I was wondering if I use SSD instead of HDD in my NVR would it will give me more crispy video footage as writing speed increases in SSD. Asking this because I observe the live preview in my NVR is much more sharper than the recorded preview from storage. The camera setting is highest (Video bitrate 8mbps, 20 fps ,2560 × 1440 ). Camera model :- ds-2cd1043g0
Nope. Your issue is your camera is from the value series, so they shove too many MP on a sensor designed for less MP. That is the reason for crappy footage.
Best practice is to simply but video on the HDD rated for surveillance cameras.
SSDs are not really designed for the continuous writing on. Sure people have used enterprise ones and can get many years out of it, but if yours is a cheap consumer grade so it may not be able to keep up, but you will probably kill the SSD in a year or less like this person has twice:
Hdd are enough to read/write at 200MB/s (so 1600 mbit/s) - much higher that any normal NVR is capable.
If yours stored footage is not „sharp” comparing to live view - it means you configured NVR to store secondary feed (low resolution one) and simply you watch that. Switch to main stream and this will solve problem
SSDs for surveillance exist are are primarily designed for mobile system (e.g. in a bus).
A standard CCTV rated HDD is still the cheapest and most suited to the job.
If you want some better performance, buy a CCTV HDD with more cache.
This sounds like you are recording the substream and not the mainstream video.
Mainstream video is the full resolution of the camera. Substream is a lower resolution (e.g. D1).
Substream's now days only have a purpose for live viewing when a system is under powered to load the mainstream.