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• Evolution #4080 : Raccourci puce : se débarasser de l’image

  1er octobre 2018

  Je vote pour le caractère
  https://unicode-table.com/fr/2023/

  Voici un test chez moi en local sur SPIP 3.2, la dist et Firefox Windows (bref 100% vanille)

• Large Panorama to Panning Video in FFMPEG

  7 octobre 2018, par Sogree

  I have been looking for a command line based solution for panning panorama’s like this : Large Panorama to Panning Video Based on that answer I’ve been experimenting with switches and formulas but they are a bit too complex for me (even after reading the ffmpeg command line help functions). What I would like to do :

  Pan an image from left to right. The input file is an PSD that has a large resolution (for example 3350x13140 pixels) but this is variable. So I would like ffmpeg to :

  1) Resize/scale the image to a set height of 1080 (so the height is set, but the width is flexible for the Pan) (is this step needed ??)

  2) Crop (and loop=1) the image to 1920x1080 (for me, combining scale and crop gives an error)

  3) But before starting the pan I would like it to wait for 2 seconds (so the most left part of the image would stand still for 2 seconds before panning)

  4) And after finishing the pan I would like it to wait for 2 seconds again (so the most right part of the image would stand still for 2 seconds before panning)

  5) Panning speed : Based on the width of the image (in this case 13140 pixels) I would like the panning speed to be 3,5 seconds per 1000 pixels. So in this case 46 seconds for the pan (and the end result (video length) would be 50 seconds (2 + 46 + 2).

  Only bullet 2 (with 1) I seem to be able to do.

  ffmpeg -loop 1 -framerate 60 -i in.psd -vf crop=1920:ih :’min((iw/10)*t,9*iw/10)’:0 -t 20 -c:v out.mp4

  So how should I alter the above options ? And in another posting this was listed :

  ffmpeg -loop 1 -r 60 -i in.psd -vf crop=1920:1080:n:0 -frames:v 11220 -pix_fmt yuv420p -preset fast -crf 25 out.mkv

  https://www.reddit.com/r/ffmpeg/comments/9051f1/i_want_to_pan_across_an_image_from_left_to_right/e2ukaah/

  But that command does not rescale the image (only pans the top (1920x1080) of the image).

  Maybe I need a combination of the two ? Or is using the zoompan command (with zoom set to off ?) a better option ?

• Piping ppm files to ffmpeg to create movie in c++

  17 mars 2018, par chasep255

  I want to create a movie of a zoom on the Mandelbrot set. To do this I want to create image data in the ppm format and then pipe it into ffmpeg using popen. The following command works if I first save the ppm to my disc and then run ffmpeg through the terminal.

  ffmpeg -i out.ppm -r 1/5 out.mp4

  Here is what I am trying to do in code.

  FILE* p = popen("ffmpeg -i /dev/stdin -r 1/5 out.mp4", "w");
  
  ppm_pipe(p, pix_buffers[0], w, h);
  
  fclose(p);
  
  ...
  
  void ppm_pipe(FILE* f, unsigned char* pix, int w, int h)
  
  {
  
      assert(fprintf(f, "P6 %d %d 255\n", w, h) > 0);
  
      size_t sz = 3 * (size_t)w * (size_t)h;
  
      assert(fwrite(pix, 1, sz, f) == sz);
  
  }

  I get the following error message.

  ffmpeg version 2.5.8-0ubuntu0.15.04.1 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 4.9.2 (Ubuntu 4.9.2-10ubuntu13)
  
    configuration: --prefix=/usr --extra-version=0ubuntu0.15.04.1 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --shlibdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --enable-shared --disable-stripping --enable-avresample --enable-avisynth --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libshine --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libwavpack --enable-libwebp --enable-libxvid --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzvbi --enable-libzmq --enable-frei0r --enable-libvpx --enable-libx264 --enable-libsoxr --enable-gnutls --enable-openal --enable-libopencv --enable-librtmp --enable-libx265
  
    libavutil      54. 15.100 / 54. 15.100
  
    libavcodec     56. 13.100 / 56. 13.100
  
    libavformat    56. 15.102 / 56. 15.102
  
    libavdevice    56.  3.100 / 56.  3.100
  
    libavfilter     5.  2.103 /  5.  2.103
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  /dev/stdin: Invalid data found when processing input