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• HEVC File bigger after converting from h264

  26 janvier 2019, par Aaroknight

  I’m currently working an an automated Python script for indexing and converting all my movies and episodes with ffmpeg. I use subprocess.call() for running the ffmpeg command and tested this command with some movies. As expected the big h264 files were converted to merely one third of what they used to have.

  But now that I was testing the method I found that a converted episode (about 400MB in h264) had over 1,6GB in hevc. I have absolutely no idea why the new file would be that much bigger in hevc.
  This is my code :

  def convert(path):
  
      outvid = path.strip(".mkv") + "h265.mkv"
  
  
  
      cmd = ["ffmpeg", "-i", path, "-map", "0", "-map_metadata", "0", "-map_chapters", "0", "-c:v", "libx265",
  
             "-c:a", "copy", "-c:s", "copy", "-preset", "ultrafast", "-x265-params", "lossless=1", outvid]
  
      subprocess.call(cmd)
  
  
  
  convert("/Volumes/2TB/Black Butler/Season 1/Black Butler S01E01.mkv")

  I don’t have that much experience with ffmpeg, nor with subprocess. This is one of my first bigger projects. I hope someone can tell me what the problem might be.

  UPDATE
  Problem applies only for small video files. I now just check for the file size and skip the small files. Wouldn’t have made much of a difference anyway.

  

• ffmpeg datascope filter : How does it works ?

  25 octobre 2022, par tony

  I'm trying to see how the datascope filter is displaying the color values for a black and white image. I was expecting to see a part of the image with 0xfff and one with 0x000 value,
instead I obtained only the 0xfff for white

  


  ffmpeg \
-f lavfi -i color=white:100x100 \
-f lavfi -i color=black:100x100 \
-lavfi '[0:v][1:v]hstack[out]' \
-map [out] \
-frames 1 \
blackAndWhite.png ; \


ffmpeg \
-i blackAndWhite.png \
-vf 'datascope' \
data.png


  


  what am I seeing ?


  


• Replacing detected object in a frame with an image.(imageProcessing)

  29 juin 2015, par Kiran Kumar Dash

  Overview :

  I am working on a video creation project. The technology I am using are : imageMagick, php, ffmpeg.

  Current Status :

  Currently the project is able to create videos using images and texts and few basic transitions. The way I am doing it is using imagemagick to create gif using input images(with transition effects in them) and then converting all gifs to videos and atlast concatenating the video together.

  Next Move (My question) :

  I am now set to take it to the next level. So, what I am having is a video(1920x1080) with some white frames(1280x720) that keeps shifting in each frame. I want to replace those white frames appearing in some frames of the video with some images(1280x720) that I wish to use. Please see the image here and you will get an idea : These are just two frames from my video. If you can see carefully the images are shifting(white space is not constant).

  

  

  Expectation :

  So, I want to fill those white space with one of my own image. If the case would have been for only one frame I could have used ffmpeg to overlay image on the exact width and height. But here the white space is not fixed and keeps shifting in all the frames and there are a lot of frames. So, I am looking for something like opencv or some other technology that can be used for object detection in a video or in a set of frames and replace the detected area with some other image.

  I just need a kick. So, if anyone has already worked on something like this just suggest me what technology can I use. Thanks in advance.