OpenCV:读取视频序列

本文介绍了OpenCV:读取视频序列的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

是否有一种在OpenCV中随机读取视频帧的方法?就像使用索引访问数组一样?否则，如果我想在CPU或GPU中加载完整的视频，该怎么办?

Is there a way of randomly reading video frames in OpenCV....just like arrays are accessed using indexes? Otherwise, if I want to load complete video in CPU or GPU how can I do it?

推荐答案

您可以在视频捕获中使用set(int propId, double value)方法(另请参阅文档)，其中propId可以是以下之一:

You can use the set(int propId, double value) method on your video capture (also check out the documentation), where propId can either be one of the following:

CV_CAP_PROP_POS_MSEC:视频文件的当前位置，以毫秒为单位.
CV_CAP_PROP_POS_FRAMES:接下来要解码/捕获的帧的从0开始的索引.
CV_CAP_PROP_POS_AVI_RATIO:视频文件的相对位置:0-电影的开始，1-电影的结束.

CV_CAP_PROP_POS_MSEC: Current position of the video file in milliseconds.
CV_CAP_PROP_POS_FRAMES: 0-based index of the frame to be decoded/captured next.
CV_CAP_PROP_POS_AVI_RATIO: Relative position of the video file: 0 - start of the film, 1 - end of the film.

一个播放视频50秒的小例子:

A small example that plays a video 50 seconds in:

int main( int argc, char **argv )
{
    namedWindow("Frame", CV_WINDOW_NORMAL);
    Mat frame;

    VideoCapture capture(argv[1]);
    if (!capture.isOpened())
    {
        //error in opening the video input
        cerr << "Unable to open video file: " << argv[1] << endl;
        exit(EXIT_FAILURE);
    }

    capture.set(CV_CAP_PROP_POS_MSEC, 50000);
    for (;;)
    {
        //read the current frame
        if (!capture.read(frame))
        {
            cerr << "Unable to read next frame." << endl;
            cerr << "Exiting program!" << endl;
            exit(EXIT_FAILURE);
        }
        imshow("Frame", frame);
        waitKey(20);
    }
}

这篇关于OpenCV:读取视频序列的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！

film