YOLOv3使用笔记——保存检测视频结果

https://github.com/RongSong1993/YOLOv3_SaveVideo

1.测试视频主要是调用到detector demo，主要修改的是demo.c中的demo函数。

./darknet detector demo ./cfg/voc.data ./cfg/yolov3-voc.cfg ./results/yolov3-voc_final.weights 1.mp4 -gpus 0,1

在image.c中定义视频保存函数

void save_video(image p, CvVideoWriter *mVideoWriter)
{
    image copy = copy_image(p);
    if(p.c == 3) rgbgr_image(copy);
    int x,y,k;

    IplImage *disp = cvCreateImage(cvSize(p.w,p.h), IPL_DEPTH_8U, p.c);
    int step = disp->widthStep;
    for(y = 0; y < p.h; ++y){
        for(x = 0; x < p.w; ++x){
            for(k= 0; k < p.c; ++k){
                disp->imageData[y*step + x*p.c + k] = (unsigned char)(get_pixel(copy,x,y,k)*255);
            }
        }
    }
    cvWriteFrame(mVideoWriter,disp);
    cvReleaseImage(&disp);
    free_image(copy);
}

修改demo.c

定义

#define DEMO 1

#define SAVEVIDEO

#ifdef OPENCV

#ifdef SAVEVIDEO
   static CvVideoWriter *mVideoWriter;
#endif

void demo(char *cfgfile, char *weightfile, float thresh, int cam_index, const char *filename, char **names, int classes, int delay, char *prefix, int avg_frames, float hier, int w, int h, int frames, int fullscreen)
{
    //demo_frame = avg_frames;
    image **alphabet = load_alphabet();
    demo_names = names;
    demo_alphabet = alphabet;
    demo_classes = classes;
    demo_thresh = thresh;
    demo_hier = hier;
    printf("Demo\n");
    net = load_network(cfgfile, weightfile, 0);
    set_batch_network(net, 1);
    pthread_t detect_thread;
    pthread_t fetch_thread;

    srand(2222222);

    int i;
    demo_total = size_network(net);
    predictions = calloc(demo_frame, sizeof(float*));
    for (i = 0; i < demo_frame; ++i){
        predictions[i] = calloc(demo_total, sizeof(float));
    }
    avg = calloc(demo_total, sizeof(float));

    if(filename){
        printf("video file: %s\n", filename);
        cap = cvCaptureFromFile(filename);
    #ifdef SAVEVIDEO
        if(cap){
            //int mfps = cvGetCaptureProperty(cap,CV_CAP_PROP_FPS);   //local video file，needn't change
 	    int mfps = 200;
            mVideoWriter=cvCreateVideoWriter("Output.avi",CV_FOURCC('M','J','P','G'),mfps,cvSize(cvGetCaptureProperty(cap,CV_CAP_PROP_FRAME_WIDTH),cvGetCaptureProperty(cap,CV_CAP_PROP_FRAME_HEIGHT)),1);
        }
    #endif
    }else{
        cap = cvCaptureFromCAM(cam_index);
    #ifdef SAVEVIDEO
        if(cap){
            //int mfps = cvGetCaptureProperty(cap,CV_CAP_PROP_FPS);  //webcam video file，need change.
            int mfps = 25;     //the output video FPS，you can set here.
            mVideoWriter=cvCreateVideoWriter("Output_webcam.avi",CV_FOURCC('M','J','P','G'),mfps,cvSize(cvGetCaptureProperty(cap,CV_CAP_PROP_FRAME_WIDTH),cvGetCaptureProperty(cap,CV_CAP_PROP_FRAME_HEIGHT)),1);
        }
    #endif
        if(w){
            cvSetCaptureProperty(cap, CV_CAP_PROP_FRAME_WIDTH, w);
        }
        if(h){
            cvSetCaptureProperty(cap, CV_CAP_PROP_FRAME_HEIGHT, h);
        }
        if(frames){
            cvSetCaptureProperty(cap, CV_CAP_PROP_FPS, frames);
        }
    }

    if(!cap) error("Couldn't connect to webcam.\n");

    buff[0] = get_image_from_stream(cap);
    buff[1] = copy_image(buff[0]);
    buff[2] = copy_image(buff[0]);
    buff_letter[0] = letterbox_image(buff[0], net->w, net->h);
    buff_letter[1] = letterbox_image(buff[0], net->w, net->h);
    buff_letter[2] = letterbox_image(buff[0], net->w, net->h);
    ipl = cvCreateImage(cvSize(buff[0].w,buff[0].h), IPL_DEPTH_8U, buff[0].c);

    int count = 0;
    if(!prefix){
        cvNamedWindow("Demo", CV_WINDOW_NORMAL); 
        if(fullscreen){
            cvSetWindowProperty("Demo", CV_WND_PROP_FULLSCREEN, CV_WINDOW_FULLSCREEN);
        } else {
            cvMoveWindow("Demo", 0, 0);
            cvResizeWindow("Demo", 1352, 1013);
        }
    }

    demo_time = what_time_is_it_now();

    while(!demo_done){
        buff_index = (buff_index + 1) %3;
        if(pthread_create(&fetch_thread, 0, fetch_in_thread, 0)) error("Thread creation failed");
        if(pthread_create(&detect_thread, 0, detect_in_thread, 0)) error("Thread creation failed");
        if(!prefix){
            #ifdef SAVEVIDEO
                save_video(buff[0],mVideoWriter);    
            #endif
            fps = 1./(what_time_is_it_now() - demo_time);
            demo_time = what_time_is_it_now();
            display_in_thread(0);
        }else{
            char name[256];
            sprintf(name, "%s_%08d", prefix, count);
            #ifdef SAVEVIDEO
                  save_video(buff[0],mVideoWriter);
            #else
            save_image(buff[(buff_index + 1)%3], name);
            #endif
        }
        pthread_join(fetch_thread, 0);
        pthread_join(detect_thread, 0);
        ++count;
    }
}

用来测试录像视频，其中mfps为保存的处理帧率，保存结果为Output.avi。

参考

https://blog.csdn.net/sinat_33718563/article/details/79964758