Major sync problems on a project (offset + no corresponding sources)

5.62K viewsSoftwarebug offset software


I recently bought tentacle devices to facilitate sound taking and matching in postprod for a big project and I’ve been experiencing major issues of sync making my life very difficult. The worst is I have different scenarios depending on the days of shooting. Before exposing them, let me explain how the 2 devices were set on each of the 3 days:

  1. Synchronisation of the 2 tentacles with my macbook clock.
  2. 1 of the 2 devices was plugged into the time-in of our ZoomF4. Once the F4 was displaying the right time code, we unplugged it. in case the F4 was rebooted, we repeated that same operation.
  3. finally we plugged the tentacle of their respective camera (c100 and 5D)

When derush, here is what we observe:

1st day: takes on the C100 are all not matching with the sound (see screen Day1 C100). Takes on the 5D are matching at 10 to 20% despite the fact it seems the tentacle was TC at 25fps while the F4 was recording at 23.98(Day15D).

2nd day: in the morning, same scenario for both cams: all sync indicators are red (no corresponding sources). In the afternoon: there is a progressive offset happening on takes from both cams: first rushes on the sync map have a 5 sec delay and it increases up to 1:05 for the last takes… Any idea how to fix it? (Day2)

On day 3: by a miracle I couldn’t explain the C100 takes are perfectly sync by the app but the takes on the 5D were all off and I manage to identify a flat 29 sec delay that I managed to fix with an offset on timer. Thing I don’t get is that those 29 sec are not even matching the TC gap we can calculate between the Audio TC and File TC is 32 sec and 5 frames…

Anyway, this is a huge disapointment and I would really appreciate your help to correct these no corresponding sources and offset problems. But also, I really would like to figure the root cause(s) of these issues.

Thanks in advance

Answered question

The TC you want to synch must be at the same frame rate to match. 23.96≠25

Whether it be an audio TC or a metadata TC. Only exceptions: 25 works with 50fps and 30 works with 60 FPS.

Check the TC level of your Tentacle output.

Mic level for TC Audio on a Mic audio track.

Line Level for a Real TC input like Sound Device 833 or Sony pro camera

Bad level = TC unreadable = no corresponding

Answered question
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