不显示的视频帧坐标 PyQt

Question

我正在尝试使用 PyQt 制作视频流应用程序，我希望在单击它而不是显示时获取视频帧点的坐标。 我的意思是如果我的相机分辨率是 640*480 而我的显示器分辨率是 1920*1080 那么当我点击显示器右下角时我应该得到 (640, 480)

相机代码：

from PyQt4 import QtCore, QtGui
from threading import Thread
from collections import deque
from datetime import datetime
import time
import sys
import cv2
import imutils


class CameraWidget(QtGui.QWidget):
    """Independent camera feed
    Uses threading to grab IP camera frames in the background

    @param width - Width of the video frame
    @param height - Height of the video frame
    @param stream_link - IP/RTSP/Webcam link
    @param aspect_ratio - Whether to maintain frame aspect ratio or force into fraame
    """

    def __init__(self, width, height, stream_link=0, aspect_ratio=False, parent=None, deque_size=1):
        super(CameraWidget, self).__init__(parent)

        # Initialize deque used to store frames read from the stream
        self.deque = deque(maxlen=deque_size)

        self.screen_width = width
        self.screen_height = height
        self.maintain_aspect_ratio = aspect_ratio

        self.camera_stream_link = stream_link

        # Flag to check if camera is valid/working
        self.online = False
        self.capture = None
        self.video_frame = QtGui.QLabel()

        self.load_network_stream()

        # Start background frame grabbing
        self.get_frame_thread = Thread(target=self.get_frame, args=())
        self.get_frame_thread.daemon = True
        self.get_frame_thread.start()

        # Periodically set video frame to display
        self.timer = QtCore.QTimer()
        self.timer.timeout.connect(self.set_frame)
        self.timer.start(.5)

        print('Started camera: {}'.format(self.camera_stream_link))

    def load_network_stream(self):
        """Verifies stream link and open new stream if valid"""

        def load_network_stream_thread():
            if self.verify_network_stream(self.camera_stream_link):
                self.capture = cv2.VideoCapture(self.camera_stream_link)
                self.online = True
        self.load_stream_thread = Thread(target=load_network_stream_thread, args=())
        self.load_stream_thread.daemon = True
        self.load_stream_thread.start()

    def verify_network_stream(self, link):
        """Attempts to receive a frame from given link"""

        cap = cv2.VideoCapture(link)
        if not cap.isOpened():
            return False
        cap.release()
        return True

    def get_frame(self):
        """Reads frame, resizes, and converts image to pixmap"""

        while True:
            try:
                if self.capture.isOpened() and self.online:
                    # Read next frame from stream and insert into deque
                    status, frame = self.capture.read()
                    if status:
                        self.deque.append(frame)
                    else:
                        self.capture.release()
                        self.online = False
                else:
                    # Attempt to reconnect
                    print('attempting to reconnect', self.camera_stream_link)
                    self.load_network_stream()
                    self.spin(2)
                self.spin(.001)
            except AttributeError:
                pass

    def spin(self, seconds):
        """Pause for set amount of seconds, replaces time.sleep so program doesnt stall"""

        time_end = time.time() + seconds
        while time.time() < time_end:
            QtGui.QApplication.processEvents()

    def set_frame(self):
        """Sets pixmap image to video frame"""

        if not self.online:
            self.spin(1)
            return

        if self.deque and self.online:
            # Grab latest frame
            frame = self.deque[-1]

            # Keep frame aspect ratio
            if self.maintain_aspect_ratio:
                self.frame = imutils.resize(frame, width=self.screen_width)
            # Force resize
            else:
                self.frame = cv2.resize(frame, (self.screen_width, self.screen_height))
                self.frame = cv2.cvtColor(self.frame, cv2.COLOR_BGR2RGB)
                h, w, ch = self.frame.shape
                bytesPerLine = ch * w

            # Convert to pixmap and set to video frame
            self.img = QtGui.QImage(self.frame, w, h, bytesPerLine, QtGui.QImage.Format_RGB888)
            self.pix = QtGui.QPixmap.fromImage(self.img)
            self.video_frame.setPixmap(self.pix)

    def get_video_frame(self):
        return self.video_frame

这是我的 window 代码：

class Window(QtGui.QWidget):
    def __init__(self, cam=None, parent=None):
        super(Window, self).__init__(parent)

        self.showMaximized()

        self.screen_width = self.width()
        self.screen_height = self.height()

        # Create camera widget
        print('Creating Camera Widget...')
        self.camera = CameraWidget(self.screen_width, self.screen_height, cam)

        self.layout = QtGui.QVBoxLayout()
        self.layout.setContentsMargins(0,0,0,0)
        self.layout.setSpacing(0)
        self.layout.addWidget(self.camera.get_video_frame())
        self.setLayout(self.layout)

        self.camera.get_video_frame().mousePressEvent = self.getPos   

    def getPos(self , event):
        x = event.pos().x()
        y = event.pos().y()
        print('x,y: ', x, y)


camera = 'rtsp://admin:vaaan@123@192.168.1.51/Streaming/Channels/2'

if __name__=='__main__':
    app = QtGui.QApplication([])
    win = Window(camera)
    sys.exit(app.exec_())

