Human friendly video for linux
Project description
v4l2py
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.
Installation
From within your favorite python environment:
$ pip install v4l2py
Usage
Without further ado:
>>> from v4l2py import Device
>>> with Device.from_id(0) as cam:
>>> 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 bytes
Getting information about the device:
>>> from v4l2py.device import Device, BufferType
>>> cam = Device.from_id(0)
>>> cam.open()
>>> 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.get_format(BufferType.VIDEO_CAPTURE)
Format(width=640, height=480, pixelformat=<PixelFormat.MJPEG: 1196444237>}
>>> for ctrl in cam.controls.values(): print(ctrl)
<Control name=Brightness, type=INTEGER, min=0, max=255, step=1>
<Control name=Contrast, type=INTEGER, min=0, max=255, step=1>
<Control name=Saturation, type=INTEGER, min=0, max=100, step=1>
<Control name=Hue, type=INTEGER, min=-180, max=180, step=1>
<Control name=Gamma, type=INTEGER, min=90, max=150, step=1>
<Control name=White Balance Temperature, type=INTEGER, min=2800, max=6500, step=1>
<Control name=Sharpness, type=INTEGER, min=0, max=7, step=1>
<Control name=Backlight Compensation, type=INTEGER, min=0, max=2, step=1>
<Control name=Exposure (Absolute), type=INTEGER, min=4, max=1250, step=1>
asyncio
v4l2py is asyncio friendly:
$ python -m asyncio
>>> from v4l2py import Device
>>> with Device.from_id(0) as camera:
... async for frame in camera:
... print(f"frame {len(frame)}")
frame 10224
frame 10304
frame 10224
frame 10136
...
(check examples/basic_async.py)
gevent
v4l2py is also gevent friendly:
$ python
>>> from v4l2py import Device, GeventIO
>>> with Device.from_id(0, io=GeventIO) as camera:
... for frame in camera:
... print(f"frame {len(frame)}")
frame 10224
frame 10304
frame 10224
frame 10136
...
(check examples/basic_gevent.py and examples/web/app.py)
Bonus track
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:
for frame in cam:
yield b"--frame\r\nContent-Type: image/jpeg\r\n\r\n" + frame.data + 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 0.0.0.0
Point your browser to 127.0.0.1:5000 and you should see your camera rolling!
Migrating from 1.x to 2
A frame changed from a simple bytes object to a Frame which contains the data plus all frame metadata.
As a consequence, when migrating from 1.x to 2, you will need to cast
frame object with bytes or access the frame.data item:
Before:
with Device.from_id(0) as cam:
for frame in cam:
buff = io.BytesIO(frame)
Now:
with Device.from_id(0) as cam:
for frame in cam:
frame = bytes(frame) # or frame = frame.data
buff = io.BytesIO(frame)
References
See the linux/videodev2.h header file for details.
Video for Linux Two Specification <http://linuxtv.org/downloads/v4l-dvb-apis/ch07s02.html>
Release history Release notifications | RSS feed
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
Source Distribution
File details
Details for the file v4l2py-2.0.0.tar.gz.
File metadata
- Download URL: v4l2py-2.0.0.tar.gz
- Upload date:
- Size: 38.6 kB
- Tags: Source
- Uploaded using Trusted Publishing? No
- Uploaded via: twine/4.0.1 CPython/3.10.4
File hashes
| Algorithm | Hash digest | |
|---|---|---|
| SHA256 | e7cd2b045dbf61b93466b029703d98fb177dc5a257b7d4e394928d6bee4f0b42 |
|
| MD5 | cb95a1f8757ae0e2591a65780f669499 |
|
| BLAKE2b-256 | 7fbb209b48f5c3b820cf2a2a2d4206f52cd9207e842709487885e703d170eec2 |
