CODEWITHSUNDEEP
pythoncwindowsctypeswebcam
LuckyCoder3607
LuckyCoder3607

Reputation: 65

How to capture a webcam photo in Python using ctypes on windows?

I do not want to use OpenCV, Pygame or ImageIO because all three are HUGE, and I want to compile my program into a binary, using any of these libraries is causing the output to be 100MB or more when I am only using one functionality of those libraries.

I know that it is possible to capture a photo using c/++ but I do not know a single thing about low-level programming languages. So I was hoping for help.

NOTE: If anyone knows how to do this in C/++ but not ctypes, no problem, just post it here and I can modify it into python ctypes syntax.

Upvotes: 1

Views: 108

Answers (2)

yushulx
yushulx

Reputation: 12160

I've published a lightweight Python camera library on PyPI: https://pypi.org/project/lite-camera/

enter image description here

To use it:

import litecam

camera = litecam.PyCamera()

if camera.open(0):

    window = litecam.PyWindow(
        camera.getWidth(), camera.getHeight(), "Camera Stream")

    while window.waitKey('q'):
        frame = camera.captureFrame()
        if frame is not None:
            width = frame[0]
            height = frame[1]
            size = frame[2]
            data = frame[3]
            window.showFrame(width, height, data)

    camera.release()

Upvotes: 2

RizzlaTech
RizzlaTech

Reputation: 26

Which OS are you using ? im adding an example to open /dev/video0 and capture a frame on linux using the built in V4L2 (I am unfamiliar with the windows alternative)

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/ioctl.h>
#include <linux/videodev2.h>
#include <sys/mman.h>

int main() {
    int fd = open("/dev/video0", O_RDWR);  // Open the video device
    if (fd == -1) {
        perror("Opening video device");
        return 1;
    }

    struct v4l2_capability cap;
    if (ioctl(fd, VIDIOC_QUERYCAP, &cap) == -1) {
        perror("Querying Capabilities");
        return 1;
    }

    struct v4l2_format fmt;
    fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    fmt.fmt.pix.width = 640;
    fmt.fmt.pix.height = 480;
    fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_MJPEG;  // Set format to MJPEG
    fmt.fmt.pix.field = V4L2_FIELD_NONE;
    
    if (ioctl(fd, VIDIOC_S_FMT, &fmt) == -1) {
        perror("Setting Pixel Format");
        return 1;
    }

    struct v4l2_requestbuffers req;
    req.count = 1;  // Request a single buffer
    req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    req.memory = V4L2_MEMORY_MMAP;

    if (ioctl(fd, VIDIOC_REQBUFS, &req) == -1) {
        perror("Requesting Buffer");
        return 1;
    }

    struct v4l2_buffer buf;
    memset(&buf, 0, sizeof(buf));
    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    buf.memory = V4L2_MEMORY_MMAP;
    buf.index = 0;

    if (ioctl(fd, VIDIOC_QUERYBUF, &buf) == -1) {
        perror("Querying Buffer");
        return 1;
    }

    void* buffer = mmap(NULL, buf.length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, buf.m.offset);

    if (buffer == MAP_FAILED) {
        perror("mmap");
        return 1;
    }

    if (ioctl(fd, VIDIOC_STREAMON, &buf.type) == -1) {
        perror("Stream On");
        return 1;
    }

    // Queue the buffer
    if (ioctl(fd, VIDIOC_QBUF, &buf) == -1) {
        perror("Queue Buffer");
        return 1;
    }

    // Dequeue the buffer
    if (ioctl(fd, VIDIOC_DQBUF, &buf) == -1) {
        perror("Dequeue Buffer");
        return 1;
    }

    FILE* out = fopen("capture.jpg", "wb");
    if (!out) {
        perror("Cannot open image");
        return 1;
    }

    fwrite(buffer, buf.bytesused, 1, out);  // Save buffer to JPEG
    fclose(out);

    munmap(buffer, buf.length);
    close(fd);

    return 0;
}

Ive used this for a MATLAB project, to capture and analyse binning of pixels on a certain display and camera. I hope it helps

Upvotes: 1

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