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• Padding thumbnail with color

  9 juin 2010, par Mikko Koppanen — Imagick, PHP stuff

  I know, it’s been a while since I last blogged. This is because a lot of things are happening in my personal life. I recently relocated to London from Finland and started a new job. Things are quite busy but I will try to post an example now and then. In the meanwhile I would like to hear about sites using Imagick, so if your project is not super secret please post an url and maybe a small explanation what you’re doing with Imagick on the site. This is purely for my personal interest.

  Anyway, to the point. Today’s example originates from a question asked by a user. How do I thumbnail the image inside given dimensions proportionally and fill the “blank” areas with a color ? Well, the answer is here

  The code is for Imagick 2.1.0 but adapting to older versions should not be hard.

  php

  < view plain text >

  1. < ?php
  2. /* Define width and height of the thumbnail */
  3. $width = 100 ;
  4. $height = 100 ;
  5.  
  6. /* Instanciate and read the image in */
  7. $im = new Imagick( "test.png" ) ;
  8.  
  9. /* Fit the image into $width x $height box
  10.  The third parameter fits the image into a "bounding box" */
  11. $im->thumbnailImage( $width, $height, true ) ;
  12.  
  13. /* Create a canvas with the desired color */
  14. $canvas = new Imagick() ;
  15. $canvas->newImage( $width, $height, ’pink’, ’png’ ) ;
  16.  
  17. /* Get the image geometry */
  18. $geometry = $im->getImageGeometry() ;
  19.  
  20. /* The overlay x and y coordinates */
  21. $x = ( $width - $geometry[’width’] ) / 2 ;
  22. $y = ( $height - $geometry[’height’] ) / 2 ;
  23.  
  24. /* Composite on the canvas */
  25. $canvas->compositeImage( $im, imagick: :COMPOSITE_OVER, $x, $y ) ;
  26.  
  27. /* Output the image*/
  28. header( "Content-Type : image/png" ) ;
  29. echo $canvas ;
  30.  
  31.  ?>

  The source image :
  

  The resulting image :
  

• Typesetting

  9 juin 2010, par Mikko Koppanen — Imagick, PHP stuff

  Ever had the situation where you have a piece of string which you need to overlay on an image ? Maybe a situation where the area reserved for the string is known in pixels but you need to know the font size to fill most of the area ? Think no more !

  Here is a small example of how to fit a certain piece of a string on to an area of which you know the width and the height or only the width. The magic happens through the ImageMagick CAPTION : format. You can see from the example images how the parameters actually affect the image.

  php

  < view plain text >

  1. < ?php
  2.  
  3. /* How wide is our image */
  4. $image_width = 200 ;
  5.  
  6. /* Give zero for autocalculating the height */
  7. $image_height = 200 ;
  8.  
  9. /* Specify the text */
  10. $text = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
  11.     Mauris lectus mi, mattis non, euismod vel, sagittis nec, ipsum." ;
  12.  
  13. /* Instanciate imagick */
  14. $im = new Imagick() ;
  15.  
  16. /* Create new image using caption : pseudo format */
  17. $im->newPseudoImage( $image_width, $image_height, "caption :" . $text ) ;
  18.  
  19. /* Put 1px border around the image */
  20. $im->borderImage( ’black’, 1, 1 ) ;
  21.  
  22. /* PNG format */
  23. $im->setImageFormat( "png")  ;
  24.  
  25. /* Output */
  26. header( "Content-Type : image/png" ) ;
  27. echo $im ;
  28.  
  29.  ?>

  Here is image with width 100 and height 0 :

  

  Width 100 Height 50 :

  

  Width 200 Height 200 (as you can see the font size is now larger) :

  

• APPLY Strong to Buffer rule. Quit Switching Bit rates MPEG DASH

  14 juillet 2015, par Vinay

  I am using mpeg dash for adaptive bit rate streaming of video from my server.

