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• avformat/mxfdec : Use ff_data_to_hex() for data->hex conversion

  13 juin 2022, par Andreas Rheinhardt

  avformat/mxfdec : Use ff_data_to_hex() for data->hex conversion
  In this case it also stops pretending that the length of
  
  the output string is somehow checked (which is currently
  
  being done by using snprintf that is called with the amount
  
  of space needed instead of the amount of space actually available).
  Reviewed-by : Tomas Härdin <tjoppen@acc.umu.se>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavformat/mxfdec.c

• 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.

• applying a AlexaV3LogC pow expression in FFMPEG

  1er octobre 2018, par tankbusta

  Posted this to Video Stack as wel
  need help finding a way to bring 16bit RBG Exr’s into the right color space. In Nuke i would use the Alexav3LogC profile to do this but need a way to map this expression in FFMPEG. The expression i got from Nuke was as follows :

  x > 0.14996582 ? (pow(10,0, (x - 0.385537) / 0.2471896) - 0.0522720) /
  5.5555556 : (x - 0.092809) / 5.367655

  where would something like this go so that i can then apply the LUT from DI to being this footage into the correct color space

  im using FFMPEG with Python for this

  my FFMPEG python code is as follows :

  stream = ffmpeg.input(exr_wildcard_abspath, pattern_type='glob', framerate=24)
  
                  stream = ffmpeg.filter(stream,'scale', size='1920x1080', force_original_aspect_ratio='increase')
  
                  stream = ffmpeg.crop(stream, 197,0,1920,1080)
  
                  stream = ffmpeg.filter(stream,'format',pix_fmts='yuv420p')
  
                  stream = ffmpeg.output(stream, mov_dst,vcodec='prores_ks',profile='lt')
  
                  ffmpeg.run(stream)