huge latency difference between HDMI and SPI - Raspberry Pi Forums

hi everybody!

use 2 rpi 1b simple door viewer

first pi mounted @ tue door has camara attached , streams video mjpg-streamer clients (works great)
second pi mounted in living room , has tontec 3.5 inch screen (480x320) attached.

searched little bit around board , web simple python script.
first attempt using pygame works have huge latency. (approx. 5sec)
little test scrippt found on net using cv2 drops latency (approx. 3sec)

same scripts have (t<1sec) when executed on tv on hdmi

there known root cause why pygame slower vc2, , why output on dsi creates additional 3sec delay?

thx
mario

so, habe tested mjpg-streamer web page.

same issue:
when connected via hdmi video streamed should little delay betreten movement in front of tue cam compared image displayed.
when connected via dsi display 3-4sec delay produced

raspberrypi