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• use ffmpeg encode a video in android

  18 août 2014, par user2098010

  i followed below link for using ffmpeg in android
  http://www.roman10.net/how-to-build-ffmpeg-with-ndk-r9/

  and done ! ndk-build

  i need to encode a video captured by phone camera for slow down

  i’ve using sample file in ffmpeg/sample...
  but i can’t get encoded a video(slow down)

  output video has 1sec playtime.
  few color are displayed !

  plz... help me

  i wanna sleep well...

    AVCodec *codec;
  
      AVCodecContext *c= NULL;
  
      int i, ret, x, y, got_output;
  
      FILE *f;
  
      AVFrame *frame;
  
      AVPacket pkt;
  
      uint8_t endcode[] = { 0, 0, 1, 0xb7 };
  
  
  
          __android_log_print(ANDROID_LOG_DEBUG, "BASEBALL", "%s",filename);
  
  
  
      /* find the mpeg1 video encoder */
  
      codec = avcodec_find_encoder(CODEC_ID_H263);
  
      if (!codec) {
  
          __android_log_print(ANDROID_LOG_DEBUG, "BASEBALL", "Codec not found");
  
          exit(1);
  
      }
  
  
  
      c = avcodec_alloc_context3(codec);
  
      if (!c) {
  
          __android_log_print(ANDROID_LOG_DEBUG, "BASEBALL", "Could not allocate video codec context");
  
          exit(1);
  
      }
  
  
  
      /* put sample parameters */
  
      c->bit_rate = 400000;
  
      /* resolution must be a multiple of two */
  
      c->width = 352;
  
      c->height = 288;
  
      /* frames per second */
  
      c->time_base= (AVRational){1,25};
  
      c->gop_size = 10; /* emit one intra frame every ten frames */
  
      c->pix_fmt = AV_PIX_FMT_YUV420P;
  
  
  
  
  
     // if(codec == AV_CODEC_ID_H264)
  
        // av_opt_set(c->priv_data, "preset", "slow", 0);
  
  
  
      /* open it */
  
      if (avcodec_open2(c, codec, NULL) < 0) {
  
          __android_log_print(ANDROID_LOG_DEBUG, "BASEBALL", "Could not open codec");
  
          exit(1);
  
      }
  
  
  
      f = fopen(filename, "wb");
  
      if (f == NULL) {
  
          __android_log_print(ANDROID_LOG_DEBUG, "BASEBALL", "Could not open");
  
          exit(1);
  
      }
  
  
  
      frame = avcodec_alloc_frame();
  
      if (!frame) {
  
          __android_log_print(ANDROID_LOG_DEBUG, "BASEBALL", "Could not allocate video frame");
  
          exit(1);
  
      }
  
      frame->format = c->pix_fmt;
  
      frame->width  = c->width;
  
      frame->height = c->height;
  
  
  
      /* the image can be allocated by any means and av_image_alloc() is
  
       * just the most convenient way if av_malloc() is to be used */
  
      ret = av_image_alloc(frame->data, frame->linesize, c->width, c->height,
  
                           c->pix_fmt, 32);
  
      if (ret < 0) {
  
          __android_log_print(ANDROID_LOG_DEBUG, "BASEBALL", "Could not allocate raw picture buffer");
  
          exit(1);
  
      }
  
  
  
      /* encode 1 second of video */
  
      for(i=0;i<250;i++) {
  
          av_init_packet(&pkt);
  
          pkt.data = NULL;    // packet data will be allocated by the encoder
  
          pkt.size = 0;
  
  
  
          fflush(stdout);
  
          /* prepare a dummy image */
  
          /* Y */
  
          for(y=0;yheight;y++) {
  
              for(x=0;xwidth;x++) {
  
                  frame->data[0][y * frame->linesize[0] + x] = x + y + i * 3;
  
              }
  
          }
  
  
  
          /* Cb and Cr */
  
          for(y=0;yheight/2;y++) {
  
              for(x=0;xwidth/2;x++) {
  
                  frame->data[1][y * frame->linesize[1] + x] = 128 + y + i * 2;
  
                  frame->data[2][y * frame->linesize[2] + x] = 64 + x + i * 5;
  
