Video for linux 2 (V4L2) python library
A two purpose API:
- high level Device API for humans to play with :-)
- raw python binding for the v4l2 (video4linux2) userspace API, using ctypes (don't even bother wasting your time here. You probably won't use it)
Only works on python >= 3.7.
From within your favorite python environment:
$ pip install v4l2pyWithout further ado:
>>> from v4l2py import Device
>>> cam = Device.from_id(0)
>>> for i, frame in enumerate(cam):
... print(f"frame #{i}: {len(frame)} bytes")
... if i > 9:
... break
...
frame #0: 54630 bytes
frame #1: 50184 bytes
frame #2: 44054 bytes
frame #3: 42822 bytes
frame #4: 42116 bytes
frame #5: 41868 bytes
frame #6: 41322 bytes
frame #7: 40896 bytes
frame #8: 40844 bytes
frame #9: 40714 bytes
frame #10: 40662 bytesGetting information about the device:
>>> from v4l2py import Device
>>> cam = Device.from_id(0)
>>> cam.info.card
'Integrated_Webcam_HD: Integrate'
>>> cam.info.capabilities
<Capability.STREAMING|EXT_PIX_FORMAT|VIDEO_CAPTURE: 69206017>
>>> cam.info.formats
[ImageFormat(type=<BufferType.VIDEO_CAPTURE: 1>, description=b'Motion-JPEG',
flags=<ImageFormatFlag.COMPRESSED: 1>, pixelformat=<PixelFormat.MJPEG: 1196444237>),
ImageFormat(type=<BufferType.VIDEO_CAPTURE: 1>, description=b'YUYV 4:2:2',
flags=<ImageFormatFlag.0: 0>, pixelformat=<PixelFormat.YUYV: 1448695129>)]
>>> cam.video_capture.get_format()
Format(width=640, height=480, pixelformat=<PixelFormat.MJPEG: 1196444237>}You've been patient enough to read until here so, just for you, a 20 line gem: a flask web server displaying your device on the web:
$ pip install flask# web.py
import flask
from v4l2py import Device
app = flask.Flask('basic-web-cam')
def gen_frames():
with Device.from_id(0) as cam:
cam.video_capture.set_format(640, 480, 'MJPG')
for frame in cam:
yield b"--frame\r\nContent-Type: image/jpeg\r\n\r\n" + frame + b"\r\n"
@app.route("/")
def index():
return '<html><img src="/stream" /></html>'
@app.route("/stream")
def stream():
return flask.Response(
gen_frames(), mimetype='multipart/x-mixed-replace; boundary=frame')run with:
$ FLASK_APP=web flask run -h 0.0.0.0Point your browser to 127.0.0.1:5000 and you should see your camera rolling!
See the linux/videodev2.h header file for details.
Video for Linux Two Specification <http://linuxtv.org/downloads/v4l-dvb-apis/ch07s02.html>