vpl
Vide Pipe Line
installation
Run pip3 install vpl (it's on pypi)
Or pip3 install -e git://github.com/chemicaldevelopment/vpl (for development, i.e. unstable builds)
usage
You can use import vpl in your code
Commandline
It comes with a simple viewer, run:
python3 -mvpl video 0
You can change 0 to higher numbers if you have multiple cameras connected. Or, you can change it to a file name to use the video as input:
python3 -mvpl video ~/path/video.mp4
To record, use -o:
python3 -mvpl video 0 -o tmp/{num}.jpg
The recording to video is glitchy, so it is recomended to render to individual frames
Creating a video
Say you have output to tmp/{num}.jpg at 24 frames per second, and you want to create a .mp4 file
You can do this with:
ffmpeg -r 24 -i tmp/%08d.jpg -c:v libx264 -vf fps=24 -pix_fmt yuv420p out.mp4
exposure settings
Exposure settings are extremely finicky to get working. Here's a few commands to try:
First, set the auto control cutoff to 1:
v4l2-ctl -d /dev/video0 -c exposure_auto=1
Then, try setting the exposure value to various values between -100 and +100:
v4l2-ctl -d /dev/video0 -c exposure_absolute=-30
v4l2-ctl -d /dev/video0 -c exposure_absolute=0
v4l2-ctl -d /dev/video0 -c exposure_absolute=0.5
v4l2-ctl -d /dev/video0 -c exposure_absolute=20
The optimal low/medium light setting for the Micro$oft Lifecam is:
v4l2-ctl -d /dev/video0 -c exposure_absolute=20.9
Use this command:
v4l2-ctl --all
to print settings (and their defaults). This is the most important v4l command
Run through setting all these to defaults
Here are the defaults for Micro$oft Lifecam:
Streaming Parameters Video Capture:
Capabilities : timeperframe
Frames per second: 30.000 (30/1)
Read buffers : 0
brightness (int) : min=30 max=255 step=1 default=133 value=133
contrast (int) : min=0 max=10 step=1 default=5 value=5
saturation (int) : min=0 max=200 step=1 default=83 value=83
white_balance_temperature_auto (bool) : default=1 value=1
power_line_frequency (menu) : min=0 max=2 default=2 value=2
white_balance_temperature (int) : min=2800 max=10000 step=1 default=4500 value=4500 flags=inactive
sharpness (int) : min=0 max=50 step=1 default=25 value=25
backlight_compensation (int) : min=0 max=10 step=1 default=0 value=5
exposure_auto (menu) : min=0 max=3 default=1 value=1
exposure_absolute (int) : min=5 max=20000 step=1 default=156 value=40
pan_absolute (int) : min=-201600 max=201600 step=3600 default=0 value=0
tilt_absolute (int) : min=-201600 max=201600 step=3600 default=0 value=0
zoom_absolute (int) : min=0 max=10 step=1 default=0 value=0
Use the script utils/reset_lifecam.sh