              }
  
          }
  
  
  
          frame->pts = i;
  
  
  
          /* encode the image */
  
          ret = avcodec_encode_video2(c, &pkt, frame, &got_output);
  
          if (ret < 0) {
  
              __android_log_print(ANDROID_LOG_DEBUG, "BASEBALL", "Error encoding frame");
  
              exit(1);
  
          }
  
  
  
          if (got_output) {
  
              __android_log_print(ANDROID_LOG_DEBUG, "BASEBALL", "encode the image Write frame pktsize  %d", pkt.size);
  
              fwrite(pkt.data, 1, pkt.size, f);
  
              av_free_packet(&pkt);
  
          }
  
      }
  
  
  
      /* get the delayed frames */
  
      for (got_output = 1; got_output; i++) {
  
          fflush(stdout);
  
  
  
          ret = avcodec_encode_video2(c, &pkt, NULL, &got_output);
  
          if (ret < 0) {
  
              __android_log_print(ANDROID_LOG_DEBUG, "BASEBALL", "Error encoding frame");
  
              fprintf(stderr, "Error encoding frame\n");
  
              exit(1);
  
          }
  
  
  
          if (got_output) {
  
              __android_log_print(ANDROID_LOG_DEBUG, "BASEBALL", "get the delayed frames Write frame pktsize  %d", pkt.size);
  
              fwrite(pkt.data, 1, pkt.size, f);
  
              av_free_packet(&pkt);
  
          }
  
      }
  
  
  
      /* add sequence end code to have a real mpeg file */
  
      fwrite(endcode, 1, sizeof(endcode), f);
  
      fclose(f);
  
  
  
      avcodec_close(c);
  
      av_free(c);
  
      av_freep(&frame->data[0]);
  
      avcodec_free_frame(&frame);

• Ode to the Gravis Ultrasound

  1er août 2011, par Multimedia Mike — General

  WARNING : This post is a bunch of nostalgia. Feel free to follow along if you recall the DOS days of the early-mid 1990s.

  I finally let go of my Gravis Ultrasound MAX sound card a little while ago. It felt like the end of an era for me, even though I had scarcely used the card in recent memory.

  
  
  

  The Beginning
  What is the Gravis Ultrasound ? Only the finest PC sound card from the classic DOS days. Back in the day (very early 1990s), most consumer PC sound cards were Yamaha OPL FM synthesizers paired with a basic digital to analog converter (DAC). Gravis, a company known for game controllers, dared to break with the dominant paradigm of Sound Blaster clones and create a sound card that had 32 digital channels.
  
  I heard about the GUS sometime in 1992 through one of the dominant online services at the time, Prodigy. Through the message boards, I learned of a promotion with Electronic Arts in which customers could pre-order a GUS at a certain discount along with 2 EA games from a selected catalog (with progressive discounts when ordering more games from the list). I know I got the DOS version of PowerMonger ; I think the other was Night Shift, though that doesn’t seem to be an EA title.

  Anyway, 1992 saw many maddening delays of the GUS hardware. Finally, reports of GUS shipments began to trickle into the Prodigy message forums. Then one day in November, 1992, mine arrived. Into the 286 machine it went and a valiant attempt at software installation was made. A friend and I fought with the software late into the evening, trying to make this thing work reasonably. I remember grabbing a pair of old headphones sitting near the computer that were used for an ancient (even for the time) portable radio. That was the only means of sound reproduction we had available at that moment. And it still sounded incredible.

  After graduating to progressively superior headphones, I would later return to that original pair only to feel my ears were being physically assaulted. Strange, they sounded fine that first night I was trying to make the GUS work. I guess this was my first understanding that the degree to which one is a snobby audiophile is all a matter of hard-earned experience.

  Technology
  The GUS was powered by something called a GF1 which was supposed to use a technology called wavetable synthesis. In the early days, I thought (and I wasn’t alone in this) that this meant that the GF1 chip had a bunch of digitized instrument samples stored in the ASIC. That wasn’t it.

