imx8mm mini, v4l2 API is more difficult to use bandwidth if sensor resolution is lower

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imx8mm mini, v4l2 API is more difficult to use bandwidth if sensor resolution is lower

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bhgu
Contributor II

hello,

I'm testing v4l2 API on i.mx8mm mini evk board.

mipi-csi spec is 1200Mbps, 4lane.

when I set resoultion 1280x960, ideal max frame rate is 180fps

cal fps = date rate * lane / (cycle/pix * overhead * bit * width * height) = 1200Mx4/(2*1.35*8*1280*960)

but I'm using 75%, 135fps without no frame drop (tested getting 50,000 frame)

so if I set resolution 400x300, ideal max frame rate is 1851fps and expecting result is 75%, 1388fps

but some reason I should set 300fps because if I set more fps, frame drop happened.

Is this limitation of v4l2 API? (I guess because of copying frame to application..)

or do I have any things to try ?

help me

thank you 

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95 Views
Qmiller
NXP Employee
NXP Employee

Is this limitation of v4l2 API? (I guess because of copying frame to application..)

-->You are correct, copy every frame buffer also need time. 

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