer

1. Load the sequence you will stream.
2. Confirm the sequence frame rate (for example 23.976, 24, or 25 fps).
3. Set or confirm starting timecode:
   • Timeline Fast Menu (hamburger) → Sequence → Starting Timecode, or
   • Right-click the sequence in the bin and set start timecode there.
4. Write down the start timecode and duration of the sequence (or longer than you expect to play). The LTC file must match both.

Media Composer, the LTC file, the GSi SMPTE Tool, and Playback must all use the same frame rate.

Step 3. Generate an LTC audio file (EL TEE SEE)

Media Composer will play this file as audio. GSi SMPTE Tool will decode that audio as LTC.

1. Open https://elteesee.pehrhovey.net/ (EL TEE SEE timecode generator).
2. Open the LTC generator (Linear Timecode / SMPTE-EBU, WAV export).
3. Set:
   • Frame rate to the Media Composer sequence frame rate
   • Start timecode to the sequence starting timecode (for example 01:00:00:00)
   • Duration at least as long as the sequence (longer is fine)
   • Sample rate 48 kHz if the generator offers a sample-rate option
4. Export or download the file as a WAV.

The WAV is a continuous LTC tone. When it plays from the correct position on the Avid timeline, the decoded timecode matches the sequence.

Step 4. Add the LTC file to the Avid sequence

1. In Media Composer, import the WAV into a bin (File → Import, or drag the file into the bin).
2. Open the sequence in the Timeline.
3. Add a dedicated audio track (for example A8) and name it LTC if you use track names.
4. Edit the LTC clip onto that track so the head of the clip lines up with the sequence start.
5. Confirm the clip covers the full range you will play. If the sequence is longer than the WAV, generate a longer file and replace the clip.
6. Do not time-compress, reverse, or add AudioSuite processing that would change the LTC waveform.

If the sequence start is 01:00:00:00 and the WAV was generated from 01:00:00:00, placing the clip at the sequence head keeps LTC in lock with the timeline.

Step 5. Route the LTC track to BlackHole (or any other virtual audio device)

GSi SMPTE Tool cannot see Media Composer directly. It listens to a virtual audio device. BlackHole 16ch is the usual choice on macOS.

1. Install BlackHole (16ch recommended) if it is not already installed.
2. In Media Composer, open Audio Project Settings.
3. Set sample rate to 48 kHz.
4. Set the audio Hardware output to BlackHole 16ch.
   Media Composer can use only one audio output device. If you still need headphones or an interface, create a Multi-Output Device or Aggregate Device in Audio MIDI Setup that includes BlackHole, then select that device in Audio Project Settings.
5. Open the Audio Mixer.
6. Route the LTC track to a dedicated BlackHole pair that is not used for program audio — for example outputs 15–16 (or a single mono output if you use Direct Out).
7. Keep program mix on a different pair (for example 1–2), or send program audio via NDI Desktop Audio / embedded SDI as described in Using Avid Media Composer with Remoto Playback.
8. Do not mute the LTC track. It must play with the timeline. Do not include the LTC channels in the mix guests hear.

Play the sequence and confirm in macOS (for example Audio MIDI Setup or a meter on BlackHole) that the LTC track is reaching BlackHole. You should hear a steady LTC tone only on the LTC channels, not in the guest mix.

Step 6. Configure the GSi SMPTE Tool to receive BlackHole LTC and send MTC

1. Launch the GSi SMPTE Tool.
2. On the Device Settings tab:
   • Output: << none >>
   • Input: BlackHole 16ch
   • Active output channels: leave as is
   • Active input channels: the same pair Media Composer uses for LTC (for example 15–16)
   • Sample rate: 48k
   • Audio buffer size: leave as is
   • MIDI Output: Remoto_out (visible only after Playback Desktop is open)
3. On the GSi SMPTE Tool tab:
   • MTC Send Type: set Mode to QF (Quarter Frame)
   • Generator Frame Rate: match the Media Composer sequence and the LTC WAV
   • Click Generate
4. Play the sequence in Media Composer. The GSi SMPTE Tool should display running LTC (decoded from BlackHole) and transmit synchronized MTC to Playback.

Step 7. Configure Remoto Playback to chase MTC

1. In Remoto Playback, open Session Settings.
2. Set video (and program audio) as you normally do for Media Composer — NDI or Blackmagic UltraStudio. See Using Avid Media Composer with Remoto Playback.
3. If Playback also takes audio from BlackHole, set Audio Input Device to BlackHole 16ch and Audio Input Source to the program pair (for example 1–2), not the LTC pair.
4. Under Timecoded Markers (sync input), select Remoto MIDI Device Input Port.
5. Playback now chases MTC from the GSi SMPTE Tool.
6. In Session Settings, open Preview. With the sequence playing in Media Composer, the Timecode readout in Preview should follow Media Composer transport.

You can now use Playback’s timecoded markers. Export markers as .csv before the session is finished, then convert to either a .txt or .xml file and import them onto the Media Composer timeline (locators). See How to Work With Timecoded Markers.

Notes

• Leave the GSi SMPTE Tool open while you stream. Closing it stops timecode.
• The LTC WAV, Media Composer, GSi SMPTE Tool, and Playback must use the same frame rate and the same start timecode alignment.
• If GSi shows no LTC, confirm the clip is on the timeline, the track is not muted, Hardware output includes BlackHole, and GSi input channels match the LTC pair.
• If Playback does not show timecode, confirm QF mode is on, MIDI Output is Remoto_out, and Playback was launched before GSi.
• Adjust level in the GSi SMPTE Tool if LTC is too hot or too quiet to decode.
• Do not send the LTC tone to guests.

Related articles

• Using Avid Media Composer with Remoto Playback
• How to Work With Timecoded Markers