使用libVLC打開mp4並在OpenCV C ++中播放

Question

我想播放我使用libVLC和OpenCV從IP攝像機（H264編解碼器）獲得的視頻文件，因此我從這篇文章中獲取了代碼，然后在VS 2010中創建了項目，並將mp4文件放入項目文件夾（ 5.mp4“）。 當我啟動它時-我得到了這個錯誤：

主要錯誤：打開“ 5.mp4”失敗

主要錯誤：您的輸入無法打開

主要錯誤：VLC無法打開MRL'5.mp4'。 檢查日志以獲取詳細信息。

這是我的代碼：

#include <vlc/vlc.h>
#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <stdio.h>

using namespace cv; 
using namespace std;

struct VideoDataStruct {
  int param;
};

int done = 0;
libvlc_media_player_t *mp;
unsigned int videoBufferSize = 0;
uint8_t *videoBuffer = 0;

 void cbVideoPrerender(void *p_video_data, uint8_t **pp_pixel_buffer, int size) {
// Locking
  if (size > videoBufferSize || !videoBuffer)
  {
    printf("Reallocate raw video buffer\n");
    free(videoBuffer);
    videoBuffer = (uint8_t *) malloc(size);
    videoBufferSize = size;
  }

   *pp_pixel_buffer = videoBuffer;
}  

 void cbVideoPostrender(void *p_video_data, uint8_t *p_pixel_buffer, int width, int height, int pixel_pitch, int size, int64_t pts) {
     // Unlocking
     //CloseHandle(hMutex);
 }

 static void handleEvent(const libvlc_event_t* pEvt, void* pUserData) {
   libvlc_time_t time;
   switch(pEvt->type)
   {
      case libvlc_MediaPlayerTimeChanged:
          time = libvlc_media_player_get_time(mp);
          printf("MediaPlayerTimeChanged %lld ms\n", (long long)time);
          break;
      case libvlc_MediaPlayerEndReached:
          printf ("MediaPlayerEndReached\n");
          done = 1;
        break;
       default:
          printf("%s\n", libvlc_event_type_name(pEvt->type));
    }
}

int main(int argc, char* argv[]) {

// VLC pointers 
libvlc_instance_t *inst;
libvlc_media_t *m;
void *pUserData = 0;
VideoDataStruct dataStruct;

// VLC options
char smem_options[1000];
// RV24
sprintf(smem_options
    , "#transcode{vcodec=RV24}:smem{"
     "video-prerender-callback=%lld,"
     "video-postrender-callback=%lld,"
     "video-data=%lld,"
     "no-time-sync},"
    , (long long int)(intptr_t)(void*)&cbVideoPrerender
    , (long long int)(intptr_t)(void*)&cbVideoPostrender
    , (long long int)(intptr_t)(void*)&dataStruct
);

const char * const vlc_args[] = {
          "-I", "dummy",            // Don't use any interface
          "--ignore-config",        // Don't use VLC's config
          "--extraintf=logger",     // Log anything
          "--verbose=1",            // Be verbose
          "--sout", smem_options    // Stream to memory
           };

// We launch VLC
inst = libvlc_new(sizeof(vlc_args) / sizeof(vlc_args[0]), vlc_args);

/* Create a new item */
m = libvlc_media_new_location(inst, "5.mp4");

/* Create a media player playing environement */
mp = libvlc_media_player_new_from_media (m);

libvlc_event_manager_t* eventManager = libvlc_media_player_event_manager(mp);
libvlc_event_attach(eventManager, libvlc_MediaPlayerTimeChanged, handleEvent, pUserData);
libvlc_event_attach(eventManager, libvlc_MediaPlayerEndReached, handleEvent, pUserData);
libvlc_event_attach(eventManager, libvlc_MediaPlayerPositionChanged, handleEvent, pUserData);

libvlc_video_set_format(mp, "RV24", 1280, 720, 1280* 3 );

/* play the media_player */
libvlc_media_player_play (mp);

 while(1)
 {
     if(videoBuffer)            // Check for invalid input
     {
         // CV_8UC3 = 8 bits, 3 chanels
         Mat img = Mat(Size(1280, 720), CV_8UC3, videoBuffer);
         // cvtColor(img, img, CV_RGB2BGR);
         namedWindow("Display window", WINDOW_AUTOSIZE);    // Create a window for display.
         imshow("Display window", img);     // Show our image inside it.
     }
 }
 libvlc_release (inst);
}

我想這很容易解決，但是我在互聯網上找不到任何信息。 我也嘗試將其放入“ C：\\ 5.mp4”，但出現相同的錯誤。 謝謝你的幫助。

編輯：好的，所以我解決了這個問題，我需要將file：///放在“ 5.mp4”之前，現在我的視頻正在播放，但是看起來像這樣：

EDIT02好吧，有了“ * .avi”，一切看起來都不錯，所以我猜這個文件有問題-我使用VLC將其記錄在IP攝像機中，並保存到* .mp4中

Answer 1

好的，所以我發現了問題，我在視頻分辨率上犯了一個錯誤，原始分辨率為2560x1536，所以當我放libvlc_video_set_format(mp,2560,1536,2560 *3); 我的圖片看起來不錯，因此在將其傳遞給OpenCV之后，可以調整其大小。