如何使用opencv调整youtube直播输出帧的大小

Question

这是我对编码和这个网站的开始。我正在做一个项目，我想使用openCV，但我有一个问题。我需要调整输出帧的大小，以便识别对象。我读过，那个相框的尺寸应该是416x416，但当我试图释放相框时，它仍然是常规尺寸。这是代码：

import pafy
import youtube_dl
import cv2
import numpy as np

url = "https://www.youtube.com/watch?v=WOn7m0_aYBw"
video = pafy.new(url)
best = video.getbest(preftype="mp4")
cap = cv2.VideoCapture()
cap.open(best.url)
net = cv2.dnn.readNet("yolov3.weights", "yolov3.cfg")
classes = []
with open("coco.names", "r") as f:
classes = [line.strip() for line in f.readlines()]
layer_names = net.getLayerNames()
output_layers =[layer_names[i[0] - 1] for i in net.getUnconnectedOutLayers()]
colors = np.random.uniform(0, 255, size=(len(classes), 3))

while True:
ret, frame = cap.read()
#   if ret == True:
img = cv2.imshow('frame',frame)
#cap.set(cv2.CAP_PROP_FRAME_WIDTH, 416)
#cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 416)
width = 416
height = 416
dim = (width, height)
img = cv2.resize(frame, dim, interpolation = cv2.INTER_AREA)
print(img.shape)
if cv2.waitKey(20) & 0xFF == ord('q'):
break
blob = cv2.dnn.blobFromImage(img, 0.00392, (416, 416), (0, 0, 0), True, crop=False)
net.setInput(blob)
outs = net.forward(output_layers)

print(img.shape)返回正确的大小，但我认为我释放了错误的窗口。如何更改此代码以释放正确大小的窗口？

Answer 1

您在调整大小之前显示了帧

while True:
ret, frame = cap.read()
width = 416
height = 416
dim = (width, height)
img = cv2.resize(frame, dim, interpolation = cv2.INTER_AREA)
print(img.shape)
cv2.imshow('frame',img)
if cv2.waitKey(20) & 0xFF == ord('q'):
break