  However, it did feature 32 digital channels at a time when most PC audio cards had 2 (plus that Yamaha FM synthesizer). There was some hemming and hawing about how the original GUS couldn’t drive all 32 channels at a full 44.1 kHz ("CD quality") playback rate. It’s true— if 14 channels were enabled, all could be played at 44.1 kHz. Enabling more channels started progressive degradation and with all 32 channels, each was only playing at around 19 kHz. Still, from my emerging game programmer perspective, that allowed for 8-channel tracker music and 6 channels of sound effects, all at the vaunted CD level of quality.

  Games and Compatibility
  The primary reason to have a discrete sound card was for entertainment applications — ahem, games. GUS support was pretty sketchy out of the gate (ostensibly a major reason for the card’s delay). While many sound cards offered Sound Blaster emulation by basically having the same hardware as Sound Blaster cards, the GUS took a software route towards emulating the SB. To do this required a program called the Sound Blaster Operating System, or SBOS.

  Oh, how awesome it was to hear the program exclaim "SBOS installed !" And how harshly it grated on your nerves after the 200th time hearing it due to so many reboots and fiddling with options to make your games work. Also, I’ve always wondered if there’s something special about sampling an ’s’ sound — does it strain the sampling frequency range ? Perhaps the phrase was sampled at too low a bitrate because the ’s’ sounds didn’t come through very clearly, which is something you notice after hundreds of iterations when there are 3 ’s’ sounds in the phrase.

  Fortunately, SBOS became less relevant with the advent of Mega-Em, a separate emulator which intercepted calls to Roland MIDI systems and routed them to the very capable GUS. Roland-supporting games sounded beautiful.

  Eventually, more and more DOS games were released with native Gravis support, sometimes with the help of The Miles Sound System (from our friends at Rad Game Tools — you know, the people behind Smacker and Bink). The library changelog is quite the trip down PC memory lane.

  An important area where the GUS shined brightly was that of demos and music trackers. The emerging PC demo scene embraced the powerful GUS (aided, no doubt, by Gravis’ sponsorship of the community) and the coolest computer art and music of the time natively supported the card.

  Programming
  At this point in my life, I was a budding programmer in high school and was fairly intent on programming video games. So far, I had figured out how to make a few blips using a borrowed Sound Blaster card. I went to great lengths to learn how to program the Gravis Ultrasound.

  Oh you kids today, with your easy access to information at the tips of your fingers thanks to Google and the broader internet. I had to track down whatever information I could find through a combination of Prodigy message boards and local dialup BBSes and FidoNet message bases. Gravis was initially tight-lipped about programming information for its powerful card, as was de rigueur of hardware companies (something that largely persists to this day). But Gravis eventually saw an opportunity to one-up encumbent Creative Labs and released a full SDK for the Ultrasound. I wanted the SDK badly.

  So it was early-mid 1993. Gravis released an SDK. I heard that it was available on their support BBS. Their BBS with a long distance phone number. If memory serves, the SDK was only in the neighborhood of 1.5 Mbytes. That takes a long time to transfer via a 2400 baud modem at a time when long distance phone charges were still a thing and not insubstantial.

  Luckily, they also put the SDK on something called an ’FTP site’. Fortunately, about this time, I had the opportunity to get some internet access via the local university.

  Indeed, my entire motivation for initially wanting to get on the internet was to obtain special programming information. Is that nerdy enough for you ?

  I see that the GUS SDK is still available via the Gravis FTP site. The file GUSDK222.ZIP is dated 1998 and is less than a megabyte.

  Next Generation : CD Support
  So I had my original GUS by the end of 1992. That was just the first iteration of the Gravis Ultrasound. The next generation was the GUS MAX. When I was ready to get into the CD-ROM era, this was what I wanted in my computer. This is because the GUS MAX had CD-ROM support. This is odd to think about now when all optical drives have SATA interfaces and (P)ATA interfaces before that— what did CD-ROM compatibility mean back then ? I wasn’t quite sure. But in early 1995, I headed over to Computer City (R.I.P.) and bought a new GUS MAX and Sony double-speed CD-ROM drive to install in the family’s PC.

