Recherche avancée

Sur d’autres sites (3961)

• Loop through images, detect if contains color, put in subfolder

  16 avril 2022, par Samo

  I have two kinds of images in my folder : One is all black, the other one is black with yellow (#f8fa27). I am trying to put all the images with yellow colour in a subfolder. But I don't know how this is applicable.

  


  I would like to implement this with ImageMagick or FFMPEG. If possible, shell is redundant and I would like the loop via CMD. If you happen to know of another option that also works, that's no problem either.

  


  I've read about https://imagemagick.org/script/fx.php but I don't know how to apply it with my poor skills.

  


  Edit for now I managed to fix it with python (shitty code but it works)

  


  import cv2
import os
import glob

#check if extension is png
for filename in glob.glob("*.png"):
    #return to folder where all images are saved
    os.chdir('C:/Users/.../.../images')
    #make image black and white
    image = cv2.imread(filename, 0)
    #if image is fully black
    if cv2.countNonZero(image) == 0:
        print ("Black image, skipped")
    else:
        #colored image
        print ("Colored image")
        #restore true colors (rgb in my case, check wiki)
        image = cv2.imread(filename, cv2.COLOR_BGR2RGB)
        #folder to save colored images
        os.chdir(os.getcwd()+"/yellow")
        #save image to subfolder
        cv2.imwrite(filename,image)


  


  Thank you :) !

  


• vf_paletteuse : fix color cache lookup for Bayer dithering mode.

  10 janvier 2022, par Rudolf Polzer

  vf_paletteuse : fix color cache lookup for Bayer dithering mode.
  To trigger this bug, use `paletteuse=dither=bayer:bayer_scale=0` ; you will see
  
  that adjacent pixel lines will use the same dither pattern, instead of being
  
  shifted from each other by 32 units (0x20).
  One way to demostrate the bug is :
  $ convert -size 64x256 gradient:black-white -rotate 270 grad.png
  
  $ echo 'P2 2 1 255 0 255' > bw.pnm
  
  $ ffmpeg -i grad.png -filter_complex 'movie=bw.pnm,scale=256x1[bw] ; [0:v][bw]paletteuse=dither=bayer:bayer_scale=0' gradbw.png
  Previously : https://www.rm.cloudns.org/img/uploaded/0bd152c11b9cd99e5945115534b1bdde.png
  
  Now :        https://www.rm.cloudns.org/img/uploaded/89caaa5e36c38bc2c01755b30811f969.png
  This was caused by passing inconsistent color vs (a,r,g,b) parameters to
  
  color_get(), and NBITS being 5 meaning actually hitting the same cache node
  
  does happen in this case, but ONLY if bayer_scale is zero.
  The fix is passing the correct color value to color_get().
  Also added a previous-failing FATE test ; image comparison of the first frame :
  Previously : https://www.rm.cloudns.org/img/uploaded/d0ff9db8d8a7d8a3b8b88bbe92bf5fed.png
  
  Now :        https://www.rm.cloudns.org/img/uploaded/a72389707e719b5cd1c58916a9e79ca8.png
  (on this less synthetic test image, the bug basically causes noise from cache
  
   hits vs misses)
  Tested : FATE passes, which exercises this filter but at the default bayer_scale.
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  

  • [DH] libavfilter/vf_paletteuse.c
  • [DH] tests/fate/filter-video.mak
  • [DH] tests/ref/fate/filter-paletteuse-bayer0

• avdevice/dshow : discover source color range/space/etc

  21 décembre 2021, par Diederick Niehorster

  avdevice/dshow : discover source color range/space/etc
  Enabled discovering a DirectShow device's color range, space, primaries,
  
  transfer characteristics and chroma location, if the device exposes that
  
  information. Sets them in the stream's codecpars.
  Co-authored-by : Valerii Zapodovnikov <val.zapod.vz@gmail.com>
  
  Signed-off-by : Diederick Niehorster <dcnieho@gmail.com>
  
  Reviewed-by : Roger Pack <rogerdpack2@gmail.com>
  

  • [DH] libavdevice/dshow.c