Start video when Timecode stops

[David Sepulveda]

What it says at the title

I'm using a cue list based on LTC timecode

But when my timecode stops I need to start a video while the timecode is not runnin, then when timecode runs starts the triggered videos.

Any ideas?

Thank you!

[micpool]

As you are using LTC this is fairly straightforward as you can use the amplitude of the LTC

In the attached video QLab 4 is being used as the TC generator and is sending to QLab 5 on ch 16 of a virtual Bus.

In QLab 5 :
There is a text cue numbered "NOTC" that should play when there is no LTC input.

There is a group cue named TIMECODE MONITOR
The group contains:

A microphone cue numbered "TCMON" which routes the incoming timecode from virtual bus  16  to an unused audio bus (demo uses ch 10) 

A network cue with an OSC query which sets the notes of cue "LEV" to a value between 0 and 100, dependent on the live average level of ch 10  of  cue TCMON with a long duration at 10fps

A script cue with this script, which repeatedly looks at the notes of cue "LEV" and starts or stops  cue "NOTC" depending if the  notes of cue "LEV" are less or greater or equal  to 10, 10 times a second.

A Memo cue numbered "LEV"

tell application id "com.figure53.QLab.5" to tell front workspace

repeat

if notes of cue "LEV" < 10 then

start cue "NOTC"

else

stop cue "NOTC"

delay 0.1

end if

end repeat

end tell

Mic

[Rich Walsh]

Could you cut a few steps by constantly querying:

current timecode text of current cue list

This returns "" if there is no timecode, or a string like "1:00:01:23” if there is some.

Rich

On 28 Jul 2025, at 17:49, micpool <m...@micpool.com> wrote:

As you are using LTC this is fairly straightforward as you can use the amplitude of the LTC

In the attached video QLab 4 is being used as the TC generator and is sending to QLab 5 on ch 16 of a virtual Bus.

In QLab 5 :
There is a text cue numbered "NOTC" that should play when there is no LTC input.

There is a group cue named TIMECODE MONITOR
The group contains:

A microphone cue numbered "TCMON" which routes the incoming timecode from virtual bus  16  to an unused audio bus (demo uses ch 10) 

[micpool]

Yes, that's much simpler and works with MTC as well

The full script would be

tell application id "com.figure53.QLab.5" to tell front workspace

repeat

if current timecode text of current cue list is "" then

start cue "NOTC"

else

stop cue "NOTC"

end if

delay 0.1

end repeat

end tell

Screen recording and workspace  attached