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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

  

• Seam carving

  9 juin 2010, 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

  

• Start of video is not labeled as "0" in QuickTime Video from GoPro

  26 mars 2020, par John Terragnoli

  I’m trying to combine four GoPro videos into a single video, and then rotate it 90 degrees. However, the time scales on the bottom of the videos are all wrong. The videos are 17 minutes and 42 second. But the beginning time is labeled as 5:15:20:32 and the ending time is 5:33:01:32. It just looks really weird and I’d like to fix it. After I use ffmpeg to rotate and concatenate the videos, the problem persists. Could it possibly be fixed with Exiftool ?

  ffmpeg -safe 0 -f concat -i list.txt -vcodec copy -acodec copy merged_videos.MP4

  ffmpeg -i input.mov -vf "transpose=1" output.mov

  Here is the exiftool information on one of the videos :

  File Name                       : GOPR3023.MP4
  
  Directory                       : .
  
  File Size                       : 3.7 GB
  
  File Modification Date/Time     : 2018:04:12 14:56:16-05:00
  
  File Access Date/Time           : 2020:03:25 12:17:18-05:00
  
  File Inode Change Date/Time     : 2020:03:25 17:57:04-05:00
  
  File Permissions                : rwxrwxrwx
  
  File Type                       : MP4
  
  File Type Extension             : mp4
  
  MIME Type                       : video/mp4
  
  Major Brand                     : MP4 v1 [ISO 14496-1:ch13]
  
  Minor Version                   : 2013.10.18
  
  Compatible Brands               : mp41
  
  Movie Data Size                 : 4001979951
  
  Movie Data Offset               : 28
  
  Movie Header Version            : 0
  
  Create Date                     : 2018:04:12 14:38:32
  
  Modify Date                     : 2018:04:12 14:38:32
  
  Time Scale                      : 60000
  
  Duration                        : 0:17:42
  
  Preferred Rate                  : 1
  
  Preferred Volume                : 100.00%
  
  Preview Time                    : 0 s
  
  Preview Duration                : 0 s
  
  Poster Time                     : 0 s
  
  Selection Time                  : 0 s
  
  Selection Duration              : 0 s
  
  Current Time                    : 0 s
  
  Next Track ID                   : 6
  
  Firmware Version                : HD5.03.02.51.00
  
  Lens Serial Number              : NAH6092300301117
  
  Camera Serial Number Hash       : 34676f2cdf49b86a1514817a93377bf7
  
  Track Header Version            : 0
  
  Track Create Date               : 2018:04:12 14:38:32
  
  Track Modify Date               : 2018:04:12 14:38:32
  
  Track ID                        : 1
  
  Track Duration                  : 0:17:42
  
  Track Layer                     : 0
  
  Track Volume                    : 0.00%
  
  Image Width                     : 1920
  
  Image Height                    : 1080
  
  Graphics Mode                   : srcCopy
  
  Op Color                        : 0 0 0
  
  Compressor ID                   : avc1
  
  Source Image Width              : 1920
  
  Source Image Height             : 1080
  
  X Resolution                    : 72
  
  Y Resolution                    : 72
  
  Compressor Name                 : GoPro AVC encoder
  
  Bit Depth                       : 24
  
  Color Representation            : nclx 1 1 1
  
  Video Frame Rate                : 59.94
  
  Time Code                       : 3
  
  Balance                         : 0
  
  Audio Format                    : mp4a
  
  Audio Channels                  : 2
  
  Audio Bits Per Sample           : 16
  
  Audio Sample Rate               : 48000
  
  Text Font                       : Unknown (21)
  
  Text Face                       : Plain
  
  Text Size                       : 10
  
  Text Color                      : 0 0 0
  
  Background Color                : 65535 65535 65535
  
  Font Name                       : Helvetica
  
  Other Format                    : tmcd
  
  Warning                         : [minor] The ExtractEmbedded option may find more tags in the movie data
  
  Matrix Structure                : 1 0 0 0 1 0 0 0 1
  
  Media Header Version            : 0
  
  Media Create Date               : 2018:04:12 14:38:32
  
  Media Modify Date               : 2018:04:12 14:38:32
  
  Media Time Scale                : 60000
  
  Media Duration                  : 0:17:42
  
  Handler Class                   : Media Handler
  
  Handler Type                    : NRT Metadata
  
  Handler Description             : GoPro SOS
  
  Gen Media Version               : 0
  
  Gen Flags                       : 0 0 0
  
  Gen Graphics Mode               : srcCopy
  
  Gen Op Color                    : 0 0 0
  
  Gen Balance                     : 0
  
  Meta Format                     : fdsc
  
  Image Size                      : 1920x1080
  
  Megapixels                      : 2.1
  
  Avg Bitrate                     : 30.1 Mbps
  
  Rotation                        : 0

  Part 2
  There is a pretty obvious "stutter" at the 17:42 mark where the two clips are combined. I’ve tried using ffmpeg and iMovie, but both give the same results. The GoPro broke up the event into multiple clips on it’s own so it seems weird that there would be any information missing. Is there any way to get rid of this stutter ?

  Thanks !