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• FFMPEG - Add (white, color-less, analog) grain to the video without desaturating video itself

  2 décembre 2018, par dd_code

  I am working on old videos where I am basically converting them to HVEC and sharpening, so i.e. my command can look like this

  .\ffmpeg.exe -i F:\file.mkv -vf unsharp=3:3:1.5 -c:v hevc_nvenc -qp 27 -a:c copy file_new.mkv

  inherent problem with this is, of course that with reducing bitrate and sharpening every now and then I can notice some nasty artifacts around the edges and on at plain-color objects.

  I noticed with some older, many times remastered movies/series that they have quite a lot of grain in the video, so I was thinking - what if I add grain and help it to mask the compression and sharpening artifacts ?

  After bit of searching I got to
  https://ffmpeg.org/ffmpeg-filters.html#noise
  and now I am using this command

  .\ffmpeg.exe -i F:\file.mkv -vf unsharp=3:3:1.5,noise=alls=14:allf=t+u -c:v hevc_nvenc -qp 30 -a:c copy file_new.mkv

  however this has one big problem, it is merely a digital RGB noise, is there a way to make it desaturated, analog-ish ? I tried adding h=s=0, however this is applying 0 saturation to the video track as a whole. Is there an effect which would achieve this or is there a way that I can reduce the saturation only of the very effect which then gets to "overlay" the video track, so the track would not be touched ?

• JavaCV FFmpegFrameRecorder Video output reddish color

  14 juin 2016, par Diego Perozo

  I am trying to make a video .mp4 file out of a group of images using FFmpegFrameRecorder as a part of a bigger program, so I set up a test project in which I try to make a video out of 100 instances of the same frame at 25fps. The program seems to work. However, every time I run it the image seems to be reddish. As if a red filter had been applied to it.

  Here’s the code snippet :

  public static void main(String[] args) {
  
      File file = new File("C:/Users/Diego/Desktop/tc-images/image0.jpg");
  
      BufferedImage img = null;
  
      try {
  
          img = ImageIO.read(file);
  
      } catch (IOException e1) {
  
          e1.printStackTrace();
  
      }
  
      IplImage image = IplImage.createFrom(img); 
  
      FFmpegFrameRecorder recorder = new FFmpegFrameRecorder("C:/Users/Diego/Desktop/tc-images/test.mp4",1920,1080); 
  
      try { 
  
      recorder.setVideoCodec(13);
  
      recorder.setFormat("mp4");
  
      recorder.setPixelFormat(0);
  
      recorder.setFrameRate(25);
  
      recorder.start(); 
  
      for (int i=0;i<100;i++){ 
  
      recorder.record(image); 
  
      } 
  
      recorder.stop(); 
  
      } 
  
      catch (Exception e){ 
  
      e.printStackTrace(); 
  
      } 
  
  }

  I’d appreciate it if anybody told me what’s wrong. Thanks in advance for any help.

• 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 :) !