Monday, November 16, 2015

Opencv VideoCapture File, Web Camera, RTSP stream

Opencv VideoCapture File, Camera and stream

Opencv tutorial simple code in C++ to capture video from File, Ip camera stream and also the web camera plug into the computer.. The key is to have installed the FFMPEG espetially in case of reading the strem of IP cameras. In windows just use Opencv Installation by Nugets packages Here. Simple easy under 2 minutes instalation. In Linux you need to follow the instruction bellow. If you are on Debian Like package system. Under Fedora Red hat dist just use different aproach. Code is simple and installation is the key.. 

Windows use nugets packages
Linux you have to install and build Opencv With FFMPEG. Also simple. 

It is easy capture video in opencv

Video capture
 in opencv is really easy task, but for little bit experienced user. 

What is problem?
Problem is instalation of Opencv without recommended dependencies.

Just install all basic libs that is recommended on website.
# Basic packages
sudo apt-get -y install build-essential
sudo apt-get -y install cmake
sudo apt-get -y install pkg-config

# Basic dependencies
sudo apt-get -y install libgtk2.0-dev python-dev python-numpy

# OpenCV dependencies part II.
sudo apt-get -y install libgstreamer0.10-0-dbg libgstreamer0.10-0 libgstreamer0.10-dev libgstreamer-plugins-base0.10-dev libunicap2 libunicap2-dev libdc1394-22-dev libdc1394-22 libdc1394-utils libv4l-0 libv4l-dev

sudo apt-get -y install libavcodec-dev libavformat-dev libswscale-dev

sudo apt-get -y install libdc1394-22-dev libdc1394-utils

sudo apt-get -y install libjpeg-dev libpng-dev libtiff-dev libjasper-dev

sudo apt-get -y install libtiff5 libtiff5-dev
sudo apt-get -y install libopenexr-dev
sudo apt-get -y install libjasper-dev
# Algebra
sudo apt-get -y install libeigen3-dev

Install ffmpeg .

You need to download and build by own in case of Debian Jessie or some version of Ubuntu.
Just download, extract tar archive ffmpeg.tar.bz2.

1 configure instalation ./configure -- with Right Params.

2 Make - make -j4

3 install - make install

4 write config ldconfig -v

Compile opencv

Check this table during the opencv instalation. if you have FFMPEG and all AV libs 
AVCODEC AVFORMAT AVUTIL AVSWSCALE you can continue with opencv installation.
opencv config ffmpef
Opencv config

Read video file in Opencv

VideoCapture capture("input.mp4");

Read rtsp stream in Opencv

VideoCapture capture("rtsp://");
Some of my next post will be about rtsp stream format. PLS subscribe.

Read web camera in Opencv

VideoCapture capture(0);

Opencv 3 and higher c++ code


using namespace std;
using namespace cv;

//Chose input

//VideoCapture capture(0);
VideoCapture capture("rtsp://");
//VideoCapture capture("input.mp4");

// create mat to fill by external source
Mat frame;


       bool OK = capture.grab();

        if (OK == false){
        cout << "cannot grab" << endl;
          // retrieve a frame of your source
         // capture >> frame;


  1. Hi

    I can read the rtsp stream using opencv 3.1 (compiled with ffmpeg) in python. But after some time I start getting corrupted frames and after further time I get error while reading the frames. Have you encountered it? If it works fine for you maybe I should use the versions you are using.

  2. Problem is instalation of Opencv without recommended dependencies.web design tutorials

  3. Video capture
    in opencv is really easy task, but for little bit experienced user.



  4. The issues which are giving us trouble can be sorted out with the help of these cameras. dashcam review

  5. How do i capture an H264 frames with OpenCV and Python?


  6. How do i capture an H264 frames with OpenCV and Python?

    Thank You

  7. save some money (you don't have a webcam) you can convert your phone to an instant webcam with this amazing software.. Hikvision 8MP Cameras

  8. Hi! I would like to open a PAL camera using a frame grabber as interface between camera and software, What kind of path for videoCapture can i use? And what speficification do i have to use as input?
    Thanks a lot!

  9. This is genuinely an awesome read for me. I have bookmarked it and I am anticipating perusing new articles. Keep doing awesome!
    Web Development

  10. Its a great pleasure reading your post.Its full of information I am looking for and I love to post a comment that "The content of your post is awesome" Great work.


  11. Respecting the time and exertion you put into your site and point by point data you offer!..
    Web Development

  12. make any plugins to safeguard against hackers? I'm kinda paranoid about losing everything I've worked hard on. Any tips? Hikvision Dome Cameras

  13. I appreciate everything you have added to my knowledge base.Admiring the time and effort you put into your blog and detailed information you offer.Thanks. Best Camera Stabilizers

  14. Thanks for your post.
    I am facing error
    video_capture = cv2.VideoCapture(rtsp://
    after 100 or more than hundred frame video is freeze
    [h264 @ 0x204fedc0] error while decoding MB 41 1, bytestream -11