image_to_v4l2loopback

ROS node for streaming an image topic to a video capture device. Mostly based on this:

• virtual_camera

dev

Setup a workspace:

cd ~/catkin_ws/src  # or wherever catkin_ws is
git clone https://github.com/lucasw/image_to_v4l2loopback
cd ..
catkin build image_to_v4l2loopback

video devices

Stream node needs to write to a video capture device, which varies depending on your system.

linux

Uses v4l2-loopback:

Secure boot uefi will prevent the modprobe from working, try https://askubuntu.com/questions/762254/why-do-i-get-required-key-not-available-when-install-3rd-party-kernel-modules

sudo apt install mokutil
sudo mokutil --disable-validation
sudo reboot

# don't bother this version is too old
# sudo apt-get install v4l2loopback-*

But the ubuntu v4l2loopback is old if it doesn't work, try

git clone git@github.com:umlaeute/v4l2loopback
cd v4l2loopback
make
sudo insmod v4l2loopback.ko exclusive_caps=1 video_nr=1 card_label="Fake"

See https://github.com/umlaeute/v4l2loopback for more instructions

sudo modprobe v4l2loopback video_nr=1
v4l2-ctl -D -d /dev/video1
Driver Info (not using libv4l2):
    Driver name   : v4l2 loopback
    Card type     : Dummy video device (0x0000)
    Bus info      : v4l2loopback:0
    Driver version: 0.8.0
    Capabilities  : 0x05000003
        Video Capture
        Video Output
        Read/Write
        Streaming

usage

stream

Typically just:

rosrun image_to_v4l2loopback stream _device:=/dev/video1 _width:=640 _height:=480 _fourcc:=YV12 image:=/my_camera/image

That resolution will then be locked in, need to rmmod and restart the module then set the resolution again.

where:

• /dev/video1 target device
• 640x480 target size
• YV12 target pixel format
• /my_camera/image the source sensor_msgs/Image topic re-mapped to image

For more:

rosrun image_to_v4l2loopback stream --help

cheese works, but guvcview does not.

Google hangouts says no camera found.

zoom-client works.

tests

v4l2-ctl -D -d /dev/video1
Driver Info (not using libv4l2):
    Driver name   : v4l2 loopback
    Card type     : Dummy video device (0x0000)
    Bus info      : v4l2loopback:0
    Driver version: 0.8.0
    Capabilities  : 0x05000003
        Video Capture
        Video Output
        Read/Write
        Streaming
ROS_VIRTUAL_CAM_STREAM_TEST_DEVICE=/dev/video1 catkin_make run_tests

If you want coverage:

catkin_make -DCMAKE_BUILD_TYPE=Debug -DCOVERAGE=ON
ROS_VIRTUAL_CAM_STREAM_TEST_DEVICE=/dev/video1 catkin_make run_tests
lcov --path . --directory . --capture --output-file coverage.info
lcov --remove coverage.info 'tests/*' '/usr/*' '/opt/*' --output-file coverage.info
lcov --list coverage.info