Take image from ip camera - c++

Question

I want to take images from my IP camera. I work in visual studio 2012.
At first, I've used openCV to connect to it. Here is my code.
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/core/core.hpp"
#include "opencv2/opencv.hpp"
int main()
{
cv::VideoCapture vcap;
const std::string videoStreamAddress = "rtsp://admin:admin#192.168.0.120/snl/live/1/1/stream1.cgi";
if (!vcap.open(videoStreamAddress))
{
printf("camera is null\n");
return -1;
}
else
{
cv::Mat image;
cv::namedWindow("Video", CV_WINDOW_AUTOSIZE);
while(1)
{
vcap >> image;
imshow("Video", image);
if(cv::waitKey(10) == 99 ) break;
}
}
cv::waitKey(1000);
return 0;
}
It shows the stream. But some of its images have distortion. I think it is because of decoding error. The error is this:
[h264 # 00decfe0] error while decoding MB 37 22, bytestream <td>
To solve this error I write another code inspired from http://answers.opencv.org/question/65932/how-to-stream-h264-video-with-rtsp-in-opencv-partially-answered/ . It uses libVLC to get the stream. here is my second code.
#include "opencv2/opencv.hpp"
#include "vlc/libvlc.h"
#include "vlc/libvlc_media.h"
#include "vlc/libvlc_media_player.h"
#include "ctime"
#include "Windows.h"
#include "string"
struct ctx
{
IplImage* image;
HANDLE mutex;
uchar* pixels;
};
void *lock(void *data, void**p_pixels)
{
struct ctx *ctx = (struct ctx*)data;
WaitForSingleObject(ctx->mutex, INFINITE);
*p_pixels = ctx->pixels;
return NULL;
}
void display(void *data, void *id){
(void) data;
assert(id == NULL);
}
void unlock(void *data, void *id, void *const *p_pixels){
struct ctx *ctx = (struct ctx*)data;
/* VLC just rendered the video, but we can also render stuff */
uchar *pixels = (uchar*)*p_pixels;
cvShowImage("image", ctx->image);
ReleaseMutex(ctx->mutex);
assert(id == NULL); /* picture identifier, not needed here */
}
int main()
{
// VLC pointers
libvlc_instance_t *vlcInstance;
libvlc_media_player_t *mp;
libvlc_media_t *media;
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=2", // Be much more verbose then normal for debugging purpose
};
vlcInstance = libvlc_new(sizeof(vlc_args) / sizeof(vlc_args[0]), vlc_args);
media = libvlc_media_new_location(vlcInstance, "rtsp://admin:admin#192.168.21.120/snl/live/1/1/stream1.cgi");
mp = libvlc_media_player_new_from_media(media);
libvlc_media_release(media);
context->mutex = CreateMutex(NULL, FALSE, NULL);
context->image = new Mat(VIDEO_HEIGHT, VIDEO_WIDTH, CV_8UC3);
context->pixels = (unsigned char *)context->image->data;
// show blank image
imshow("test", *context->image);
libvlc_video_set_callbacks(mp, lock, unlock, display, context);
libvlc_video_set_format(mp, "RV24", VIDEO_WIDTH, VIDEO_HEIGHT, VIDEO_WIDTH * 24 / 8); // pitch = width * BitsPerPixel / 8
int ii = 0;
int key = 0;
while(key != 27)
{
ii++;
if (ii > 5)
{
libvlc_media_player_play(mp);
}
float fps = libvlc_media_player_get_fps(mp);
//printf("fps:%f\r\n",fps);
key = waitKey(100); // wait 100ms for Esc key
}
libvlc_media_player_stop(mp);
return 0;
}
But it has nearly the same error. Some pixels losts and images has distortion.
[h264 # 02a3b660] Frame num gap 6 4
[h264 # 02a42220] no picture oooo
How Can I fix this problem? The problem rooted from my code and the using libraries or my camera?

Answer 1

im working on some project like you,this error is because openCVcant deal with H264 , i suggest you use VLC library as mentioned in here,and cause you use VS2012 you can use VLCDotNetin your project.other options is FFmpeg,aforgethat are compatible with H264.