FPS is defined as 'Frames per second'.
On software compression bt878a cards (PV- series and Euresys cards) each 'chip' is 30FPS

The human eye can 'see' around 24FPS. We list capture cards at their total FPS for all ports on the device. Take for example the PV-149, which is a 120FPS 4 port capture card. By dividing the total FPS of the card (120) by the total ports (4) each port on the card can record at 30FPS.

Now let's get a bit more complex. Take for example the PV-155, which is a 120FPS 16 port capture card.

Note: The following does not relate to our hardware compression cards since there's no switching involved. These cards can receive 7.5FPS @ 120FPS, 15FPS @ 240FPS, or 30FPS @ 480FPS.

Dividing the total FPS (120) by the total ports (16) would you give 7.5FPS. However this isn't necessarily what you would receive from your application. Since the card has to share the input with 3 other devices the FPS drops, so for 16 ports @ 120FPS you should expect to receive 3-5FPS.