What exactly difference between Video Capture rate, Frame Rate and Refresh Rate in video processing ? Can we change FPS of CPU graphics ie. rate of Frame per second or not? if yes then how ?
Before explaining what's Video Capture rate, let's read what's Refresh Rate and Frame Rate.
Refresh rate represents how many times the actual TV, video display, or projected screen image is completely reconstructed every second. The idea is that the more times the screen is "refreshed" every second, the smoother the image is in terms of motion rendering and flicker reduction.
In other words, the image looks better the faster the screen can refresh itself. Refresh rates of televisions and other types of video displayed are measured in "Hz" (Hertz). For example, a television with a 60hz refresh rate represents a complete reconstruction of the screen image 60 times every second.
As a result, this also means that each video frame (in a 30 frame per second signal) is repeated twice every 60th of a second. By looking at the math, one can easily figure out how other frame rates relate to other refresh rates.
Remember those cool little flip books where a pad of paper had an image on every page, and when you flipped through the pages quickly, the image would appear to animate and move? This is essentially how video works. Whether digital or old-school film, video is a series of still images that, when viewed in order at a certain speed, give the appearance of motion.
Frame rate is the speed at which those images are shown, or how fast you “flip” through the book and it’s usually expressed as “frames per second,” or FPS. Each image represents a frame, so if a video is captured and played back at 24fps, that means each second of video shows 24 distinct still images. The speed at which they’re shown tricks your brain into perceiving smooth motion.
Video Capture rate:
Video Capture rate is just on how many FPS (Frames Per Second) the video will be captured/recorded. As we read above, with more FPS the video stay smoother, and with less FPS, it stays more "laggy".
Now let's talk about
GPU Frame rate:
FPS can easily change while you're using the computer. Heavy tasks like playing games can decrease your Frame Rate, while just using your Browser it's almost not going to change your Frame Rate (FPS).
Higher resolutions decrease Frame Rate (FPS), since the image to load is heavier.
There are many ways of increasing your FPS, I suggest this website.
How is the frame capture rate and Refresh rate depends upon each other?
Remember that FPS is how many frames your computer is producing or drawing, while the refresh rate is how many times the monitor is refreshing the image on the screen. The refresh rate (Hz) of your monitor does not affect the frame rate (FPS) your GPU will be outputting. However, if your FPS is higher than your refresh rate, your display will not be able to display all of the frames your computer is producing, so although the refresh rate doesn’t technically limit the frame rate, it does effectively set a cap.
If I have 60Hz monitor then how much fps Video Capture card needed so that I don't want to loose any frame while capturing through video?
As we read above, the refresh rate (Hz) doesn't really matter if we're speaking about frame rate (FPS), so just record your video at 60 FPS and it's all set.
Sources: https://www.lifewire.com/video-frame-vs-screen-refresh-rate-1847855, https://www.techsmith.com/blog/frame-rate-beginners-guide/, https://www.avadirect.com/blog/frame-rate-fps-vs-hz-refresh-rate/ and my knowledge.
I hope this satisfies your doubts.