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• Cannot get ffmpeg2.3.3 to work with Opencv2.4.9

  6 septembre 2014, par Siddharthan P R

  I need to open a video file in opencv2.4.9. I used the following code and I got the output :
   !!! Sorry cant find the video file !!!.

  So I figured I need to install ffmpeg first then install opencv.
  So I Uninstalled opencv and ffmpeg then tried to install ffmpeg 2.3.3 properly.
  Here are the methods i tried to install ffmpeg.

  Method 1 :
  sudo apt-get install ffmpeg.

  Method 2 :
  Download (HTTP) : http://ffmpeg.org/releases/ffmpeg-2.3.3.tar.bz2

  Then i typed the following in the terminal after cd to the extracted folder.

  sed -i 's/-lflite"/-lflite -lasound"/' configure && 
  
  
  
  ./configure --prefix=/usr        \
  
              --enable-gpl         \
  
              --enable-version3    \
  
              --enable-nonfree     \
  
              --disable-static     \
  
              --enable-shared      \
  
              --disable-debug      \
  
              --enable-libass      \
  
              --enable-libfdk-aac  \
  
              --enable-libmp3lame  \
  
              --enable-libtheora   \
  
              --enable-libvorbis   \
  
              --enable-libvpx      \
  
              --enable-libx264     \
  
              --enable-x11grab     &&
  
  make &&
  
  gcc tools/qt-faststart.c -o tools/qt-faststart

  Though Method 1 works fine (in just installing ffmpeg), the problem with Method 1 is that i cannot use "./configure —enable-shared" anywhere because i cannot locate the file "configure".

  The problem with method 2 is that it says

  -ERROR: libass not found, after installing libass it says
  
  
  
  -ERROR: libfdk-aac-0.1.3 not found, then
  
  
  
  -ERROR: lame-3.8 not found, then
  
  
  
  -ERROR: libtheora not found, here i really got tired of installing all these packages. I stopped.

  I am really confused how to pull this off : with Method 1 or Method 2 (both seem not to work ). Can i change the ./ configure using method 1 ?

  Any help would be greatly appreciated.

              #include 
  
              #include 
  
  
  
              int main(int argc, char** argv) 
  
              {
  
                  cvNamedWindow("xample2", CV_WINDOW_AUTOSIZE);
  
                  CvCapture* capture = cvCreateFileCapture( "1.mp4" );
  
                  if (!capture)
  
                  {
  
                    std::cout << "!!! Sorry cant find the video file !!!\n";
  
                    return -1; 
  
                  }
  
  
  
                  IplImage* frame;
  
                  while (1) 
  
                  {
  
                      frame = cvQueryFrame(capture);
  
                      if(!frame) 
  
                          break;
  
  
  
                      cvShowImage("xample2", frame);
  
  
  
                      char c = cvWaitKey(33);
  
                      if (c == 27) 
  
                          break;
  
                  }
  
  
  
                  cvReleaseCapture(&capture);
  
                  cvDestroyWindow("xample2");
  
              }

• ffmpeg itsoffset doesn't work with pcm audio and raw 264 video

  28 janvier 2019, par Danny

  I need to create an MP4 container with data from a hardware encoder. The encoder outputs PCM 16-bit signed audio and raw H.264 ES video frames.

  This ffmpeg command line I’ve got works but the audio and video are not sync’d.

  From other posts I know that itsoffset only works with video and probably doesn’t work with -v copy

  I’ve confirmed that applying an itsoffset has no effect.

  Here’s the command line. Any suggestions ?

  One post suggested itsoffset works if you re-encode the video. But doing that needs CPU power and adds latency. (And what’s the point of a hardware encoder then ?)

  ffmpeg -f s16le -ar 44.1k -ac 2      -i Audio_20190110-165736.pcm 
  
         -fflags +genpts -itsoffset -5 -i Video_20190110-165736.264
  
         -c:v copy -c:a aac -b:a 128k 
  
         -f mp4 -movflags +faststart  output.mp4

  EDIT I

  Here is a link to the audio/video input files referenced in the above command.

• Why menconder fps rate does not work ?

  2 mars 2016, par ACR

  I’m using mencoder to create a video out of some .png files. The problem is that the frame rate doesn’t change, regardless of the -fps flag. The output video has different time lengths (in their properties), but the video’s size and speed are always the same (regardless of the FPS chosen).

  I just want to create a shorted video by using higher FPS rates. In short, a "time-lapse" of my original set of images. What am I doing wrong with mencoder ? I’m using the following command :

  mencoder mf://./IMG/images*.png -mf w=800:h=600:fps=20:type=png -ovc copy -oac copy -o video.avi