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• Music Video Idiosyncrasies

  18 juin 2011, par Multimedia Mike — General

  So I’m watching a fairly recent music video for a song named "XXXO" from an artist named M.I.A. when I’m suddenly assaulted by this imagery :

  
  
  

  ... and I enter nervous convulsions. You see, while this might seem to be an odd video effect to the casual viewer, to a multimedia hacker, it appears to be deliberately antagonistic. To anyone who has written a video codec, this scene looks like an entire casserole of video bugs, combining creeping plane offsets errors, chroma problems, and interlacing havoc. The craziest part is to realize that this is probably some kind of standard video effect / filter type. Upon a repeat viewing, I realized that the entire video sort of looks like an amateur video editor’s first week using video software.

  Elsewhere in the video, a YouTube-style video frame vortex highlights the proceedings. I guess I need to come to terms with the fact that the ubiquitous player frame is just part of the digital Zeitgeist now :

  
  
  

  Vintage Video Strangeness
  I’m a long-time music video junkie but I have a tendency of examining them entirely too closely. I first saw Paula Abdul’s video for "Cold-Hearted" when I was just starting to understand multimedia technology and how it interacted with emerging home computers. Imagine how confused I was when I tried to make sense of the actions performed by our eMaestro "Chuck" whom Paula has instructed to "hit it". First, he hits a key followed by 3 quick strikes on a second key :

  
  
  

  Then, the "start music" action is apparently bound to a particular key on the electronic keyboard :
  
  

  
  
  

  Which kicks off the electronic metronome on the computer. Each identical-sounding beat quizzically maps to a different frequency transform :

  
  
  a one...
  
  and a two...
  
  and a three...
  

  I had no trouble believing things up to this point. But even though I didn’t understand what was going on with that frequency transform, I knew that it must have had something to do with the audio. And if the audio was the same, the visualization ought to be the same. Though, to be fair, I will concede that the first and third ticks pictured bear some mutual resemblance.

  Anyway, the software is probably real even if the keyboard interaction was stylized. Can anyone identify the software ? What about the computer ? This is perhaps the best view the video gives us :

  
  
  

  So, remember, don’t base your understanding of technology — or anything, really — on stylized media representations. Don’t even get me started on the movie "Sneakers." That had me confused about cryptography and computer security for many years.

• OpenCV 2.4.7 with FFMpeg support build with VS 2010 (x86)

  24 novembre 2013, par GregPhil

  I'm fighting with new version of OpenCV 2.4.7 for almost one week (prev. used 2.4.2). My motivation for the new setup is the fact that I run into problems using the Videowriter for uncompressed grayscale videos (http://answers.opencv.org/question/3603/videowriter-videocapture-and-uncompressed-avi/). In https://github.com/Itseez/opencv/pull/1516 "akarsakov" is recommending to build OpenCV without vfw support and open uncompressed video through ffmpeg. That's what I tried to do. I followed basically the instructions mentioned in this video : http://docs.opencv.org/trunk/doc/tutorials/introduction/windows_install/windows_install.html

  I had successfully build opencv with Qt 5.1.1 (http://answers.opencv.org/question/24184/how-to-compile-opencv-247-with-qt-and-ffmpeg/). But I'm not able to get the VideoWriter & VideoCapture work for me. So what I did :

  1. I downloaded the newest ffmpeg build from http://ffmpeg.zeranoe.com/builds/

  2. I generated the vs2010 project disabling VfW and enabling ffmpeg instead :

     Video I/O:
     
     
     
     Video for Windows:           NO
     
     DC1394 1.x:                  NO
     
     DC1394 2.x:                  NO
     
     FFMPEG:                      YES (prebuilt binaries)
     
       codec:                     YES (ver 55.18.102)
     
       format:                    YES (ver 55.12.100)
     
       util:                      YES (ver 52.38.100)
     
       swscale:                   YES (ver 2.3.100)
     
       gentoo-style:              YES
     
       OpenNI:                    NO
     
     OpenNI PrimeSensor Modules:  NO
     
     PvAPI:                       NO
     
     GigEVisionSDK:               NO
     
     DirectShow:                  YES
     
     Media Foundation:            NO
     
     XIMEA:                       NO

  3. I added the include directories and libs for ffmpeg to the highgui module.

  I was not able to compile OpenCV without any errors but the behaviour what I see is not what I expect :

  1. Build OpenCV 2.4.7 without VfW -> VideoWriter.open () returns always false !
  2. Build OpenCV 2.4.7 with VfW -> VideoWriter.open () returns true for the time, calling a release() and an open() on the same object returns always a false.
  3. With or without ffmpeg -> An VideoCapture.open () gives a error message asking for libiconv-2dll !

  Does some had the same problems and is able to point me to my mistake ?

  Thank you in advance.
  cheers

• ffmpeg throwing "errorMessage" : "spawn ffmpeg ENOENT"

  25 avril 2016, par user2792129

  My ffmpeg function thats running as a shell command isnt working. I think its because ’ffmpeg’ isnt really referring to anything. I have the ffmpeg node module in my bundle, but i dont know the execFile command is referring to it here.

  Im following aws-lambda-ffmpeg as an example of how to call this particular function. They are referring to ’ffmpeg’ as a 64-bit linux build they created from John Vansickle’s static FFMPEG builds in their gulp function.

  I want to know how to replace ’ffmpeg’ with something that will just recognize it like a node_module without having to do the whole gulp static build process. To my understanding the only reason they are doing that is to get the latest build which i really dont need.

  If I am wrong and a static build using gulp is needed for another reason please let me know.

  function ffmpegProcess(description, cb) {
  
  console.log('Starting FFmpeg');
  
  
  
  child_process.execFile(
  
      'ffmpeg',
  
      [
  
          '-y',
  
          '-loglevel', 'warning',
  
          '-i', 'download',
  
          '-c:a', 'copy',
  
          '-vf', scaleFilter,
  
          '-movflags', '+faststart',
  
          '-metadata', 'description=' + description,
  
          'out.' + config.format.video.extension,
  
          '-vf', 'thumbnail',
  
          '-vf', scaleFilter,
  
          '-vframes', '1',
  
          'out.' + config.format.image.extension
  
      ],
  
      {
  
          cwd: tempDir
  
      },
  
      function(err, stdout, stderr) {
  
          console.log('FFmpeg done.');
  
          return cb(err, 'FFmpeg finished:' + JSON.stringify({ stdout: stdout, stderr: stderr}));
  
      }
  
  );
  
  }