  
  
  

  About the "CD-ROM compatibility" : It seems that there were numerous competing interfaces in the early days of CD-ROM technology. The GUS MAX simply integrated 3 different CD-ROM controllers onto the audio card. This was superfluous to me since the Sony drive came with an appropriate controller card anyway, though I didn’t figure out that the extra controller card was unnecessary until after I installed it. No matter ; computers of the day were rife with expansion ports.

  
  
  The 3 different CD-ROM controllers on the GUS MAX
  

  Explaining The Difference
  It was difficult to explain the difference in quality to those who didn’t really care. Sometime during 1995, I picked up a quasi-promotional CD-ROM called "The Gravis Ultrasound Experience" from Babbage’s computer store (remember when that was a thing ?). As most PC software had been distributed on floppy discs up until this point, this CD-ROM was an embarrassment of riches. Tons of game demos, scene demos, tracker music, and all the latest GUS drivers and support software.

  Further, the CD-ROM had a number of red book CD audio tracks that illustrated the difference between Sound Blaster cards and the GUS. I remember loaning this to a tech-savvy coworker who disbelieved how awesome the GUS was. The coworker took it home, listened to it, and wholly agreed that the GUS audio sounded better than the SB audio in the comparison — and was thoroughly confused because she was hearing this audio emanating from her Sound Blaster. It was the difference between real-time and pre-rendered audio, I suppose, but I failed to convey that message. I imagine the same issue comes up even today regarding real-time video rendering vs., e.g., a pre-rendered HD cinematic posted on YouTube.

  Regrettably, I can’t find that CD-ROM anymore which leads me to believe that the coworker never gave it back. Too bad, because it was quite the treasure trove.

  Aftermath
  According to folklore I’ve heard, Gravis couldn’t keep up as the world changed to Windows and failed to deliver decent drivers. Indeed, I remember trying to keep my GUS in service under Windows 95 well into 1998 but eventually relented and installed some kind of more appropriate sound card that was better supported under Windows.

  Of course, audio output capability has been standard issue for any PC for at least 10 years and many people aren’t even aware that discrete sound cards still exist. Real-time audio rendering has become less essential as full musical tracks can be composed and compressed into PCM format and delivered with the near limitless space afforded by optical storage.

  A few years ago, it was easy to pick up old GUS cards on eBay for cheap. As of this writing, there are only a few and they’re pricy (but perhaps not selling). Maybe I was just viewing during the trough of no value a few years ago.

  Nowadays, of course, anyone interested in studying the old GUS or getting a nostalgia fix need only boot up the always-excellent DOSBox emulator which provides remarkable GUS emulation support.

• Setting up OpenCV 2.4.6.1 on Ubuntu 12.04.02

  12 août 2013, par Damilola

  I had previously used OpenCV 2.4.5 with some certain configs and packages on Ubuntu 12.04.1 but had issues upgrading to OpenCV 2.4.6.1 on Ubuntu 12.04.2

  I would like to share some ideas (a compilation of noteworthy information gathered from several sources including SO, ubuntu.org, asklinux.org and many other ; and of course by trying several procedures)

  Below is what eventually got me through.

  NOTE : ensure you uninstall any previous installation of OpenCV, FFMpeg and other dependencies previously installed.

  STEP 1 (install ffmpeg and dependencies)

  ---

  # goto http://sourceforge.net/projects/opencvlibrary/files/opencv-unix/
  
  # download the latest stable opencv such as 2.4.6.1 (http://sourceforge.net/projects/opencvlibrary/files/opencv-unix/2.4.5/opencv-2.4.5.1.tar.gz/download) to current directory (such as home or ~/Document)
  
