[LST]

hi,

sorry for my late reply... I try some stuffs...

As a reminder, here is my initial workflow :
ProTools 2021.12 / macOS Catalina
Video played on the NEXIS, ProTools session in LOCAL disk.
The MTRX and the Decklink BlackMagic are powered by the MUTEC “SD/HD Video Out” outputs (PAL signal, Blackburst).
The DADman is well locked in video ref, and the ProTools video track gives access to the output settings of the BM card: "Locked PAL (SD)"
The video provided by the client is a ProRes 422, 25fps (clock and ProTools project at 25fps as well).

TEST 1: Disable GPU in ProTools preferences ❌
TEST 2: Deactivate the compensation delay ❌
TEST 3: Increase cache size from 40 to 56GB ❌
TEST 4: Deleting ProTools preferences ❌
TEST 5: Switch the ProTools video track from Full Quality to Draft ❌
TEST 6: Video transcoding of the client's video in ProRes422 HQ ❌
TEST 7: Video transcoding of the client's video in ProRes422 proxy ❌
TEST 8: Video transcoding of the client's video in ProRes422 i ❌
TEST 9: Video transcoding of the client's video in DNxHQ ❌ (3 desynchronizations over 1h50 of film instead of 8 to 12).
TEST 10: Video transcoding of the customer's video in DNx36 ❌
TEST 11: Switch the clock internally (mutec off, DADman in internal source sync) ❌
TEST 12: Connect the MTRX and the BM to the MUTEC in Word Clock and change the source sync of the DADman to word clock ❌
TEST 13: Go back to Decklink BM driver 11.7 (the higher version is not compatible with macOS Catalina) ❌
TEST 14: Replacement of the MUTEC by an AVID SYNC X in video ref and in word clock. DADman/ProTools/Decklink locked in HD ❌
TEST 15: Instead of playing the video on the NEXIS, play it on another external SSD ❌
TEST 16: Opening another project with video exported directly from DaVinci Resolve Studio in DNxHD36, then imported into ProTools ❌ (1 desync on a 1h20 film)
TEST 17: Exchange of BM card with that of the calibration room (BM Decklink 4K Extreme 12G) ❌
TEST 18: Playing video from an external drive (LaCie Big6 Thunderbolt 3) connected directly to the MacPro ❌
TEST 19: Opening sound editing sessions on a Mac mini and in the mixer's home studio ✅

I had several technicians/mixers/trainers on the phone who advised me to stop with ProRes anyway and to work only in native AVID format, and to favor work on two discs in LOCAL (1 for the video and 1 for the ProTools session), but that doesn't solve the problem.


Findings:
- The clock problem would be surprising because the SYNC X don't fix the problem.
- It is not a session problem because it is transferred to another project and it is read without worries on a Mac mini.
- This is not a reading problem on the Nexis, because the problem appears with reading on an external disk in Thunderbolt 3.
- This is not a codec problem but DNxHD still causes less synchronization than Apple ProRes.
- It is not video card problem because the Extreme 12G postpones the problem. Is an AJA card a solution?