video framerate with usb camera

[yibhan]

Hi guy,

I am asking why imx6qpsabresd build image output framerate with usb camera(logitech) is about 21 ~ 22 fps.

I am using gstreamer command like below:

1. 

# gst-launch-1.0 imxv4l2src device=/dev/video1 ! 'video/x-raw, format=(string)YUY2,width=640,height=480,framerate=30/1" ! autovideosink

the above framerate is about 21~ 22fps

2. 

# gst-launch-1.0 imxv4l2src device=/dev/video1 ! 'video/x-raw, format=(string)YUY2,width=640,height=480,framerate=15/1" ! autovideosink

the above framerate is also about 21~ 22fps, not 15 fps. where I check something ? 

My kernel version is 4.14.98_2.0.0_ga and cpu is imx6qp

Thanks

[igorpadykov]

Hi yibhan

one can try with "videorate" :

https://gstreamer.freedesktop.org/documentation/videorate/index.html?gi-language=c

https://stackoverflow.com/questions/20070625/how-to-control-the-frame-rate-in-a-gstreamer-pipeline

Best regards
igor

[yibhan]

Hi guys,

I have additional question on above subject. I have setup framerate 30/1 but, actually real framerate is 21 ~ 22fps, it seems to be mean for me imx6qp perform framerate is 21 ~ 22 fps even though settting is 30/1 or there is no enough information to catch up performance.

Can you follow camera performance ?

[yibhan]

for your infomation,

I have tried "gst-inspect-1.0 imxv4l2src" and result is like below:

: framerate = {(fraction) 30/1, (fraction) 15/1}

Does it mean 15/1 framerate is available?