  # cd /opt
  
  # tar -xvf /OpenCV-2.4.6.1.tar.gz
  
  # cd OpenCV-2.4.6.1
  
  # create a foler under current dir (following previous step, this should be ), called prepare
  
  # cd prepare
  
  # Copy the following script to gedit and save as install.sh to current dir, this should be /prepare
  
  # Check corresponding url used in the script for latest versions of the package and replace as required
  
  # Open terminal and navigate to location used above
  
  # sudo chmod +x install.sh
  
  # ./install

  ---

  echo "Removing any pre-installed ffmpeg, x264, and other dependencies (not all the previously installed dependecies)"
  
  sudo apt-get remove ffmpeg x264 libx264-dev libvpx-dev librtmp0 librtmp-dev libopencv-dev
  
  sudo apt-get update
  
  
  
  arch=$(uname -m)
  
  if [ "$arch" == "i686" -o "$arch" == "i386" -o "$arch" == "i486" -o "$arch" == "i586" ]; then
  
  flag=0
  
  else
  
  flag=1
  
  fi
  
  
  
  echo "Installing Dependenices"
  
  sudo apt-get install autoconf automake make g++ curl cmake bzip2 python unzip \
  
    build-essential checkinstall git git-core libass-dev libgpac-dev \
  
    libsdl1.2-dev libtheora-dev libtool libva-dev libvdpau-dev libvorbis-dev libx11-dev \
  
    libxext-dev libxfixes-dev pkg-config texi2html zlib1g-dev
  
  
  
  echo "downloading yasm (assembler used by x264 and FFmpeg)"
  
  # use git or tarball (not both)
  
  wget http://www.tortall.net/projects/yasm/releases/yasm-1.2.0.tar.gz
  
  tar xzvf yasm-1.2.0.tar.gz
  
  cd yasm-1.2.0
  
  
  
  echo "installing yasm"
  
  ./configure
  
  make
  
  sudo make install
  
  cd ..
  
  
  
  echo 'READ NOTE BELOW which was extracted from http://wiki.serviio.org/doku.php?id=build_ffmpeg_linux'
  
  echo 'New version of x264 contains by default support of OpenCL. If not installed or without sense (example Ubuntu 12.04LTS on VMWare) add to configure additional option --disable-opencl. Without this option ffmpeg could not be configured (ERROR: libx264 not found).'
  
  
  
  echo "downloading x264 (H.264 video encoder)"
  
  # use git or tarball (not both)
  
  # git clone http://repo.or.cz/r/x264.git or
  
  git clone git://git.videolan.org/x264.git
  
  cd x264
  
  # wget ftp://ftp.videolan.org/pub/videolan/x264/snapshots/x264-snapshot-20130801-2245-stable.tar.bz2
  
  # tar -xvjf x264-snapshot-20130801-2245-stable.tar.bz2
  
  # cd x264-snapshot-20130801-2245-stable/
  
  
  
  echo "Installing x264"
  
  if [ $flag -eq 0 ]; then
  
  ./configure --enable-static --disable-opencl
  
  else
  
  ./configure --enable-shared --enable-pic --disable-opencl
  
  fi
  
  make
  
  sudo make install
  
  cd ..
  
  
  
  echo "downloading fdk-aac (AAC audio encoder)"
  
  # use git or tarball (not both)
  
  git clone --depth 1 git://github.com/mstorsjo/fdk-aac.git
  
  cd fdk-aac
  
  
  
  echo "installing fdk-aac"
  
  autoreconf -fiv
  
  ./configure --disable-shared
  
  make
  
  sudo make install
  
  cd ..
  
  
  
  echo "installing libmp3lame-dev (MP3 audio encoder.)"
  
  sudo apt-get install libmp3lame-dev
  
  
  
  echo "downloading libopus (Opus audio decoder and encoder.)
  
  wget http://downloads.xiph.org/releases/opus/opus-1.0.3.tar.gz
  
  tar xzvf opus-1.0.3.tar.gz
  
  cd opus-1.0.3
  
  
  
  echo "installing libopus"
  
  ./configure --disable-shared
  
  make
  
  sudo make install
  
  cd ..
  