  I have used ffmpeg and MP4Box to generate 4 different quality video files from my source .mp4

  The .mpd file generated has the below code

  <?xml version="1.0"?>
  
  
  
  <mpd xmlns="urn:mpeg:dash:schema:mpd:2011" minbuffertime="PT1.500000S" type="static" mediapresentationduration="PT0H3M1.42S" profiles="urn:mpeg:dash:profile:isoff-on-demand:2011">
  
   <programinformation moreinformationurl="http://gpac.sourceforge.net">
  
    
  
   </programinformation>
  
  
  
   <period duration="PT0H3M1.42S">
  
    <adaptationset segmentalignment="true" maxwidth="1920" maxheight="1080" maxframerate="24" par="16:9" lang="und" subsegmentstartswithsap="1">
  
     <representation mimetype="video/mp4" codecs="avc1.64000d" width="320" height="240" framerate="24" sar="1:1" startwithsap="1" bandwidth="375715">
  
      <baseurl>400_dashinit.mp4</baseurl>
  
      <segmentbase indexrangeexact="true" indexrange="904-1403">
  
        <initialization range="0-903"></initialization>
  
      </segmentbase>
  
     </representation>
  
     <representation mimetype="video/mp4" codecs="avc1.640015" width="420" height="270" framerate="24" sar="1:1" startwithsap="1" bandwidth="644824">
  
      <baseurl>700_dashinit.mp4</baseurl>
  
      <segmentbase indexrangeexact="true" indexrange="905-1404">
  
        <initialization range="0-904"></initialization>
  
      </segmentbase>
  
     </representation>
  
     <representation mimetype="video/mp4" codecs="avc1.64001f" width="1024" height="576" framerate="24" sar="1:1" startwithsap="1" bandwidth="1349484">
  
      <baseurl>1500_dashinit.mp4</baseurl>
  
      <segmentbase indexrangeexact="true" indexrange="905-1404">
  
        <initialization range="0-904"></initialization>
  
      </segmentbase>
  
     </representation>
  
     <representation mimetype="video/mp4" codecs="avc1.64001f" width="1280" height="720" framerate="24" sar="1:1" startwithsap="1" bandwidth="2264379">
  
      <baseurl>2500_dashinit.mp4</baseurl>
  
      <segmentbase indexrangeexact="true" indexrange="905-1404">
  
        <initialization range="0-904"></initialization>
  
      </segmentbase>
  
     </representation>
  
     <representation mimetype="video/mp4" codecs="avc1.640028" width="1920" height="1080" framerate="24" sar="1:1" startwithsap="1" bandwidth="3633049">
  
      <baseurl>4000_dashinit.mp4</baseurl>
  
      <segmentbase indexrangeexact="true" indexrange="906-1405">
  
        <initialization range="0-905"></initialization>
  
      </segmentbase>
  
     </representation>
  
    </adaptationset>
  
   </period>
  
  </mpd>

  I am using video.js along with dash.js to playback the mpeg dash content on client side. The issue is that the video doesn’t playback perfectly when i simulate network conditions from chrome dev tools.

  It works at times and it doesn’t at others. For ex the stream starts with bit rate of 400kbps and then detects enough bandwidth available so it switches to 2500kbps. Then when i bring down my bandwidth to 400kbps again then the video freezes at some point of time.

  At times the video freezes after few initial seconds of playback when it tries to switch the stream. I think there might be some command line parameter that i am missing while generating my video files via ffmpeg or generating .mpd file via MP4Box.

  below are the commands i use for ffmpeg and MP4Box

  ffmpeg -y -i inputfile -c:a libfdk_aac -ac 2 -ab 128k -c:v libx264 -r 24 – g 24 -b:v 1500k -maxrate 1500k -bufsize 1000k -vf "scale=-1:720" outputfile.mp4
  
  
  
  
  
  MP4Box -dash [DURATION] -rap -frag-rap -profile [PROFILE] -out [path/to/outpout.file] [path/to/input1.file] [path/to/input2.file] [path/to/input3.file]

  Also while i am generating .mpd files via MP4Box i am getting below warning in console

  [DASH]: Files have non-proportional track layouts (320x240 vs 420x270) but sample size and aspect ratio match, assuming precision issue
  
  [DASH]: Files have non-proportional track layouts (320x240 vs 1024x576) but sample size and aspect ratio match, assuming precision issue
  
  [DASH]: Files have non-proportional track layouts (320x240 vs 1280x720) but sample size and aspect ratio match, assuming precision issue
  
  [DASH]: Files have non-proportional track layouts (320x240 vs 1920x1080) but sample size and aspect ratio match, assuming precision issue

  Whenever the video stops playing the chrome console has these logs

  Number of times the buffer has run dry: 25
  
  Apply STRONG to buffer rule.
  
  Quit switching bit rates.

  I don’t have any clue as to why the buffers run dry and it stops switching the bit rates.

  Anything that is predominantly wrong in the process ?