What is your audio routing? if mic plugged into NDI camera? or do you have separate audio and video cables/connections to OBS PC (which is normal). If the latter, you need to manually sync audio to video
My NDI camera (Panasonic) and their Virtual USB driver, is quick enough, that I don't need to delay audio to have adequate sync. but your mileage may vary. It is common for video to take longer to process (compress on camera, transmit over Ethernet, decompress on PC, then process into OBS). NDI HX compresses more to use less bandwidth, which means it takes slightly more time to de-compress. And different vendors have different quality/maturity of camera codec and drivers, which can have latency impact. Some NDI cameras are rather slow, others less so.
Which i7?
Laptops, optimized for battery life, sometimes are NOT up to the task of the very computationally demanding task of real-time video encoding.
I recommend monitoring hardware resource (CPU, GPU, RAM, etc) utilization [for ex. using Task manager’s Performance tab and/or Resource Monitor] to see if your system is being maxed out with your settings
Though, the common scenario is for audio to be processed faster than video, and a need to delay audio (and that ability is built into OBS). But your scenario indicates giving your PC more to do (crop video, and composite 2 video sources - camera and PPTx) and then sync being ok...
So.. depends on your setup and settings
Per pinned post in this forum
OBS Studio creates a log file each time you run it which contains very useful diagnostic information. Without a log file, it's much harder for any support volunteers to figure out problems and your post may be ignored. To upload a log file, go to the Help menu > Log Files > Upload Last Log...
obsproject.com
