UPDATE and a humble ask for someone from the BlackMagic team to help out.
I hired a friend who is a sysadmin, to see if he can solve this puzzle and here is what we found:
- opening one of the drone clips h.265 .mov 29.98fps directly in VLC player -> crashed the app
- changing the Output in VLC Preferences from "Automatic" to "Direct3D9" -> the clip played beautifully
- still in VLC Preferences, we then tried Direct3D11 -> the app crashed immediately
Obviously, choice of system engine/encoder (please forgive my lack of proper terminology) DirectX or whichever, plays a role here. In Resolve it is not possible to choose, except for the GPU Processing mode. Since, unfortunately, I am on AMD (Asus Rog Strix Vega64), I am stuck with auto or Open CL, no CUDA.
The Resolve weirdness:I realised that editing with h.265 is a bad practice and a
no go so I created a DNxHR SQ proxy, lowered the playback resolution to 1/4 -> stuttering and bad frame-seek issues.
I then fully transcoded the clip to DNxHR 444 12bit, imported into project, tried this huge quality clip in both native 29.98 AND projects native 24fps timelines -> both played beautifully, with minimal stuttering. Even 4K played nice.
Is it possible that Resolve is changing these Direct3D's behind the scenes, depending on the output quality, codec or something?
Please please help, I cannot be transcoding everything to 444 codecs as storage is already an issue.
Many thanks!