使用openCV在MAC上读取/写入avi视频 [英] read/write avi video on MAC using openCV

问题描述

我正在尝试在 MAC 10.6.8 上使用 openCV 2.4.0 读取 avi 视频并再次写入它，因为它没有任何更改

I am trying to read avi video and write it again as it is without any change using openCV 2.4.0 on MAC 10.6.8

我的视频是灰度的，frame_rate = 25，编解码器= 827737670，即FFV1(我想)

My videos is grayscale with frame_rate = 25 and Codec = 827737670 which is FFV1 (I guess)

问题是....当我按原样读写视频时....我看到尺寸和颜色发生了许多变化...经过3到4次写作，我可以看到视频开始变成(粉红色)彩色!!!

The problem is .... when I read and write the video as it is .... I see many changes in size and in color ... After 3 or 4 times of writing I can see the video start to be (Pink) color !!!

我不确定是什么问题！！！

I am not sure what is the problem !!!

这是我对感兴趣的人的代码

this is my code for the people who interest

提前感谢您的帮助:D

Appreciate your help in advance :D

Seereen

注意:我的计算机上装有FFMPEG V 0.11(我不知道这是否重要)

Note : I have on my computer FFMPEG V 0.11 (I do not know if this important)

{    

int main (int argc, char * const argv[]) {
    char name[50];

    if (argc==1)
    {
        printf("\nEnter the name of the video:");
        scanf("%s",name); 

    } else if (argc == 2)
        strcpy(name, argv[1]);

    else 
    {
        printf("To run this program you should enter the name of the program at least, or you can enter the name of the program then the file name");
        return 0; 
    }

    cvNamedWindow( "Read the video", CV_WINDOW_AUTOSIZE );

    // GET video
    CvCapture* capture = cvCreateFileCapture( name );
    if (!capture ) 
    {
        printf( "Unable to read input video." );
        return 0;
    }

    double fps = cvGetCaptureProperty( capture,CV_CAP_PROP_FPS);
     printf( "fps %f ",fps );
    int codec = cvGetCaptureProperty( capture,CV_CAP_PROP_FOURCC);
    printf( "codec %d ",codec );
    // Read frame
    IplImage* frame = cvQueryFrame( capture );
    // INIT the video writer
    CvVideoWriter *writer = cvCreateVideoWriter( "x7.avi", codec, fps, cvGetSize(frame),1);
    while(1) 
    {
        cvWriteFrame( writer, frame );
        cvShowImage( "Read the video", frame );
        // READ next frame
        frame = cvQueryFrame( capture );
        if( !frame ) 
            break;
        char c = cvWaitKey(33);
        if( c == 27 ) 
            break;
    }

    // CLEAN everything
    cvReleaseImage( &frame );
    cvReleaseCapture( &capture );
    cvReleaseVideoWriter( &writer );
    cvDestroyWindow( "Read the video" );    
    return 0;}

   } 

推荐答案

我找出了问题、、、、、以YUV240像素格式(为灰色)编写的原始视频

I figure out the problem ,,,,, The original videos written in YUV240 pixel format (and it is gray)

默认情况下，openCV在BGR上读取视频，因此每次我读取openCV时，openCV都会将像素值转换为BGR

the openCV read the video on BGR by default , so each time when I read it the openCV convert the pixel values to BGR

经过几次读写后，错误开始更大(因为转换操作)那为什么像素值会改变.....我看到视频是粉红色的！

after few time of reading and writing , the error start to be bigger (because the conversion operation) that why the pixels values change .....and I see the video pink !

解决方案是通过FFMPEG项目读取和编写此类视频，并提供YUV240和许多其他格式FFMPEG教程中有代码可以执行此操作

The Solution is , read and write this kind of videos by FFMPEG project which provide YUV240 and many other format there is a code can do this operation in the tutorial of FFMPEG

我希望这可以帮助遇到类似问题的其他人

I hope this can help the others who face similar problem

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