Recherche avancée

Sur d’autres sites (8453)

• Capturing Video with 1:1 aspect ratio on Android

  30 septembre 2016, par Nikhil Mathew

  I am trying to develop an android app that would record a 15sec 640x640 video using MediaRecorder, extract all frames using ffmpeg, apply some artistic filters using gpuimage and then combine the frames back to a video using ffmpeg.

  I’m facing problem in recording a video of resolution 640x640. (Instagram android app does this)

  I tried using MediaRecorder’s setVideoSize(640, 640) and the output video is 640x640 but the video looks like a 640x480 video stretched vertically to make it 640x640. I guess that’s because 640x640 is not a resolution returned by the supported video capture resolution list of the device. Is there any way to tell media recorder to maintain aspect ratio while doing such scaling so that I get a video that was scaled from 640x480 to 640x640 by cropping width wise instead of stretching height wise ?

• Ruby on Rails : FFMPEG fails after upgrade Mountain Lion to Mavericks

  25 octobre 2013, par CristianOrellanaBak

  yesterday I upgrade my OS fom Mountain Lion to Mavericks and all goes well until recently.

  We are developing a Ruby on Rails v3.2.13 application for manage videos (only MP4), which worked fine until yesterday with Mountain Lion. Today (with Mavericks) I try to upload a video but get the following error in the console :

  Running transcoding...
  
  ffmpeg -y -i /Users/ME/Documents/workspace/rails/rails3-devise/public/uploads/tmp/1382653048-574-3293/thumb_con02_apv_revisado_1280x720.mp4 -ss 0 -s 180x110 -vframes 1 -f image2 -aspect 1.6363636363636365 /Users/Me/Documents/workspace/rails/rails3-devise/public/uploads/tmp/1382653048-574-3293/thumb_con02_apv_revisado_1280x720.png
  
  
  
  Transcoding of /Users/Me/Documents/workspace/rails/rails3-devise/public/uploads/tmp/1382653048-574-3293/thumb_con02_apv_revisado_1280x720.mp4 to /Users/Me/Documents/workspace/railspublic/uploads/tmp/1382653048-574-3293/thumb_con02_apv_revisado_1280x720.png succeeded
  
  
  
  Running transcoding...
  
  ffmpeg -y -i /Users/Me/Documents/workspace/rails/public/uploads/tmp/1382653048-574-3293/thumb_con02_apv_revisado_1280x720.mp4 -ss 0 -s 180x110 -vframes 1 -f image2 -aspect 1.6363636363636365 /Users/Me/Documents/workspace/rails/rails3-devise/public/uploads/tmp/1382653048-574-3293/thumb_con02_apv_revisado_1280x720.png
  
  
  
  Failed encoding...
  
  ffmpeg -y -i /Users/Me/Documents/workspace/rails/tmp/1382653048-574-3293/thumb_con02_apv_revisado_1280x720.mp4 -ss 0 -s 180x110 -vframes 1 -f image2 -aspect 1.6363636363636365 /Users/Me/Documents/workspace/rails/uploads/tmp/1382653048-574-3293/thumb_con02_apv_revisado_1280x720.png
  
  
  
  ffmpeg version 1.2.1 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Sep 28 2013 20:09:07 with Apple LLVM version 4.2 (clang-425.0.24) (based on LLVM 3.2svn)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/1.2.1 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables --enable-avresample --enable-vda --cc=cc --host-cflags= --host-ldflags= --enable-libx264 --enable-libfaac --enable-libmp3lame --enable-libxvid --enable-libfreetype --enable-libtheora --enable-libvorbis --enable-libvpx --enable-librtmp --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-aacenc --enable-libass --enable-ffplay --enable-libspeex --enable-libschroedinger --enable-libfdk-aac --enable-libopus --enable-frei0r --enable-libopenjpeg --extra-cflags='-I/usr/local/Cellar/openjpeg/1.5.1/include/openjpeg-1.5 '
  
    libavutil      52. 18.100 / 52. 18.100
  
    libavcodec     54. 92.100 / 54. 92.100
  
    libavformat    54. 63.104 / 54. 63.104
  
    libavdevice    54.  3.103 / 54.  3.103
  
    libavfilter     3. 42.103 /  3. 42.103
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  2.100 / 52.  2.100
  
  [mp3 @ 0x7fd493820c00] Format mp3 detected only with low score of 1, misdetection possible!
  
  [mp3 @ 0x7fd49380a000] Header missing
  
      Last message repeated 1 times
  
  [mp3 @ 0x7fd493820c00] decoding for stream 0 failed
  
  [mp3 @ 0x7fd493820c00] Could not find codec parameters for stream 0 (Audio: mp2, 0 channels, s16p): unspecified frame size
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  [mp3 @ 0x7fd493820c00] Estimating duration from bitrate, this may be inaccurate
  
  /Users/Me/Documents/workspace/rails/tmp/1382653048-574-3293/thumb_con02_apv_revisado_1280x720.mp4: could not find codec parameters
  
  
  
  Errors: no output file created.

  I reinstall the dependencies of ffmpeg, but the problem persists.

  Any ideas or suggestions to solve the problem ?
  Thank you very much !

  EDIT NOTE : I notice this when run brew upgrade :

  ==> Upgrading ffmpeg
  
  ==> Installing ffmpeg dependency: libass
  
  Error: libass dependency fontconfig was built with the following
  
  C++ standard library: libstdc++ (from clang)
  
  
  
  This is incompatible with the standard library being used
  
  to build libass: libc++ (from clang)
  
  
  
  Please reinstall fontconfig using a compatible compiler.
  
  hint: Check https://github.com/mxcl/homebrew/wiki/C++-Standard-Libraries

• 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