Under an embedded Linux environment, and with Python, I am trying to get a video feed from my USB Camera,
Using OpenCV "default" implementation works perfectly :
video = cv2.VideoCapture(cv2.CAP_V4L2)
But because I need to customize the pipeline, I am trying to use directly the gstreamer pipeline, but I get warnings and the pipeline is not created.
I have tried various pipelines like :
pipeline="v4l2src device=/dev/video0 ! video/x-raw, format=YUY2 ! videoconvert ! video/x-raw, format=BGR ! appsink"
video = cv2.VideoCapture(pipeline, cv2.CAP_GSTREAMER)
or
pipeline = (
"v4l2src device=/dev/video0 ! "
"video/x-raw,width=640,height=480,format=BGR ! "
"videoconvert ! "
"appsink drop=true sync=false"
)
video = cv2.VideoCapture(pipeline, cv2.CAP_GSTREAMER)
But I still get the same warnings :
[ WARN:[email protected]] global /output/build/opencv4-4.5.5/modules/videoio/src/cap_gstreamer.cpp (1226) open OpenCV | GStreamer warning: cannot find appsink in manual pipeline
[ WARN:[email protected]] global output/build/opencv4-4.5.5/modules/videoio/src/cap_gstreamer.cpp (862) isPipelinePlaying OpenCV | GStreamer warning: GStreamer: pipeline have not been created
v4l2-ctl --list-devices
outputs :
usb 1-3: reset high-speed USB device number 2
UVC Camera (046d:0825) (usb-500000.ehci-3):
/dev/video0
/dev/video1
/dev/media0
v4l2-ctl --list-formats-ext
returns :
usb 1-3: reset high-speed USB device number 2
ioctl: VIDIOC_ENUM_FMT
Type: Video Capture
[0]: 'YUYV' (YUYV 4:2:2)
Size: Discrete 640x480
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 160x120
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 176x144
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 320x176
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 320x240
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 352x288
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 432x240
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 544x288
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 640x360
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 752x416
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 800x448
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 800x600
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 864x480
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 960x544
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 960x720
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 1024x576
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 1184x656
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 1280x720
Interval: Discrete 0.133s (7.500 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 1280x960
Interval: Discrete 0.133s (7.500 fps)
Interval: Discrete 0.200s (5.000 fps)
[1]: 'MJPG' (Motion-JPEG, compressed)
Size: Discrete 640x480
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 160x120
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 176x144
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 320x176
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 320x240
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 352x288
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 432x240
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 544x288
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 640x360
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 752x416
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 800x448
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 800x600
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 864x480
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 960x544
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 960x720
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 1024x576
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 1184x656
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 1280x720
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
Size: Discrete 1280x960
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.040s (25.000 fps)
Interval: Discrete 0.050s (20.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Interval: Discrete 0.100s (10.000 fps)
Interval: Discrete 0.200s (5.000 fps)
I have read many many forums posts, but I can not find any solution that works for me,
Many thanks,
After some investigations, the Buildroot version I was using was corrupted in a non-evident way. Therefore, appsink was not installed while being selected in the menuconfig.
Moving to the latest version and building once again solved my issue.
To check the installed sinks, anyone can run :
gst-launch-1.0 | grep sink