Open mp4 with libVLC and play it in OpenCV C++ - c++

Question

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:
main error: open of `5.mp4' failed
main error: Your input can't be opened
main error: VLC is unable to open the MRL '5.mp4'. Check the log for details.
Here's my code:
#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);
}
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.
EDIT:
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
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

Answer 1

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.