We tried implementing such an error notification/limit into Videosync’s Console when Apple Silicon first launched, as at the time my M1 Macbook Pro would completely freeze and would require a hard reboot whenever I’d let Simpler max out the RAM, but couldn’t reproduce the same on my Intel Mac. It turned out it was quite hard to finetune when the limiter would take effect and the RAM pressure notification would appear, so it was pretty unreliable.
After some time passed, we weren’t able to reproduce the issue anymore, likely due to macOS updates, as macOS will now throw an error itself, saying the computer can’t continue to function unless the RAM hungry application is closed. So I think the crashing was just due to teething issues with M1 and Big Sur. Because of this we decided to drop implementing an error notification ourselves, and use the Start/End parameters to make it less likely excessive amounts of RAM are consumed. I think there is room for improvement for how this is communicated in the manual and in parameter info texts.
I wonder why the macOS error hasn’t happened for you though. May I ask what macOS version you are on?
Regarding understanding why so much RAM is needed for Simpler:
I’m assuming the file you’re using is encoded with h264, which would mean it’s a heavily compressed file. In order for Videosync to be able to instantly play the correct frame whenever you hit a MIDI note, the video has to be loaded in RAM uncompressed (this is the VTDecoderXPCService process you mentioned).
I personally actually have no idea how big such a file would be when it’s fully decompressed, or how to calculate that, so I asked ChatGPT 4 if it could make an estimation, and it could! I can’t verify its calculations, but given the assumed parameters (55 minutes, h264, 1080p, 24bit per pixel, 30fps), the estimated resulting file size would be 573.6 GB.
As ChatGPT nicely puts it:
This significantly larger size compared to the compressed file size (3.7 GB) illustrates the effectiveness of video compression methods like H.264 in reducing storage and bandwidth requirements.