video.release()是有什么功能
时间: 2023-02-26 19:48:56 浏览: 39
`video.release()` 是一个在视频处理库中的函数,主要用于释放摄像头或者视频文件占用的系统资源。当您完成对视频的处理后,如果不调用 `video.release()` 函数,这些资源将不会释放,会对系统产生负担,同时也可能影响其他视频处理的任务。因此,使用完视频后一定要调用 `video.release()` 来释放视频占用的系统资源。
相关问题
import cv2 # 定义阈值(相似度百分比) threshold = 90 # 加载存储在闪存中的视频码流 flash_video = cv2.VideoCapture('path/to/flash_video.mp4') # 加载接收到的视频码流 received_video = cv2.VideoCapture('path/to/received_video.mp4') # 检查视频是否成功打开 if not flash_video.isOpened() or not received_video.isOpened(): print("无法打开视频文件") exit() frame_count = min(flash_video.get(cv2.CAP_PROP_FRAME_COUNT), received_video.get(cv2.CAP_PROP_FRAME_COUNT)) match_count = 0 for i in range(int(frame_count)): # 从闪存视频和接收到的视频中读取帧 ret_flash, frame_flash = flash_video.read() ret_received, frame_received = received_video.read() if not ret_flash or not ret_received: print("视频读取错误") break # 将帧转换为灰度图像进行比较 gray_flash = cv2.cvtColor(frame_flash, cv2.COLOR_BGR2GRAY) gray_received = cv2.cvtColor(frame_received, cv2.COLOR_BGR2GRAY) # 使用均方差计算帧之间的相似度 mse = ((gray_flash - gray_received) ** 2).mean() # 计算相似度百分比 similarity = (1 - mse / 255) * 100 # 判断帧是否相似 if similarity >= threshold: match_count += 1 # 计算相似度百分比 match_percentage = match_count / frame_count * 100 # 判断是否通过 if match_percentage >= threshold: print("通过") else: print("失败") # 释放资源 flash_video.release() received_video.release() 请将这段程序用C语言实现
以下是将上述Python代码转换为C语言的示例实现:
```c
#include <stdio.h>
#include <stdlib.h>
#include <opencv2/opencv.hpp>
#define THRESHOLD 90.0
int main() {
cv::VideoCapture flashVideo("path/to/flash_video.mp4");
cv::VideoCapture receivedVideo("path/to/received_video.mp4");
if (!flashVideo.isOpened() || !receivedVideo.isOpened()) {
printf("无法打开视频文件\n");
return -1;
}
double frameCount = std::min(flashVideo.get(cv::CAP_PROP_FRAME_COUNT), receivedVideo.get(cv::CAP_PROP_FRAME_COUNT));
int matchCount = 0;
for (int i = 0; i < frameCount; i++) {
cv::Mat frameFlash, frameReceived;
bool retFlash = flashVideo.read(frameFlash);
bool retReceived = receivedVideo.read(frameReceived);
if (!retFlash || !retReceived) {
printf("视频读取错误\n");
break;
}
cv::Mat grayFlash, grayReceived;
cv::cvtColor(frameFlash, grayFlash, cv::COLOR_BGR2GRAY);
cv::cvtColor(frameReceived, grayReceived, cv::COLOR_BGR2GRAY);
cv::Mat diff;
cv::absdiff(grayFlash, grayReceived, diff);
cv::Scalar mse = cv::mean(diff.mul(diff));
double similarity = (1.0 - mse.val[0] / 255.0) * 100.0;
if (similarity >= THRESHOLD) {
matchCount++;
}
}
double matchPercentage = matchCount / frameCount * 100.0;
if (matchPercentage >= THRESHOLD) {
printf("通过\n");
} else {
printf("失败\n");
}
flashVideo.release();
receivedVideo.release();
return 0;
}
```
请确保已经安装了OpenCV库,并根据你的环境进行必要的配置和链接。此示例代码将使用OpenCV库进行视频读取、图像处理和比较,实现了与Python代码相同的功能。如果需要进一步优化和适配,你可以根据自己的需求进行修改。希望对你有所帮助!
