使用libVLC打开mp4并在OpenCV C ++中播放 [英] Open mp4 with libVLC and play it in OpenCV C++

问题描述

我想播放我使用libVLC和OpenCV从IP摄像机(H264编解码器)获得的视频文件，因此我从

I want to play video file, that i obtained from IP-camera (H264-codec) using libVLC and OpenCV, so i took the code from this post, then created project in VS 2010, and put my mp4 file into project folder ("5.mp4"). When i started it - i got this errors:

主要错误:打开"5.mp4"失败

main error: open of `5.mp4' failed

主要错误:您的输入无法打开

main error: Your input can't be opened

主要错误:VLC无法打开MRL'5.mp4'.查看日志以获取详细信息.

main error: VLC is unable to open the MRL '5.mp4'. Check the log for details.

这是我的代码:

#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);
}

我想这很容易解决，但是我在互联网上找不到任何信息.我也尝试将其放入"C:\ 5.mp4"，但出现相同的错误.感谢您的帮助.

I guess, that is easy to fix, but i could't find any information at the Internet. I also tryied to put it into "C:\5.mp4", but i got the same errors. Thanks for any help.

好的，所以我解决了这个问题，我需要将 file:///放在"5.mp4"之前，现在我的视频正在播放，但是看起来像这样:

Ok, so i fixed this issue, i need to put file:/// before "5.mp4", now my video is playing, but it looks like this:

EDIT02 好的，有了"* .avi"，一切看起来都很好，所以我猜这个文件有问题-我使用VLC将其记录在IP摄像机中，并保存到* .mp4

EDIT02 Ok, with "*.avi" everything looks good, so i guess problem with this file - i recorded it frop IP-camera, using VLC, and saved it into *.mp4

推荐答案

好，所以我发现了问题，我在视频分辨率上犯了一个错误，原始分辨率为2560x1536，所以当我放libvlc_video_set_format(mp,2560,1536,2560 *3);时，我的图片看起来不错，因此，在将其传递给OpenCV之后，我可以调整其大小.

Ok, so i found the problem, i made a mistake with video resolution, original resolution is 2560x1536, so when i put libvlc_video_set_format(mp,2560,1536,2560 *3); my picture looks fine, so after i pass it to OpenCV i could resize it.

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