  
  
  echo "downloading libvpx VP8/VP9 video encoder and decoder)
  
  # use git or tarball (not both)
  
  git clone --depth 1 http://git.chromium.org/webm/libvpx.git
  
  cd libvpx
  
  # wget http://webm.googlecode.com/files/libvpx-v1.1.0.tar.bz2 (this seems not to be update, but can still be used if the fedoraproject link below is not available))
  
  # wget http://pkgs.fedoraproject.org/repo/pkgs/libvpx/libvpx-v1.2.0.tar.bz2/400d7c940c5f9d394893d42ae5f463e6/libvpx-v1.2.0.tar.bz2
  
  # tar xvjf libvpx-v1.2.0.tar.bz2
  
  # cd libvpx-v1.2.0
  
  
  
  echo "installing libvpx"
  
  ./configure --disable-examples
  
  make
  
  sudo make install
  
  cd ..
  
  
  
  sudo ldconfig
  
  
  
  echo "downloading ffmpeg"
  
  # git clone http://repo.or.cz/r/ffmpeg.git
  
  git clone git://source.ffmpeg.org/ffmpeg.git
  
  cd ffmpeg/
  
  # wget http://ffmpeg.org/releases/ffmpeg-2.0.tar.bz2
  
  # tar -xvjf ffmpeg-2.0.tar.bz2
  
  # cd ffmpeg-2.0/
  
  
  
  echo "installing ffmpeg" 
  
  if [ $flag -eq 0 ]; then
  
  ./configure --enable-gpl --enable-libass --enable-libfdk-aac --enable-libopus --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-nonfree --enable-postproc --enable-version3 --enable-x11grab --enable-libvpx
  
  else
  
  ./configure --enable-gpl --enable-libass --enable-libfdk-aac --enable-libopus --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-nonfree --enable-postproc --enable-version3 --enable-x11grab --enable-libvpx --enable-shared
  
  fi
  
  
  
  make
  
  sudo make install
  
  hash -r
  
  
  
  cd .. # move up one level to prepare folder
  
  cd .. # move up one level to opencv folder
  
  
  
  echo "Checking to see if you're using your new ffmpeg"
  
  ffmpeg 2>&1 | head -n1
  
  
  
  sudo ldconfig

  STEP 2 (Install OpenCV and necessary packages)

  echo "Installing Dependenices"
  
  sudo apt-get install libopencv-dev
  
  sudo apt-get install libtiff4-dev libjpeg-dev libjasper-dev
  
  
  
  echo "installing Video I/O libraries, support for Firewire video cameras and video streaming libraries"
  
  sudo apt-get install libav-tools libavcodec-dev libavformat-dev libswscale-dev libdc1394-22-dev libxine-dev libgstreamer0.10-dev libgstreamer-plugins-base0.10-dev libv4l-dev v4l-utils v4l-conf
  
  
  
  echo "installing the Python development environment and the Python Numerical library"
  
  sudo apt-get install python-dev python-numpy
  
  
  
  echo "installing the parallel code processing library (the Intel tbb library)"
  
  sudo apt-get install libtbb-dev
  
  
  
  echo "installing the Qt dev library"
  
  sudo apt-get install libqt4-dev libgtk2.0-dev
  
  
  
  echo "installing other dependencies (if need be it would upgrade current version of the packages)"
  
  sudo apt-get install patch subversion ruby librtmp0 librtmp-dev libfaac-dev libmp3lame-dev libopencore-amrnb-dev libopencore-amrwb-dev libvpx-dev libxvidcore-dev
  
  
  
  echo installing optional packages"
  
  sudo apt-get install libdc1394-utils libdc1394-22-dev libdc1394-22 libjpeg-dev libpng-dev libtiff-dev libjasper-dev

  STEP 3 (run ldconfig)

  # Open a new terminal window
  
  # Open /etc/ld.so.conf and check, 
  
  # if the paths "/usr/lib" and "/usr/local/lib" including the quote exist in the file. If not, add them manually or by
  
      sudo echo "/usr/local/lib" >> /etc/ld.so.conf
  
      sudo echo "/usr/lib" >> /etc/ld.so.conf
  
  # execute the following
  
      sudo ldconfig

  STEP 4

  # still ensure you haven't close the new terminal window open in STEP 3
  
  # execute the following
  
      mkdir build
  
      cd build
  
      cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D BUILD_SHARED_LIBS=OFF -D WITH_TBB=ON -D BUILD_NEW_PYTHON_SUPPORT=ON -D WITH_V4L=ON -D INSTALL_C_EXAMPLES=ON -D INSTALL_PYTHON_EXAMPLES=ON -D BUILD_EXAMPLES=ON -D WITH_QT=ON -D WITH_OPENGL=ON ..
  
