创建 OpenCV 视频小部件以在 Kivy 中使用答案

【问题标题】：Create OpenCV Video Widgets to use in Kivy创建 OpenCV 视频小部件以在 Kivy 中使用
【发布时间】：2020-02-19 14:03:21
【问题描述】：

我想在 Kivy 的盒子布局中显示 2 到 4 个 rtsp 流，但我似乎不知道如何使用 kv 语言来实现这一点。我可以使用此代码显示一台相机：

class KivyCamera(Image):
    def __init__(self, capture, fps, **kwargs):
        super(KivyCamera, self).__init__(**kwargs)
        self.capture = capture
        Clock.schedule_interval(self.update, 1.0 / fps)

    def update(self, dt):
        ret, frame = self.capture.read()
        if ret:
            # convert it to texture
            buf1 = cv2.flip(frame, 0)
            buf = buf1.tostring()
            image_texture = Texture.create(
                size=(frame.shape[1], frame.shape[0]), colorfmt='bgr')
            image_texture.blit_buffer(buf, colorfmt='bgr', bufferfmt='ubyte')
            # display image from the texture
            self.texture = image_texture


class CamApp(App):
    def build(self):
        self.capture = cv2.VideoCapture('stream address removed for stack overflow')
        self.my_camera = KivyCamera(capture=self.capture, fps=30)
        return self.my_camera

    def on_stop(self):
        #without this, app will not exit even if the window is closed
        self.capture.release()


if __name__ == '__main__':
    CamApp().run()

不过，这只是使用 .py。我希望能够使用 kv 语言创建 KivyCamera 实例并为每个实例设置不同的 capture 值。

例如：

BoxLayout:
        orientation: 'horizontal'

        KivyCamera:
            capture: 'myvalue'
            pos_hint: {'left': 1}

        KivyCamera:
            capture: 'anothervalue'
            pos_hint: {'right': 1}

【问题讨论】：

嗯，在 python 中，capture 属性显然是 VideoCapture，但在 .kv 中你使用字符串你认为它合乎逻辑吗？
我明白这一点。我的例子更像是一个占位符的想法。我如何将 VideoCapture 放在那里？

标签： python opencv kivy rtsp

【解决方案1】：

您可以将属性设为 fps 和源（索引、文件名等），而不是 VideoCapture：

main.py

from kivy.app import App
from kivy.uix.image import Image
from kivy.clock import Clock
from kivy.graphics.texture import Texture
from kivy.properties import ObjectProperty, NumericProperty

import cv2

class KivyCamera(Image):
    source = ObjectProperty()
    fps = NumericProperty(30)

    def __init__(self, **kwargs):
        super(KivyCamera, self).__init__(**kwargs)
        self._capture = None
        if self.source is not None:
            self._capture = cv2.VideoCapture(self.source)
        Clock.schedule_interval(self.update, 1.0 / self.fps)

    def on_source(self, *args):
        if self._capture is not None:
            self._capture.release()
        self._capture = cv2.VideoCapture(self.source)

    @property
    def capture(self):
        return self._capture

    def update(self, dt):
        ret, frame = self.capture.read()
        if ret:
            buf1 = cv2.flip(frame, 0)
            buf = buf1.tostring()
            image_texture = Texture.create(
                size=(frame.shape[1], frame.shape[0]), colorfmt="bgr"
            )
            image_texture.blit_buffer(buf, colorfmt="bgr", bufferfmt="ubyte")
            self.texture = image_texture


class CamApp(App):
    pass


if __name__ == "__main__":
    CamApp().run()

cam.kv

BoxLayout:
    orientation: 'horizontal'

    KivyCamera:
        source: "stream address removed for stack overflow"

【讨论】：