如何将缓冲区添加到视频输出中？视频源来自具有许多过滤/滞后的私人相机

Question

有什么方法可以添加缓冲区，以便帧每秒从相机源收集足够的图像？因为到目前为止，视频输出落后了很糟糕。

该代码运行良好，不会崩溃，但是它会滞后直到屏幕不再移动。

添加缓冲区是否更容易，还是可以绕过实际视频源制成的滞后/悬挂？

import cv2
import numpy as np

# Resolution Pixel Size
# 640 x 480 - Standard Definition(SD)
# 1280 x 720 - High Definition(HD)
# 1920 x 1080 - Ultra High Definiion(HD+)
# 3840 x 2160 - Ultra High Definition(UHD or 2K)

cyanColor = (255, 255, 0)
pinkColor = (255, 0, 255)
yellowColor = (0, 255, 255)
greenColor = (0, 255, 0)
blueColor = (255, 0, 0)
redColor = (0,0,255)

path_vid = "Resources/video/license_plate.mp4"
path_main_ent = 'rtsp://~~~/Streaming/Channels/101'
path_parking_Lot = 'rtsp://~~~/Streaming/Channels/101'


button_person = False
button_car = False
button_truck = False

counter = 0
nmsThreshold = 0.3
confThreshold = 0.4

def rescale_frame(image, percentage):
    width = int(image.shape[1] * percentage / 100)
    height = int(image.shape[0] * percentage / 100)
    new_frame = (width, height)
    return cv2.resize(image, new_frame, interpolation=cv2.INTER_AREA)

def click_button(event,x,y,flags,params):
    global button_person
    global button_car
    global button_truck

    if event == cv2.EVENT_LBUTTONDOWN:
        print(x,y)

        #   ------  Person Button Clicking  ---------
        polygon_person = np.array([[(20, 160), (200, 160), (200, 230), (20, 230)]])
        is_inside_person_button = cv2.pointPolygonTest(polygon_person,(x,y),False)
        if is_inside_person_button>0:
            print("YAYYYY, We're clicking inside Button!!",x,y)

            if button_person is False:
                button_person = True
            else:
                button_person = False

            print("Now Person Button is: ",button_person)

        #   ------  Car Button Clicking  ---------
        polygon_car = np.array([[(20, 250), (200, 250), (200, 320), (20, 320)]])
        is_inside_car_button = cv2.pointPolygonTest(polygon_car, (x, y), False)
        if is_inside_car_button > 0:
            print("YAYYYY, We're clicking inside Button!!", x, y)

            if button_car is False:
                button_car = True
            else:
                button_car = False

            print("Now Car Button is: ", button_car)

        #   ------  Truck Button Clicking  ---------
        polygon_truck = np.array([[(20, 340), (200, 340), (200, 410), (20, 410)]])
        is_inside_truck_button = cv2.pointPolygonTest(polygon_truck, (x, y), False)
        if is_inside_truck_button > 0:
            print("YAYYYY, We're clicking inside Button!!", x, y)

            if button_truck is False:
                button_truck = True
            else:
                button_truck = False

            print("Now Truck Button is: ", button_truck)

# net = cv2.dnn.readNet("dnn_model/yolov3.weights", "dnn_model/yolov3.cfg")
# net = cv2.dnn.readNet("dnn_model/yolov3-spp.weights", "dnn_model/yolov3-spp.cfg")
# net = cv2.dnn.readNet("dnn_model/yolov3-tiny.weights", "dnn_model/yolov3-tiny.cfg")
# net = cv2.dnn.readNet("dnn_model/yolov4.weights", "dnn_model/yolov4.cfg")
net = cv2.dnn.readNet("dnn_model/yolov4-tiny.weights", "dnn_model/yolov4-tiny.cfg")

model = cv2.dnn_DetectionModel(net)
model.setInputParams(size=(640,480), scale=1/255)

classes = []
with open("dnn_model/classes.txt","r") as file_object:
    for class_name in file_object.readlines():
        class_name = class_name.strip()
        classes.append(class_name)

# print("- Object List -")
# print(classes[0])

cap = cv2.VideoCapture(path_main_ent)
# cap = cv2.VideoCapture(path_parking_Lot)

cv2.namedWindow("Frame")    # The name should be same with cv2.imshow("_Name_")
cv2.setMouseCallback("Frame",click_button)

while True:
    ret,frame = cap.read()
    # print(type(frame))
    if not ret:
        continue

    img_frame_90 = rescale_frame(frame, 90)

    line_frame_above = cv2.line(img_frame_90, (190, 430), (1220, 470), yellowColor, 2)
    line_frame = cv2.line(img_frame_90, (180, 440), (1220, 480), blueColor, 4)
    line_frame_bottom = cv2.line(img_frame_90, (170, 450), (1220, 490), yellowColor, 2)

