OpenCV IP camera application crashes [h264 @ 0xxxxx] missing picture in access unit

Question

I have an opencv application in cpp.

It captures video stream and saves it to video files with the simple constructs from opencv.

It works perfectly with my webcam.

But, it crashes maybe after about ten seconds, while I run it to capture the stream from IP Camara.

My compile command is:

g++ -O3 IP_Camera_linux.cpp -o IP_Camera `pkg-config --cflags --libs opencv`

My Stream from IP cam is accessed like this:

const string Stream = "rtsp://admin:[email protected]/";

It does run perfectly, shows video and saves it until the displayed video freezes and the application crashes. While the error message on the terminal is:

[h264 @ 0x15e6f60] error while decoding MB 59 31, bytestream (-20)
[h264 @ 0x15e8200] error while decoding MB 61 27, bytestream (-3)
[h264 @ 0x109c880] missing picture in access unit
[h264 @ 0x109c000] no frame!

To my understanding, the fist two lines in the above error message might have something to do but does not actually crash the application. The last two lines are probably the reasons or the cause?

Any help?

Answer 1

Got the solution after lots of hit and trial. Just changed the stream address a bit and it worked.

From:

const string Stream = "rtsp://admin:[email protected]/";

To:

const string Stream = "rtsp://admin:[email protected]/ch1-s1?tcp";

NO idea, what change it did make?

BUT IT WORKS PERFECTLY!!!

Even the pervasive warnings of the form:

[h264 @ 0x15e6f60] error while decoding MB 59 31, bytestream (-20)
[h264 @ 0x15e8200] error while decoding MB 61 27, bytestream (-3) 

are gone.

Anyways would appreciate if some one could explain it with the logical reason behind.

CREDIT

Answer 2

It is an error from ffmpeg. Probably your ffmpeg is old version and you may want to update it. It solved the problem perfectly for my case by reinstalling the latest opencv and ffmpeg as follows:

• Install latest ffmpeg

  git clone git://source.ffmpeg.org/ffmpeg.git
  cd ffmpeg 
  ./configure --enable-shared --disable-static 
  make 
  sudo make install
  

• Install the latest opencv

  git clone [email protected]:opencv/opencv.git
  cd opencv
  mkdir build
  cd build 
  cmake ../ -DCMAKE_BUILD_TYPE=Release
  make
  sudo make install
  

Answer 3

As a citation to the original answer, adding ?tcp to the end forces the rtsp connection to run using the tcp protocol instead of the udp protocol which is useful if you do not actively check for any connection problem and therefore you can't afford to have any packet loss.

For robust running you can check for NULL image in you loop and if you get a NULL image, you can reset the camera connection:

IplImage *img = cvQueryFrame(camera);
        if (img == NULL) {
            printf("img == null ");
            fflush(stdout);
            camera = cvCreateFileCapture("rtsp://admin:[email protected]/ch1-s1?tcp");
        }