  
  
      make
  
      sudo make install
  
  
  
  # add the following to user environment variable ~/.bashrc
  
      export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:/usr/local/lib
  
      export PKG_CONFIG_PATH=${PKG_CONFIG_PATH}:/usr/local/lib/pkgconfig
  
  # execute the following
  
      sudo ldconfig
  
  # start to use and enjoy opencv, it should have been install into these locations
  
  #   /usr/local/include/, /usr/local/share/, /usr/local/lib/

  STEP 5 (install v4l : Note : installing v4l-utils after opencv installation works for Ubuntu 12.04.2 & OpenCV 2.4.6.1)

  # still ensure you haven't close the new terminal window open in STEP 3
  
  # goto http://www.linuxtv.org/downloads/v4l-utils
  
  # download the latest v4l such as v4l-utils-0.9.5.tar.bz2
  
  # copy the downloaded file to the current terminal dir (following previous step, this should be /prepare)
  
  # execute the following
  
      tar -xvjf v4l-utils-0.9.5.tar.bz2
  
      cd v4l-utils-0.9.5/
  
      ./configure
  
      make
  
      sudo make install
  
      cd ..
  
      cd .. # (to go to )
  
      sudo ldconfig

  Worth Noting

  # To check the path where opencv & other lib files are stored, do:
  
  
  
  
  
  pkg-config --cflags opencv
  
  
  
      (output will come as)
  
      -I/usr/include/opencv
  
  
  
  
  
  
  
  pkg-config --libs opencv
  
  
  
      (output will come as)
  
      -lopencv_core -lopencv_imgproc -lopencv_highgui -lopencv_ --ml -lopencv_video -lopencv_features2d -lopencv_calib3d -lopencv_objdetect -lopencv_contrib -lopencv_legacy -lopencv_flann
  
  
  
  # The above paths are needed to compile your opencv programs, as given in the next illustration.
  
  
  
  # write a simple C program to test, by saving below program in a file named DisplayImage.c
  
  
  
  #include 
  
      #include <opencv2></opencv2>highgui/highgui.hpp>
  
  
  
      int main(int argc, char *argv[]) {
  
          IplImage* img=0; /* pointer to an image */
  
          printf("Hello\n");
  
  
  
          if(argv[1] != 0)
  
              img = cvLoadImage(argv[1], 0); // 1 for color
  
          else
  
              printf("Enter filename\n");
  
  
  
          if(img != 0) {
  
              cvNamedWindow("Display", CV_WINDOW_AUTOSIZE); // create a window
  
              cvShowImage("Display", img); // show image in window
  
              cvWaitKey(0); // wait until user hits a key
  
              cvDestroyWindow("Display");
  
          }
  
          else
  
              printf("File not found\n");
  
  
  
          return 0;
  
      }
  
  
  
  # write a simple C++ program to test, by saving below program in a file named DisplayImage.cpp
  
  
  
  #include 
  
  #include <opencv2></opencv2>opencv.hpp>
  
  #include <opencv2></opencv2>highgui/highgui.hpp>
  
  
  
  using namespace cv;
  
  
  
  int main( int argc, char** argv )
  
  {
  
    Mat image;
  
    image = imread( argv[1], 1 );
  
  
  
    if( argc != 2 || !image.data )
  
      {
  
        printf( "No image data \n" );
  
        return -1;
  
      }
  
  
  
    namedWindow( "Display Image", CV_WINDOW_AUTOSIZE );
  
    imshow( "Display Image", image );
  
  
  
    waitKey(0);
  
  
  
    return 0;
  
  }
  
  
  
  # To compile &amp; run :
  
  
  
  
  
  
  
  g++  `pkg-config --cflags --libs opencv` &amp;&amp; ./a.out img
  
  
  
  or
  
  
  
  
  
  
  
  g++ -I/usr/include/opencv -I/usr/local/include -lopencv_core -lopencv_highgui -lopencv_ml -lopencv_imgproc -lopencv_video -lopencv_features2d -lopencv_calib3d -lopencv_objdetect -lopencv_contrib -lopencv_legacy -lopencv_flann -lopencv_nonfree  &amp;&amp; ./a.out img
  
  
  
  where “img” is the name of any image with extension within the same folder .
  
