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• How to generate light weight videos with ffmpeg for Power Point in OS X ?

  25 septembre 2014, par Pablo

  I want to make some movies with ffmpeg to use them on a Powerpoint in Mac OS X. I am using this command, which works well but generates large movies (about 100 MB) without losing too much quality.

  ffmpeg -f image2 -r 100 -pattern_type glob -i 'img*.png' -c:v mjpeg -qscale:v 20 test.avi

  I have also tried using other codecs like mpeg4 and libx264 to generate lighter movies (about 10 MB) but they don’t work correctly in the Powerpoint presentation.

  Does anyone know how to use them correctly or how to create a light weight movie with ffmpeg that works well on Powerpoint for OS X ?

• The transparent pixels in my Bitmap shown as white

  7 mai 2016, par Hassan Ibrahem

  I’m using c code to get frame from a gif file and it’s working fine using ffmpeg library av_read_frame, then I convert the returned image from this format BGRA to ARGB format using this method libyuv::ABGRToARGB.

  In the java part I receive the bitmap and when I put it in the ImageView the transparent pixels drawn white.

   Bitmap bitmap= Bitmap.createBitmap(150, 150, Bitmap.Config.ARGB_8888);
  
   getGifFrame(gifFile,bitmap); //native method which get image frame from gif file.
  
   imageTest.setImageBitmap(backgroundBitmap);//this bitmap in debug mode I can see that it has transparent pixels, but in drawn it appears white!

  even when I loop on the returned bitmap pixels and check for each pixel I find them transparent !

            for (int x = 0; x < b.getWidth(); x++)
  
              {
  
                  for (int y = 0; y < b.getHeight(); y++)
  
                  {
  
                      int color = b.getPixel(x, y);
  
                      if (color == Color.WHITE)//This condition never occurred 
  
                      {
  
                          b.setPixel(x, y, Color.TRANSPARENT);
  
                      }
  
                  }
  
              }

  Nothing happened and it’s still white. Then I did convert all transparent pixels to TRANSPARENT !! and guess what, It’s working !

  else if (color == Color.TRANSPARENT)
  
  {
  
    b.setPixel(x, y, Color.TRANSPARENT);
  
  }

  I don’t understand why that happen. Any help would be appreciated.

  EDIT 1 :
  I get all pixels from the bitmap and set them again without doing anything and it worked also !?

    bitmap.getPixels(pixels, 0, width, 0, 0, width, height);
  
    bitmap.setPixels(pixels, 0, width, 0, 0, width,height);

• OBS alternative for server : Creating a continuous video streaming to RTMP server and beign able to manipulate it using NodeJS

  27 juillet 2016, par futufu

  What I want is to be able to create a livestream from a Ubuntu v14.04 server to a RTMP Server (like Twitch) and to be able to use NodeJS to control visual aspects (adding layers, text, images) and add different sources (video files, others livestreams, etc). Like having OBS running on a server.

  What I’ve done/researched so far :

  FFmpeg

  With ffmpeg I can can create video files streams like that :

  ffmpeg -re -i video.mp4 -c:v libx264 -preset fast -c:a aac -ab 128k -ar 44100 -f flv rtmp://example.com

  Also using the filter_complex I can create something near to a layer like this tutorial explains :
  https://trac.ffmpeg.org/wiki/Create%20a%20mosaic%20out%20of%20several%20input%20videos

  But I found the following problems :

  • The streams that I create with ffmpeg only last until the video file is over, if I wanted to stream multiple video files (dynamic playlist) it would interrupt the stream between each file ;
  • The manipulation is very limited as far as I am concerned, I can’t edit filter_complex once ffmpeg is executing ;
  • Can’t display text and create animated overlays, like sliding text.

  I tried to search for any cli/nodejs package that is able to create a continuos video stream and manipulate it to use as input source for ffmpeg which streams to the RTMP server.

  Can someone give me more information about what I am trying to do ?

  I’m playing with github.com/fluent-ffmpeg/node-fluent-ffmpeg to see if I have a different outcome.