I am using a PI 4 with 64 bit os bullseye.
python 3.7.7
opencv-python 4.5.5.62
I am able to access pi cam from libcamera, i am also able to read a mp4 video using opencv; however when running opencv videocapture function, read method returns empty ret value. see code below:
import numpy as np
import cv2 as cv
cap = cv.VideoCapture(-1)
if not cap.isOpened():
print("Cannot open camera")
exit()
while True:
# Capture frame-by-frame
ret, frame = cap.read()
# if frame is read correctly ret is True
if not ret:
print("Can't receive frame (stream end?). Exiting ...")
break
# Our operations on the frame come here
gray = cv.cvtColor(frame, cv.COLOR_BGR2GRAY)
# Display the resulting frame
cv.imshow('frame', gray)
if cv.waitKey(1) == ord('q'):
break
# When everything done, release the capture
cap.release()
cv.destroyAllWindows()
ERROR:
(virtenv3.7) pi@pi:~ $ python opcvtest.py
Can't receive frame (stream end?). Exiting ...
(virtenv3.7) pi@pi:~ $
Opencv build info:
General configuration for OpenCV 4.5.5 =====================================
Version control: unknown
Platform:
Timestamp: 2022-02-05T09:15:14Z
Host: Linux 5.10.92-v8+ aarch64
CMake: 3.22.2
CMake generator: Unix Makefiles
CMake build tool: /usr/bin/gmake
Configuration: Release
CPU/HW features:
Baseline: NEON FP16
C/C++:
Built as dynamic libs?: NO
C++ standard: 11
C++ Compiler: /usr/bin/c++ (ver 10.2.1)
C++ flags (Release): -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Wsuggest-override -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG -DNDEBUG
C++ flags (Debug): -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Wsuggest-override -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -g -O0 -DDEBUG -D_DEBUG
C Compiler: /usr/bin/cc
C flags (Release): -fsigned-char -W -Wall -Werror=return-type -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -O3 -DNDEBUG -DNDEBUG
C flags (Debug): -fsigned-char -W -Wall -Werror=return-type -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -g -O0 -DDEBUG -D_DEBUG
Linker flags (Release): -Wl,--gc-sections -Wl,--as-needed
Linker flags (Debug): -Wl,--gc-sections -Wl,--as-needed
ccache: NO
Precompiled headers: NO
Extra dependencies: /usr/lib/aarch64-linux-gnu/libjpeg.so /usr/lib/aarch64-linux-gnu/libpng.so /usr/lib/aarch64-linux-gnu/libtiff.so /usr/lib/aarch64-linux-gnu/libz.so dl m pthread rt
3rdparty dependencies: libprotobuf ade ittnotify libwebp libopenjp2 IlmImf quirc tegra_hal
OpenCV modules:
To be built: calib3d core dnn features2d flann gapi highgui imgcodecs imgproc ml objdetect photo python3 stitching video videoio
Disabled: world
Disabled by dependency: -
Unavailable: java python2 ts
Applications: -
Documentation: NO
Non-free algorithms: NO
GUI: GTK3
GTK+: YES (ver 3.24.24)
GThread : YES (ver 2.66.8)
GtkGlExt: NO
VTK support: NO
Media I/O:
ZLib: /usr/lib/aarch64-linux-gnu/libz.so (ver 1.2.11)
JPEG: /usr/lib/aarch64-linux-gnu/libjpeg.so (ver 62)
WEBP: build (ver encoder: 0x020f)
PNG: /usr/lib/aarch64-linux-gnu/libpng.so (ver 1.6.37)
TIFF: /usr/lib/aarch64-linux-gnu/libtiff.so (ver 42 / 4.2.0)
JPEG 2000: build (ver 2.4.0)
OpenEXR: build (ver 2.3.0)
HDR: YES
SUNRASTER: YES
PXM: YES
PFM: YES
Video I/O:
DC1394: YES (2.2.6)
FFMPEG: YES
avcodec: YES (58.91.100)
avformat: YES (58.45.100)
avutil: YES (56.51.100)
swscale: YES (5.7.100)
avresample: NO
GStreamer: NO
v4l/v4l2: YES (linux/videodev2.h)
Parallel framework: pthreads
Trace: YES (with Intel ITT)
Other third-party libraries:
Lapack: NO
Eigen: YES (ver 3.3.9)
Custom HAL: YES (carotene (ver 0.0.1))
Protobuf: build (3.19.1)
OpenCL: YES (no extra features)
Include path: /tmp/pip-install-m36v8df1/opencv-python/opencv/3rdparty/include/opencl/1.2
Link libraries: Dynamic load
Python 3:
Interpreter: /home/pi/virtenv3.7/bin/python3.7 (ver 3.7.6)
Libraries: /usr/local/lib/libpython3.7m.a (ver 3.7.6)
numpy: /tmp/pip-build-env-_z0k49zk/overlay/lib/python3.7/site-packages/numpy/core/include (ver 1.19.3)
install path: python/cv2/python-3
Python (for build): /home/pi/virtenv3.7/bin/python3.7
Java:
ant: NO
JNI: NO
Java wrappers: NO
Java tests: NO
Install to: /tmp/pip-install-m36v8df1/opencv-python/_skbuild/linux-aarch64-3.7/cmake-install
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