You say it skips, as in recordings to the card ? That can be a trait of the wrong SD card for starters. What are you using ? Remember when no NVR is present the cam is having to handle everything with its only option to offload being its RAM buffer and SD card storage. You mention the skips are random, anything common to them though, high speed traffic, night only etc ? How is the camera's FOV setup, are you so tight you'll capture 1-2 frames before target has left screen or is this a wider shot with ability for the cam to target and capture over a period of frames ?
Definitely tell us the card you are using, remember not all SD cards are created equal. Only a few really work well with surveillance cams, Samsung Pro Endurance for example are great for these cams but others that may seem to offer the benefit of faster write speeds are not.
As
@bigredfish and others point out neither IVS or MD are 100% however they allow you to dial in your capture requirements to ensure that very few 'real' triggers are missed. AI cams take this one step further with object filtering ensuring that all the stuff you're not interested in (leaves etc) are not captured while the important ones are. Definitely take time to tweak the image and the triggers, its very necessary and will take your captures from mediocre or even missed events to crisp, usable footage.
Now onto the NVR, remember what I mentioned above about offload, when doing this all on cam you are taxing the cam (this is before you also try and playback while its potentially actively still monitoring new events). Connecting / offloading to an NVR allows it to do the heavy lifting and any related processing from the stream provided by the cam itself so please don't think if you see a missed frame here or there, or missed event on cam that the NVR will do the same. Thats not to say that newer cams don't have better SOC's increased RAM and ROM that can help process quicker but being able to offload to a standalone NVR or NVR platform (BI) is always a step up. Like
@bigredfish I've used and installed many Dahua NVR's and currently have a 5216 in rotation running 4.0. Great NVR, very capable even when I hit it with a number of AI cams for ANPR, Face Detection & Recognition, Object Filtering etc, doesn't miss a beat.
On the cam front, unless I missed it (which I may have) also list which ones you purchased. I certainly wouldn't lower FPS, remove sub streams and generally downgrade your captures yet. Using H264H thats not a problem but hold off all the other changes for now.
HTH
