The output of the DisplayPort 2.1 RX Subsystem is either a quad pixel interface (4PPC) or an octa pixel interface (8PPC) as per the selected option for Pixels Per Clock (PPC) on output in subsystem's configuration screen.
In case of 4PPC, valid pixels are available on pixel 0, pixel 1, pixel 2 and pixel 3 where as in the case of 8PPC, valid pixels are available from pixel 0 to pixel 7.
The data width of the AXI4-Stream interface depends on different core parameters.
Interface Width = Pixel Width ×
PPC
For example, if the system is generated with MAX_BPC equal to 16 with 8PPC, the data width of the AXI4-Stream interface is 16 x 8 x 3, which equals 384.