Hi. I set up two USB cameras on the dragonboard 820C like as 1920/1080, H264 pixelformat. I can stream either of the two camera sucessfully. I used the v4l2-ctl to stream:
sudo v4l2-ctl -d /dev/video3 --stream-mmap=4
sudo v4l2-ctl -d /dev/video2 --stream-mmap=4
If I try to stream both cameras at the same time, then I get these error messages in the dmesg log:
[ 3061.336547] usb 3-1.2.2: Not enough bandwidth for new device state.
[ 3061.336583] usb 3-1.2.2: Not enough bandwidth for altsetting 11
These are the settings for each of the usb cameras:
root@linaro-alip:~# sudo v4l2-ctl --get-fmt-video -d /dev/video2
Format Video Capture:
Width/Height : 1920/1080
Pixel Format : ‘H264’ (H.264)
Field : None
Bytes per Line : 3840
Size Image : 4147200
Colorspace : sRGB
Transfer Function : Default (maps to sRGB)
YCbCr/HSV Encoding: Default (maps to ITU-R 601)
Quantization : Default (maps to Full Range)
Flags :
root@linaro-alip:~# sudo v4l2-ctl --get-fmt-video -d /dev/video3
Format Video Capture:
Width/Height : 1920/1080
Pixel Format : ‘H264’ (H.264)
Field : None
Bytes per Line : 3840
Size Image : 4147200
Colorspace : sRGB
Transfer Function : Default (maps to sRGB)
YCbCr/HSV Encoding: Default (maps to ITU-R 601)
Quantization : Default (maps to Full Range)
Flags :
root@linaro-alip:~#
Using a pixelformat of ‘MJPG’ causes the same errors as above. Can someone tell me what these error messages mean? Is it really a bandwidth issue with the compressed formats MJPG and H264?
Thanks,
Kim