    polygon_person = np.array([[(20, 160), (200, 160), (200, 230), (20, 230)]])
    cv2.fillPoly(img_frame_90, polygon_person, greenColor)
    cv2.putText(img_frame_90, "Person", (50, 200), cv2.FONT_HERSHEY_PLAIN, 2, blueColor, 2)

    polygon_car = np.array([[(20, 250), (200, 250), (200, 320), (20, 320)]])
    cv2.fillPoly(img_frame_90, polygon_car, greenColor)
    cv2.putText(img_frame_90, "Car", (50, 290), cv2.FONT_HERSHEY_PLAIN, 2, blueColor, 2)

    polygon_truck = np.array([[(20, 340), (200, 340), (200, 410), (20, 410)]])
    cv2.fillPoly(img_frame_90, polygon_truck, greenColor)
    cv2.putText(img_frame_90, "Truck", (50, 380), cv2.FONT_HERSHEY_PLAIN, 2, blueColor, 2)

    # polygon_truck = np.array([[(20, 430), (200, 430), (200, 500), (20, 500)]])
    # cv2.fillPoly(img_frame_90, polygon_truck, greenColor)
    # cv2.putText(img_frame_90, "Bus", (50, 470), cv2.FONT_HERSHEY_PLAIN, 2, blueColor, 2)

    (class_ids, scores, bboxes) = model.detect(img_frame_90,nmsThreshold=nmsThreshold, confThreshold=confThreshold)

    if len(class_ids) != 0:
        for class_id, score, bbox in zip(class_ids,scores,bboxes):
            (x,y,w,h) = bbox
            class_name = classes[class_id]
            xmid = int((x + (x + w)) / 2)
            ymid = int((y + (y + h)) / 2)

            if class_name == "person" and button_person is True:
                cv2.rectangle(img_frame_90, (x, y), (x + w, y + h), pinkColor, 2)
                cv2.circle(img_frame_90, (xmid, ymid), 3, redColor, -1)
                # cv2.putText(img_frame_90,str(class_name),(x,y-10),cv2.FONT_HERSHEY_SIMPLEX,1,yellowColor,2)
                if ymid > 431 and ymid < 500 and xmid > 170 and xmid <1220:
                    line_frame = cv2.line(img_frame_90, (350, 440), (1220, 480), greenColor, 4)
                    counter += 1

            if class_name == "car" and button_car is True:
                cv2.rectangle(img_frame_90, (x, y), (x + w, y + h), greenColor, 2)
                cv2.circle(img_frame_90, (xmid, ymid), 3, redColor, -1)
                # cv2.putText(img_frame_90,str(class_name),(x,y-10),cv2.FONT_HERSHEY_SIMPLEX,1,yellowColor,2)
                if ymid > 431 and ymid < 507:
                    line_frame = cv2.line(img_frame_90, (350, 440), (1220, 480), greenColor, 4)
                    counter += 1

            if class_name == "truck" and button_truck is True:
                cv2.rectangle(img_frame_90, (x, y), (x + w, y + h), cyanColor, 2)
                cv2.circle(img_frame_90, (xmid, ymid), 3, redColor, -1)
                # cv2.putText(img_frame_90,str(class_name),(x,y-10),cv2.FONT_HERSHEY_SIMPLEX,1,yellowColor,2)
                if ymid > 431 and ymid < 507:
                    line_frame = cv2.line(img_frame_90, (350, 440), (1220, 480), greenColor, 4)
                    counter += 1

    cv2.putText(img_frame_90, 'Total Vehicles : {}'.format(counter), (0, 100), cv2.FONT_HERSHEY_SIMPLEX, 2, yellowColor,2)

    cv2.imshow("Frame",img_frame_90)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()

Answer 1

添加此类并更改代码的几行。这将使用最新的帧。

您的代码：

while True:
    ret,frame = cap.read()
    # print(type(frame))
    if not ret:
        continue

新代码：

cam = CameraBufferCleanerThread(cap)
while True:
    frame = cam.last_frame
    if frame is None:
        continue

示例代码：

from threading import Thread
import cv2

class CameraBufferCleanerThread(Thread):
    def __init__(self, camera, name='camera-buffer-cleaner-thread'):
        self.camera = camera
        self.last_frame = None
        super(CameraBufferCleanerThread, self).__init__(name=name)
        self.start()

    def run(self):
        while True:
            ret, self.last_frame = self.camera.read()


if __name__ == '__main__':
    cap = cv2.VideoCapture("your/camera/url")
    cam = CameraBufferCleanerThread(cap)
    while True:
        frame = cam.last_frame
        if frame is None:
            continue
        else:
            cv2.imshow('frame', frame)
            if cv2.waitKey(1) & 0xFF == ord('q'):
                break
    cv2.destroyAllWindows()