Hi,

i added a gui sample using your library. it works quite well and shows basic operation nicely. if you are interested let me know and i create a pull request.

regards, michael

This module won't build under python 3:

v4l2capture.c: In function ‘Video_device_dealloc’:
v4l2capture.c:116:7: error: ‘Video_device’ has no member named ‘ob_type’

If I attempt to work around that my hackily commenting it out, the module builds but can't be imported:

ImportError: ./v4l2capture.so: undefined symbol: PyString_FromStringAndSize

That can be fixed by using PyBytes_* instead of PyString_*, but then:

ImportError: ./v4l2capture.so: undefined symbol: PyInt_FromLong

So I try to change that to PyLong_FromLong as suggested here and here

After fixing that, the next problem is:

ImportError: ./v4l2capture.so: undefined symbol: Py_InitModule3

According to here I should change that to InitModule, not InitModule3 or 4. But:

ImportError: ./v4l2capture.so: undefined symbol: Py_InitModule

So, following a suggestion here to link with --export-dynamic, I tried modifying:

gcc -pthread -shared -Wl,-O1 -Wl,-Bsymbolic-functions -Wl,-z,relro build/temp.linux-armv6l-3.2/v4l2capture.o -lv4l2 -o build/lib.linux-armv6l-3.2/v4l2capture.cpython-32mu.so

to

gcc -pthread -shared -Wl,-O1 -Wl,-Bsymbolic-functions -Wl,--export-dynamic -Wl,-z,relro build/temp.linux-armv6l-3.2/v4l2capture.o -lv4l2 -o build/lib.linux-armv6l-3.2/v4l2capture.cpython-32mu.so

but the error remains the same:

ImportError: ./v4l2capture.so: undefined symbol: Py_InitModule

At this point, I reached the limit of my ability to hack around with this, and I need an adult. Any ideas for what might be needed to make this module compatible with python 3?

Dear Gerbart,

Thank you for the awesome python wrapper for v4l2!!!

I running into an issue when v4l2capture can not find a device at the specified path. I have a try/catch statement surrounding the opening of the video device in case the user specifies an incorrect path:

import v4l2capture as vc
try:
    self.cam = vc.Video_device(self.cnfg['devLoc'])       
except:
    ...

As one might expect, for an incorrect path an IOError is returned:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IOError: [Errno 2] No such file or directory: '/dev/video5/'

However, unexpectedly, python is immediately terminated as well, whether it be a program or python interactive shell. Is there a way to handle this such that the python shell or program is not immediately terminated?

Thanks!!

hi,

i wonder how i can get the features that a webcam supports. if i use my favourite webcam tool guvcview it shows possible resolution and fps settings. did i miss something or does guvcview use a different api for that or is it just not implemented for now?

regards, michael

Hi,

Thank you for the amazing code . I am using it to stream stereo feeds from 2 webcams (logitech c930e) to my laptop from a raspberry pi. It works most times and when it does it rarely stops. However sometimes i get the following error.
libv4l2: error dequeuing buf: Broken pipe

The quick fix is to disconnect the webcams and reconnect them. From debugging i have narrowed it to the following line:

image_data = video.read_and_queue()

Have you encountered this error before ?

Raspberry pi uses Ubuntu Mate 16.0.4 and is connected to my laptop via wifi on a private dedicated network.

Hello,

I implemented your code (from capture_video.py) into my own Python script, I tried a lot of thing to edit the format (from MJPG to something else like avi or mp4). How can we record into the avi format ?

What I tried to edit:
Line 41: video.mjpg > video.avi
Line 26: fourcc='MJPG' > I tried a lot of codecs which were compatible with AVI format but no one was able to work. (from this list: http://www.fourcc.org/codecs.php)

I never succeeded to display the result on VLC

Sorry for my english, I'm French,

Thank you

my code like this:

while True:
    # top_cam and bot_cam is camera device
    select.select([top_cam,bot_cam],(),())
    #select.select([top_cam],(),())
    #select.select([bot_cam],(),())
    data1= top_cam.read_and_queue()
    data2 =  bot_cam.read_and_queue()

it will appear error :

libv4l2: error dequeuing buf: Resource temporarily unavailable
Traceback (most recent call last):
  File "cam_test2.py", line 105, in <module>
    data2 =  bot_cam.read_and_queue()
BlockingIOError: [Errno 11] Resource temporarily unavailable

but when i comment select.select([top_cam,bot_cam],(),()) ,and replace in select.select([top_cam],(),());select.select([bot_cam],(),()).

The biggest problem is when i use the latter，it will appear some image is None.

so I want use select.select([top_cam,bot_cam],(),()) ,what should I do?

thanks!

I am not good at English

I'm getting an error with the image_capture script:

python capture_picture.py 
Traceback (most recent call last):
  File "capture_picture.py", line 43, in <module>
    image_data = video.read()
IOError: [Errno 11] Resource temporarily unavailable

It seems to be installed ok:

python list_devices.py 
/dev/video0
    driver:       STV06xx
    card:         Camera
    bus info:     usb-bcm2708_usb-1.2
    capabilities: readwrite, streaming, video_capture