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xenpac / sun4i_csi

new OV5640 Camera Driver CSI A20 Lemaker BPI Banana Pi, Linux Sunxi Kernel 3.4.xx
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SXGA (1280*960) with subsampling #2

Open JPMJPM opened 5 years ago

JPMJPM commented 5 years ago

Hi, this not an issue, it is only a question.

Is it possible to get SXGA with subsampling in order to reach more FPS than scaling solution ?.

Regards.

xenpac commented 5 years ago

see file ov5640.c, there is a docu at the very bottom. search for "Docu on Video Timing and output sizes:", read. you first need to crob your wanted picture size from the sensor = +1 section. then enable subsampling 2x2, which halfs the datasize. (note that omnivision does not provide exact docu!!, so this is all from experience) to get a stable picture you have to experiment with the timing. search "calculation of HTS VTS".

in short, to get fast fps you need to just take a portion of the sensor (crob) and adjust the timing.

look at file gc0308.c using the "zoom" function, to achive fasted fps of ??120 fps possible.

note: all these c-files are for the ov5640 sensor!! i just used different names to compile in the source tree, and be able to switch "devices" (modprobe) on the fly to experiment.

also note that the bananapi has limits on what datarate it can handle on CSI!!

xenpac commented 5 years ago

another note for those armbian kernel 4.xx users, the new kernel does not support the CSI interface to be used with the camera!! As it has device tree implementation, and that has not yet covered the CSI parallel interface. If thatever gets implemented, it will need to completely redesign the camera driver.

JPMJPM commented 5 years ago

Thanks, I will try it.