import time from serial import Serial import serial.tools.list_ports import cv2 import numpy as np cap1=cv2.VideoCapture("/Users/yankaipan/Desktop/stand.mp4") cap2=cv2.VideoCapture("/Users/yankaipan/Desktop/apple.mp4") cap3=cv2.VideoCapture("/Users/yankaipan/Desktop/bamboo.mp4") cap4=cv2.VideoCapture("/Users/yankaipan/Desktop/rubbish.mp4") port_list = list(serial.tools.list_ports.comports()) port_list_1 =list(port_list[2]) port_serial = port_list_1[0] arduinoData=serial.Serial(port_serial,9600) time.sleep(1) current_video=None #记录当前正在播放的视频 while True: while (arduinoData.inWaiting()==0): pass dataPacket=arduinoData.readline() dataPacket=dataPacket.decode().strip() print(dataPacket) time.sleep(3) # if dataPacket=="b": # print("1") # else: # print('2') if dataPacket=="a": if current_video!=cap1: #判断是否需要切换视频 if current_video is not None: current_video.release() current_video=cap1 while(cap1.isOpened()): ret, frame = cap1.read() if ret == True: cv2.imshow('Frame', frame) if cv2.waitKey(25) & 0xFF == ord('q'): break else: cap1.set(cv2.CAP_PROP_POS_FRAMES,0) current_video.set(cv2.CAP_PROP_FRAMES,0) elif dataPacket=="b": if current_video!=cap2: #判断是否需要切换视频 if current_video is not None: current_video.release() current_video=cap2 while(cap2.isOpened()): ret, frame = cap2.read() if ret == True: cv2.imshow('Frame', frame) if cv2.waitKey(25) & 0xFF == ord('q'): break else: #cap2.set(cv2.CAP_PROP_POS_FRAMES,0) current_video.set(cv2.CAP_PROP_FRAMES,0) elif dataPacket=="c": if current_video!=cap3: #判断是否需要切换视频 if current_video is not None: current_video.release() current_video=cap3 while(cap3.isOpened()): ret, frame = cap3.read() if ret == True: cv2.imshow('Frame', frame) if cv2.waitKey(25) & 0xFF == ord('q'): break else: #cap3.set(cv2.CAP_PROP_POS_FRAMES,0) current_video.set(cv2.CAP_PROP_FRAMES,0) elif dataPacket=="d": if current_video!=cap4: #判断是否需要切换视频 if current_video is not None: current_video.release() current_video=cap4 while(cap4.isOpened()): ret, frame = cap4.read() if ret == True: cv2.imshow('Frame', frame) if cv2.waitKey(25) & 0xFF == ord('q'): break else: #cap4.set(cv2.CAP_PROP_POS_FRAMES,0) current_video.set(cv2.CAP_PROP_FRAMES,0) cv2.destroyAllWindows()代码运行播放a视频时接收到其他b或c或d;并不能播放相应的视频,该怎样修改代码才能让代码运行时实现这一功能?
在你的代码中,当收到指令时,会先判断当前播放的视频是不是需要切换的视频,如果是则释放当前视频,播放新的视频。但是在播放新的视频时,你使用了一个 while 循环读取视频帧并显示,这个循环是不会退出的,直到视频播放完毕或者用户按下 'q' 键退出。因此,即使收到了其他指令,也无法立即停止当前的视频播放。
为了解决这个问题,你可以在收到新指令时,先将当前正在播放的视频暂停或者停止,然后释放视频资源,最后根据接收到的指令切换到相应的视频,并开始播放新的视频。下面是修改后的代码:
```
import time
from serial import Serial
import serial.tools.list_ports
import cv2
import numpy as np
cap1 = cv2.VideoCapture("/Users/yankaipan/Desktop/stand.mp4")
cap2 = cv2.VideoCapture("/Users/yankaipan/Desktop/apple.mp4")
cap3 = cv2.VideoCapture("/Users/yankaipan/Desktop/bamboo.mp4")
cap4 = cv2.VideoCapture("/Users/yankaipan/Desktop/rubbish.mp4")
port_list = list(serial.tools.list_ports.comports())
port_list_1 = list(port_list[2])
port_serial = port_list_1[0]
arduinoData = serial.Serial(port_serial, 9600)
time.sleep(1)
current_video = None # 记录当前正在播放的视频
while True:
while (arduinoData.inWaiting() == 0):
pass
dataPacket = arduinoData.readline()
dataPacket = dataPacket.decode().strip()
print(dataPacket)
time.sleep(3)
# 停止当前视频的播放
if current_video is not None:
current_video.release()
# 切换到新的视频
if dataPacket == "a":
current_video = cap1
elif dataPacket == "b":
current_video = cap2
elif dataPacket == "c":
current_video = cap3
elif dataPacket == "d":
current_video = cap4
# 开始播放新的视频
if current_video is not None:
current_video.set(cv2.CAP_PROP_POS_FRAMES, 0) # 将视频设置为第一帧
while (current_video.isOpened()):
ret, frame = current_video.read()
if ret == True:
cv2.imshow('Frame', frame)
if cv2.waitKey(25) & 0xFF == ord('q'):
break
else:
current_video.set(cv2.CAP_PROP_POS_FRAMES, 0)
cv2.destroyAllWindows()
```
在修改后的代码中,当收到新指令时,会先停止当前视频的播放,并释放资源。然后根据指令选择新的视频并开始播放。在播放新的视频时,每次读取一帧并显示,如果用户按下 'q' 键,则退出循环停止视频播放。