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• blank transparent pngs behave like black canvas

  10 novembre 2015, par Anay Bose

  I am trying to create a scrolling image with imagemagick’s roll and crop functions. Its a frame-by—frame animation. The source image is a transparent png with some text written on it. The following code works and it creates the required frames, including some blank png images at first for a nice, smooth effect. These blank pngs are what creating problems when I am trying to convert my image frames into video with ffmpeg. FFMPEG is seemingly considering these blank pngs as black/dark images, so the resulting video contains a blackout for a few seconds in the beginning—which I do not want.

  I am using png codec with bgra pixel format. My ffmpeg command (shown below) creates smooth, clear animation with images that have some text on it.

  "ffmpeg -i trans/trans-%d.png -vcodec png -pix_fmt bgra overlay-0.mov";

  The blank pngs behave like black canvas, but as I try to write some text on them or surround them with a border (i.e. colorize in some way) the problem disappears—which seems very strange. I have tested all my images ; they are all transparent. For the past few hours, I have been searching for a solution, no luck so far. Please note those blank pngs are required in the beginning for a smooth effect, and I cannot omit them. I have uploaded a sample video in Youtube. Please note the black fade out.

  https://www.youtube.com/watch?v=Te3LuItxcDk&feature=youtu.be

  https://youtu.be/Te3LuItxcDk

  PHP code :

     $increment = 40;
  
     $count = 0; 
  
  
  
     for ($x=40; $x <= 640 ; $x+=$increment) 
  
     {
  
       $roll = new Imagick(DOCROOT . '/composite-0.png');
  
       $roll->rollImage($x, 0);
  
       $roll->writeImage(DOCROOT . '/roll/roll-' . $x . '.png');
  
  
  
      $crop = new Imagick(DOCROOT . '/roll/roll-' . $x . '.png');
  
      $crop->cropImage($x, 720, 0, 0);
  
      $crop->writeImage(DOCROOT . '/roll/crop-' . $x . '.png');
  
  
  
      $extent = new Imagick(DOCROOT . '/roll/crop-' . $x . '.png'); 
  
      # $extent->setImageBackgroundColor(new ImagickPixel('none'));
  
      $extent->setImageBackgroundColor(new ImagickPixel('transparent'));
  
      $extent->extentImage(640, $extent->getImageHeight(), 0, 0);
  
      $extent->setImageFormat('png'); 
  
      $extent->writeImage(DOCROOT . '/trans/trans-' . $count . '.png');
  
  
  
      $count++; 
  
     }

• Catalyst Open Source Academy

  16 janvier 2015, par Matthieu Aubry — Community

  The Open Source Academy is an initiative designed to provide training and work experience for young New Zealand technologists. Catalyst organises the Academy to show young technologists how to participate in open source communities and to fully explore their passion for IT through freely available open source tools.

  It has been running annually since 2011. We are proud that Piwik project could participate in the Academy again this year !

  What students got done

  It’s amazing what a few young students can get done in four days of participating in an open source project like Piwik ! They were able to quickly get started with Piwik, and continued to make useful contributions to the Piwik analytics platform.

  New Darkness theme

  Liam has created a new dark theme for Piwik called Darkness.

  

  To create the theme, Liam had to improve Piwik core stylesheets and created this pull request : Reuse the LESS variable for white color across all stylesheets.

  Accessibility improvements

  We were lucky to spend time with Julius, a Catalyst employee who is blind. He showed us in great detail how difficult and time consuming it can be for a blind user to use Piwik. For example we noticed how complicated it was for Julius to navigate the menus, to get to the main content, and to use the calendar and the Website selector. During this presentation we also noticed that Piwik was not yet usable with the keyboard.

  As a result of this session with Julius we got to work with the students to improve accessibility in Piwik.

  

  (photo source)

  List of accessibility improvements

  All these pull requests were created by the students and have been successfully merged into Piwik :

  • see the focus of menu items when tabbing through the page
  • Tweaks to improve accessibility (section around graph, better tooltip, set language in html)
  • Added h3 tags to widget headers
  • when main Menu is focused, display submenu
  • Add “Skip to content” feature when user presses tab key
  • Improved accessibility by putting offscreen text in the widget title

  To learn more about accessibility in Piwik check out this issue on our tracker.

  Summary

  Working with young students was fun and interesting. We were excited to see how much they got done in such a short time !

  At Piwik and Piwik PRO we are committed to building the best open analytics platform, and we will continue to support students who want to take part in the Piwik adventure.

  Be well,

• ffmpeg streaming camera with directshow

  17 novembre 2015, par atu0830

  I am trying use ffmpeg to streaming one camera. The command is

  ffmpeg.exe -y  -f dshow -i video="AmCam" -c:v copy  -framerate 7.5 -map 0:0 -f ssegment -segment_time 4 -segment_format mpegts  -segment_list "web\stream.m3u8"  -segment_list_size 720  -segment_list_flags live  -segment_wrap 10 -segment_list_type m3u8  "web\segments\s%%d.ts"

  And I create a html in web folder

                                        
  
                                  
  
                                       
  
                                    
  
      <video controls="controls" width="720" height="405" autoplay="autoplay">   
  
          <source src="stream.m3u8" type="application/x-mpegURL"></source>           
  
      </video>                                    
  
                                       
  
   

  All ts file generated but looking Safari on iPad looding but it always show dark player and loading