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• avformat/vobsub : fix invalid sub queue access while seeking.

  20 octobre 2013, par Clément Bœsch

  avformat/vobsub : fix invalid sub queue access while seeking.
  If there is only 1 stream and seek isn’t called with a specific stream
  
  index, we pick the first (and only) one.
  Regression since dbfe6110.
  Fixes CID1108591.
  

  • [DH] libavformat/mpeg.c

• Fill patterns

  26 avril 2008, par Mikko Koppanen — Imagick, PHP stuff

  My work life has been quite busy lately and I haven’t had a chance to sit down and blog. I have been touring around London and some parts of the northern England consulting and organizing some training here and there. Luckily I have had the chance to do some work on Imagick and the 2.2.0 beta release is getting closer. The internal structure was completely restructured and broken down into several smaller files. During this time Imagick was adapted to follow the PHP Coding Standards more closely. Still a work in progress

  I committed slightly modified version of this example to PHP Manual http://uk.php.net/manual/en/imagick.examples.php page a few days ago. The example illustrates using an image as a part of a named fill pattern. The fill pattern is used to annotate text but the named pattern could also be used to fill any shapes that allow fill to be specified (include circles, ellipses, rectangles, polygons etc etc). The code itself is pretty straight forward : Read the image, create the pattern and use the pattern as a fill.

  The ice formations image is from http://www.photoeverywhere.co.uk/west/winterholiday/slides/iceformations5679.htm.

  php

  < view plain text >

  1. < ?php
  2.  
  3. /* Create a new imagick object */
  4. $im = new Imagick( ’iceformations5679.JPG’ ) ;
  5.  
  6. /* Create imagickdraw object */
  7. $draw = new ImagickDraw() ;
  8.  
  9. /* Start a new pattern called "ice" */
  10. $draw->pushPattern( ’ice’ , 0 , 0 , 50 , 50 ) ;
  11.  
  12. /* Composite the image on the pattern */
  13. $draw->composite( Imagick: :COMPOSITE_OVER, 0, 0, 50, 50, $im ) ;
  14.  
  15. /* Close the pattern */
  16. $draw->popPattern() ;
  17.  
  18. /* Use the pattern called "ice" as the fill */
  19. $draw->setFillPatternURL( ’#ice’ ) ;
  20.  
  21. /* Set font size to 52 */
  22. $draw->setFontSize( 52 ) ;
  23.  
  24. /* Annotate some text */
  25. $draw->annotation( 5, 50, "Hello World !" ) ;
  26.  
  27. /* Create a new canvas and white image */
  28. $canvas = new Imagick() ;
  29. $canvas->newImage( 310, 70, "white" ) ;
  30.  
  31. /* Add black border around the resulting image */
  32. $canvas->borderImage( ’black’, 1, 1 ) ;
  33.  
  34. /* Draw the ImagickDraw on to the canvas */
  35. $canvas->drawImage( $draw ) ;
  36.  
  37. /* Set the format to PNG */
  38. $canvas->setImageFormat( ’png’ ) ;
  39.  
  40. /* Output the image */
  41. header( "Content-Type : image/png" ) ;
  42. echo $canvas ;
  43.  ?>

  And the result is here :

  

• ffmpeg splitting RGB and Alpha channels using filter

  29 juin 2012, par Dow

  I'm trying to use ffmpeg to split an input file into two separate files :

  1. An MP4 with only R,G and B channels
  2. An MP4 with the "extracted" A channel (a so-called Key clip, see http://ffmpeg-users.933282.n4.nabble.com/quot-Extracting-quot-Alpha-Channel-td3700227.html)

  I've managed to do both, but now I want to combine them into one single command. Here's what I do :

  ffmpeg -r $FPS -y -i input.flv -vcodec libx264 -vpre ipod640 -acodec libfaac -s 256x256 -r $FPS -filter_complex INSERT_FILTER_HERE rgb.mp4 alpha.mp4

  where INSERT_FILTER_HERE is :

  format=rgba, split [rgb_in][alpha_in];
  
  [rgb_in] fifo, lutrgb=a=minval [rgb_out];
  
  [alpha_in] format=rgba, split [T1], fifo, lutrgb=r=maxval:g=maxval:b=maxval, [T2] overlay [out];
  
  [T1] fifo, lutrgb=r=minval:g=minval:b=minval [T2]

  In short, I split the file into two streams, for the first stream, I "remove" the alpha channel, for the second stream, I extract a grayscale representation of the alpha channel. When I put this through graph2dot, it works fine, with a nullsink as output.

  However, when I run it in ffmpeg with -filter_complex, I get :

  ffmpeg version N-41994-g782763e Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Jun 28 2012 17:45:15 with gcc 4.6.3
  
    configuration: --enable-gpl --enable-nonfree --enable-pthreads --enable-filters --enable-libfaac --enable-libmp3lame --enable-libx264 --enable-libtheora --enable-libvpx --enable-postproc --enable-avfilter
  
    libavutil      51. 63.100 / 51. 63.100
  
    libavcodec     54. 29.101 / 54. 29.101
  
    libavformat    54. 11.100 / 54. 11.100
  
    libavdevice    54.  0.100 / 54.  0.100
  
    libavfilter     3.  0.100 /  3.  0.100
  
    libswscale      2.  1.100 /  2.  1.100
  
    libswresample   0. 15.100 /  0. 15.100
  
    libpostproc    52.  0.100 / 52.  0.100
  
  Input #0, flv, from 'input.flv':
  
    Metadata:
  
      audiodelay      : 0
  
      canSeekToEnd    : true
  
    Duration: 00:01:10.56, start: 0.000000, bitrate: 1964 kb/s
  
      Stream #0:0: Video: vp6a, yuva420p, 800x950, 1536 kb/s, 25 tbr, 1k tbn, 1k tbc
  
      Stream #0:1: Audio: mp3, 44100 Hz, stereo, s16, 128 kb/s
  
  [graph 0 input from stream 0:0 @ 0x2e4c6e0] w:800 h:950 pixfmt:yuva420p tb:1/30 fr:30/1 sar:0/1 sws_param:flags=2
  
  Output pad "default" for the filter "Parsed_lutrgb_3" of type "lutrgb" not connected to any destination

  Any ideas on how I make ffmpeg recognize that it has to write [rgb_out] to rgb.mp4 and [out] to alpha.mp3 ?

  Thanks in advance !