  You should be able to see “Hello” and the image in a different window.
  
  
  
  If this runs, Congrats! now you can run any C/C++ program with opencv lib.
  
  
  
  
  
  # Now lets simplify the above big command by making a shortcut for it:
  
  go to your local home directory(cd /home/) and open the .bashrc file using gedit(the file will be hidden). Append the following to the file:
  
  
  
  
  
  
  
  alias gcv="g++ -I/usr/include/opencv -I/usr/local/include -lopencv_core -lopencv_highgui -lopencv_ml -lopencv_imgproc -lopencv_video -lopencv_features2d -lopencv_calib3d -lopencv_objdetect -lopencv_contrib -lopencv_legacy -lopencv_flann -lopencv_nonfree"
  
  
  
  and save. Close the terminal and open it again.(as this process requires relogin of the terminal)
  
  
  
  # Now, go to directory containing a sample program &amp; do
  
  
  
  
  
  
  
  gcv  &amp;&amp; ./a.out
  
  
  
  or
  
  
  
  
  
  
  
  gcv 
  
      ./a.out input_img.jpg

  As you can see the commands now become similar to $cc filename.c, $./a.out which are used normally for compiling and executing C/C++ programs.

  ---

  Some ways to check whether all lib files are installed-

  apt-cache search opencv

  returns :

  libcv-dev - Translation package for libcv-dev
  
  libcv2.3 - computer vision library - libcv* translation package
  
  libcvaux-dev - Translation package for libcvaux-dev
  
  libcvaux2.3 - computer vision library - libcvaux translation package
  
  libhighgui-dev - Translation package for libhighgui-dev
  
  libhighgui2.3 - computer vision library - libhighgui translation package
  
  libopencv-calib3d-dev - development files for libopencv-calib3d
  
  libopencv-calib3d2.3 - computer vision Camera Calibration library
  
  libopencv-contrib-dev - development files for libopencv-contrib
  
  libopencv-contrib2.3 - computer vision contrib library
  
  libopencv-core-dev - development files for libopencv-core
  
  libopencv-core2.3 - computer vision core library
  
  libopencv-dev - development files for opencv
  
  libopencv-features2d-dev - development files for libopencv-features2d
  
  libopencv-features2d2.3 - computer vision Feature Detection and Descriptor Extraction library
  
  libopencv-flann-dev - development files for libopencv-flann
  
  libopencv-flann2.3 - computer vision Clustering and Search in Multi-Dimensional spaces library
  
  libopencv-gpu-dev - development files for libopencv-gpu
  
  libopencv-gpu2.3 - computer vision GPU Processing library
  
  libopencv-highgui-dev - development files for libopencv-highgui
  
  libopencv-highgui2.3 - computer vision High-level GUI and Media I/O library
  
  libopencv-imgproc-dev - development files for libopencv-imgproc
  
  libopencv-imgproc2.3 - computer vision Image Processing library
  
  libopencv-legacy-dev - development files for libopencv-legacy
  
  libopencv-legacy2.3 - computer vision legacy library
  
  libopencv-ml-dev - development files for libopencv-ml
  
  libopencv-ml2.3 - computer vision Machine Learning library
  
  libopencv-objdetect-dev - development files for libopencv-objdetect
  
  libopencv-objdetect2.3 - computer vision Object Detection library
  
  libopencv-video-dev - development files for libopencv-video
  
  libopencv-video2.3 - computer vision Video analysis library
  
  opencv-doc - OpenCV documentation and examples
  
  python-opencv - Python bindings for the computer vision library