我正在嘗試使用 opencv 重新調整視頻大小，然后將其保存回我的系統。代碼有效并且不會給出任何錯誤，但輸出視頻文件已損壞。我使用的 fourcc 是 mp4v，與 .mp4 配合良好，但輸出視頻仍然損壞。需要幫忙。import numpy as np import cv2 import sys import re vid="" if len(sys.argv)==3: vid=sys.argv[1] compress=int(sys.argv[2]) else: print("File not mentioned or compression not given") exit() if re.search('.mp4',vid): print("Loading") else: exit() cap = cv2.VideoCapture(0) ret, frame = cap.read() def rescale_frame(frame, percent=75): width = int(frame.shape[1] * percent/ 100) height = int(frame.shape[0] * percent/ 100) dim = (width, height) return cv2.resize(frame, dim, interpolation =cv2.INTER_AREA) FPS= 15.0 FrameSize=(frame.shape[1], frame.shape[0]) fourcc = cv2.VideoWriter_fourcc(*'mp4v') out = cv2.VideoWriter('Video_output.mp4', fourcc, FPS, FrameSize, 0) while(cap.isOpened()): ret, frame = cap.read() # check for successfulness of cap.read() if not ret: break rescaled_frame=rescale_frame(frame,percent=compress) # Save the video out.write(rescaled_frame) cv2.imshow('frame',rescaled_frame) if cv2.waitKey(1) & 0xFF == ord('q'): break cap.release() out.release() cv2.destroyAllWindows()
1 回答
翻翻過去那場雪
TA貢獻2065條經驗 獲得超14個贊
問題是VideoWriter初始化。
您初始化了：
out = cv2.VideoWriter('Video_output.mp4', fourcc, FPS, FrameSize, 0)
最后一個參數的0意思是，isColor = False。您告訴我們，您要將幀轉換為灰度然后保存。但是您的代碼中沒有轉換。
此外，您還根據compress參數調整代碼中每個框架的大小。
如果我使用默認的壓縮參數：
cap = cv2.VideoCapture(0)
if cap.isOpened():
ret, frame = cap.read()
rescaled_frame = rescale_frame(frame)
(h, w) = rescaled_frame.shape[:2]
fourcc = cv2.VideoWriter_fourcc(*'mp4v')
writer = cv2.VideoWriter('Video_output.mp4',
fourcc, 15.0,
(w, h), True)
else:
print("Camera is not opened")
現在我們已經VideoWriter用所需的尺寸初始化了 。
完整代碼：
import time
import cv2
def rescale_frame(frame_input, percent=75):
width = int(frame_input.shape[1] * percent / 100)
height = int(frame_input.shape[0] * percent / 100)
dim = (width, height)
return cv2.resize(frame_input, dim, interpolation=cv2.INTER_AREA)
cap = cv2.VideoCapture(0)
if cap.isOpened():
ret, frame = cap.read()
rescaled_frame = rescale_frame(frame)
(h, w) = rescaled_frame.shape[:2]
fourcc = cv2.VideoWriter_fourcc(*'mp4v')
writer = cv2.VideoWriter('Video_output.mp4',
fourcc, 15.0,
(w, h), True)
else:
print("Camera is not opened")
while cap.isOpened():
ret, frame = cap.read()
rescaled_frame = rescale_frame(frame)
# write the output frame to file
writer.write(rescaled_frame)
cv2.imshow("Output", rescaled_frame)
key = cv2.waitKey(1) & 0xFF
if key == ord("q"):
break
cv2.destroyAllWindows()
cap.release()
writer.release()
可能的問題：我不想更改VideoWriter參數，該怎么辦？
答案：那么你需要將框架更改為灰色圖像：
while cap.isOpened():
# grab the frame from the video stream and resize it to have a
# maximum width of 300 pixels
ret, frame = cap.read()
frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
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