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• Seam carving

  13 février 2008, par Mikko Koppanen — Imagick, PHP stuff

  Today I was reading trough the ImageMagick ChangeLog and noticed an interesting entry. “Add support for liquid rescaling”. I rushed to check the MagickWand API docs and there it was : MagickLiquidRescaleImage ! After about ten minutes of hacking the Imagick support was done. Needless to say ; I was excited

  For those who don’t know what seam carving is check the demo here. More detailed information about the algorithm can be found here : “Seam Carving for Content-Aware Image Resizing” by Shai Avidan and Ariel Shamir

  To use this functionality you need to install at least ImageMagick 6.3.8-2 and liblqr. Remember to pass –with-lqr to ImageMagick configuration line. You can get liblqr here : http://liblqr.wikidot.com/. The Imagick side of the functionality should appear in the CVS today if everything goes as planned.

  Here is a really simple example just to illustrate the results of the operation. The parameters might be far from optimal (didn’t do much testing yet). The original dimensions of image are 500×375 and the resulting size is 500×200.

  Update : the functionality is pending until license issues are solved.

  php

  < view plain text >

  1. < ?php
  2.  
  3. /* Create new object */
  4. $im = new Imagick( ’test.jpg’ ) ;
  5.  
  6. /* Scale down */
  7. $im->liquidRescaleImage( 500, 200, 3, 25 ) ;
  8.  
  9. /* Display */
  10. header( ’Content-Type : image/jpg’ ) ;
  11. echo $im ;
  12.  
  13.  ?>

  The original image by flickr/jennconspiracy

  

  And the result :

  

  Update. On kenrick’s request here is an image which is scaled down to 300×300

  

• python call of ffmpeg misses target file parameter

  2 décembre 2016, par Fred

  I’m writing a python GUI for ffmpeg. When calling ffmpeg via subprocess it runs fine as long as the command is like

  subprocess.Popen([ffmpeg_converter,
  
          '-i',file,
  
          target_file
  
          ])

  But when I do the same call with ffmpeg arguments it fails with
  "At least one output file must be specified" :

  option_string = '-q:a 4'
  
  subprocess.Popen([ffmpeg_converter,
  
          '-i',file,
  
          option_string,
  
          target_file
  
          ])

  It even recognizes the options but does not see the target file. I even replaced the actual target file with someting simple like "test.mp3" but still the same error. Any ideas ? (I’m on windows with python 3.3.)

  The complete console output is :

      ffmpeg version N-57781-g0610d6e Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Nov  1 2013 18:01:35 with gcc 4.8.2 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
  
  le-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --ena
  
  ble-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libsp
  
  eex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavp
  
  ack --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  
    libavutil      52. 49.100 / 52. 49.100
  
    libavcodec     55. 40.101 / 55. 40.101
  
    libavformat    55. 20.105 / 55. 20.105
  
    libavdevice    55.  5.100 / 55.  5.100
  
    libavfilter     3. 90.100 /  3. 90.100
  
    libswscale      2.  5.101 /  2.  5.101
  
    libswresample   0. 17.104 /  0. 17.104
  
    libpostproc    52.  3.100 / 52.  3.100
  
  Trailing options were found on the commandline.
  
  Input #0, flac, from 'c:\script\python\testdata\source\01. Es geht los.flac':
  
    Metadata:
  
      ARTIST          : Olivia Trummer Trio
  
      TITLE           : Es geht los
  
      ALBUM           : Westwind
  
      DATE            : 2008
  
      track           : 01
  
      GENRE           : Jazz
  
      COMMENT         : EAC FLAC -8
  
    Duration: 00:06:27.25, bitrate: 834 kb/s
  
      Stream #0:0: Audio: flac, 44100 Hz, stereo, s16
  
  At least one output file must be specified

• Encode video for streaming in Android using FFmpeg

  16 décembre 2013, par Timofey

  UPD : I guess I found the problem. For some reason, 1800x1080 video aren't playing while same vid resized to 800x480 with same set of encoding settings is working just fine.
  So the question is : why I couldn't play video with res. bigger than the size of my screen ?

  I'm trying to build a simple video-streaming app for android.

  For the purpose of testing, I used this video http://www.quirksmode.org/html5/videos/big_buck_bunny.mp4, and it worked fine.

  However I miserably failed trying to prepare my own video for streaming.
  I'm using FFmpeg & libx264 with the following line (last attempt) :

  ffmpeg -i <input /> -c:v libx264 -profile:v baseline -c:a aac -strict experimental <output>
  
  </output>

  Then I passed the output to qt-faststart, as some people suggested... No effect.

  Here is the output of ffmpeg -i for my video :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'bbb_audio_h264.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      creation_time   : 2008-05-27 18:40:35
  
      encoder         : Lavf53.32.100
  
    Duration: 00:00:10.04, start: 0.000000, bitrate: 5048 kb/s
  
      Stream #0:0(eng): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1920x1080, 4605 kb/s, 24 fps, 24 tbr, 24 tbn, 48 tbc
  
      Metadata:
  
        creation_time   : 2008-05-27 18:40:35
  
        handler_name    : VideoHandler
  
      Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, 5.1, s16, 440 kb/s
  
      Metadata:
  
        creation_time   : 2008-05-27 18:40:35
  
        handler_name    : 

  And for the working one :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'big_buck_bunny.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 1
  
      compatible_brands: mp42avc1
  
      creation_time   : 2010-02-09 01:55:39
  
    Duration: 00:01:00.09, start: 0.000000, bitrate: 733 kb/s
  
      Stream #0:0(eng): Audio: aac (mp4a / 0x6134706D), 22050 Hz, stereo, s16, 65 kb/s
  
      Metadata:
  
        creation_time   : 2010-02-09 01:55:39
  
        handler_name    : Apple Sound Media Handler
  
      Stream #0:1(eng): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 640x360, 612 kb/s, 23.96 fps, 24 tbr, 600 tbn, 1200 tbc
  
      Metadata:
  
        creation_time   : 2010-02-09 01:55:39
  
        handler_name    : Apple Video Media Handler
  
      Stream #0:2(eng): Data: none (rtp  / 0x20707472)
  
      Metadata:
  
        creation_time   : 2010-02-09 01:55:39
  
        handler_name    : hint media handler
  
      Stream #0:3(eng): Data: none (rtp  / 0x20707472)
  
      Metadata:
  
        creation_time   : 2010-02-09 01:55:39
  
        handler_name    : hint media handler