Answer 1

不要使用 QLabel 来显示图像，因为很难 map 坐标，而是使用 QGraphicsPixmapItem：

from collections import deque
from datetime import datetime
import sys
from threading import Thread
import time

import cv2

from PyQt4 import QtCore, QtGui


class CameraWidget(QtGui.QGraphicsView):
    """Independent camera feed
    Uses threading to grab IP camera frames in the background

    @param width - Width of the video frame
    @param height - Height of the video frame
    @param stream_link - IP/RTSP/Webcam link
    @param aspect_ratio - Whether to maintain frame aspect ratio or force into fraame
    """

    def __init__(
        self,
        width,
        height,
        stream_link=0,
        aspect_ratio=False,
        parent=None,
        deque_size=1,
    ):
        super(CameraWidget, self).__init__(parent)

        # Initialize deque used to store frames read from the stream
        self.deque = deque(maxlen=deque_size)

        self.screen_width = width
        self.screen_height = height
        self.maintain_aspect_ratio = aspect_ratio

        self.camera_stream_link = stream_link

        # Flag to check if camera is valid/working
        self.online = False
        self.capture = None

        self.setScene(QtGui.QGraphicsScene(self))

        self._pixmap_item = self.scene().addPixmap(QtGui.QPixmap())

        self.load_network_stream()

        # Start background frame grabbing
        self.get_frame_thread = Thread(target=self.get_frame, args=())
        self.get_frame_thread.daemon = True
        self.get_frame_thread.start()

        # Periodically set video frame to display
        self.timer = QtCore.QTimer()
        self.timer.timeout.connect(self.set_frame)
        self.timer.start(0.5)

        print("Started camera: {}".format(self.camera_stream_link))

    def load_network_stream(self):
        """Verifies stream link and open new stream if valid"""

        def load_network_stream_thread():
            if self.verify_network_stream(self.camera_stream_link):
                self.capture = cv2.VideoCapture(self.camera_stream_link)
                self.online = True

        self.load_stream_thread = Thread(target=load_network_stream_thread, args=())
        self.load_stream_thread.daemon = True
        self.load_stream_thread.start()

    def verify_network_stream(self, link):
        """Attempts to receive a frame from given link"""

        cap = cv2.VideoCapture(link)
        if not cap.isOpened():
            return False
        cap.release()
        return True

    def get_frame(self):
        """Reads frame, resizes, and converts image to pixmap"""

        while True:
            try:
                if self.capture.isOpened() and self.online:
                    # Read next frame from stream and insert into deque
                    status, frame = self.capture.read()
                    if status:
                        self.deque.append(frame)
                    else:
                        self.capture.release()
                        self.online = False
                else:
                    # Attempt to reconnect
                    print("attempting to reconnect", self.camera_stream_link)
                    self.load_network_stream()
                    self.spin(2)
                self.spin(0.001)
            except AttributeError:
                pass

    def spin(self, seconds):
        """Pause for set amount of seconds, replaces time.sleep so program doesnt stall"""

        time_end = time.time() + seconds
        while time.time() < time_end:
            QtGui.QApplication.processEvents()

    def set_frame(self):
        """Sets pixmap image to video frame"""

        if not self.online:
            self.spin(1)
            return

        if self.deque and self.online:
            # Grab latest frame
            frame = self.deque[-1]

            frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
            h, w, ch = frame.shape
            bytesPerLine = ch * w

            # Convert to pixmap and set to video frame
            image = QtGui.QImage(frame, w, h, bytesPerLine, QtGui.QImage.Format_RGB888)
            pixmap = QtGui.QPixmap.fromImage(image.copy())
            self._pixmap_item.setPixmap(pixmap)
        self.fix_size()

    def mousePressEvent(self, event):
        super(CameraWidget, self).mousePressEvent(event)
        vp = event.pos()
        it = self.itemAt(vp)
        if it == self._pixmap_item:
            sp = self.mapToScene(vp)
            lp = it.mapFromScene(sp)
            self.clicked.emit(lp.toPoint())

    clicked = QtCore.pyqtSignal(QtCore.QPoint)

    def resizeEvent(self, event):
        self.fix_size()
        super().resizeEvent(event)

    def fix_size(self):
        self.fitInView(
            self._pixmap_item,
            QtCore.Qt.KeepAspectRatio
            if self.maintain_aspect_ratio
            else QtCore.Qt.IgnoreAspectRatio,
        )


class Window(QtGui.QWidget):
    def __init__(self, cam=None, parent=None):
        super(Window, self).__init__(parent)

        self.showMaximized()

        self.screen_width = self.width()
        self.screen_height = self.height()

        # Create camera widget
        print("Creating Camera Widget...")
        self.camera = CameraWidget(self.screen_width, self.screen_height, cam)

        lay = QtGui.QVBoxLayout(self)
        lay.setContentsMargins(0, 0, 0, 0)
        lay.setSpacing(0)
        lay.addWidget(self.camera)

        self.camera.clicked.connect(print)


camera = 0  # 'rtsp://admin:vaaan@123@192.168.1.51/Streaming/Channels/2'

if __name__ == "__main__":
    app = QtGui.QApplication([])
    win = Window(camera)
    sys.exit(app.exec_())