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• ffmpeg neighbor resize giving distortion when resizing video game footage. 2x2 pixels converted to 3x3 don't hold their color and are pixelated

  12 avril 2020, par PixelFrustated

  Here is my ffmpeg code :

  



  ffmpeg -i C :\FFMPEG\bin\input.mp4 -vf "scale=-2:1080" -sws_flags neighbor -c:v libx264 -crf 0 -preset Slow -c:a copy -b:a 320k C :\FFMPEG\bin\VIDEO2_1080p.mp4

  



  I'm converting a 720p video to 1080p. The game is 2x2 pixels and when I do the conversion they should be flat 3x3 pixels but instead they come out with slight miscolors on the insides between the pixels and their color is slightly off.

  



  Can anyone help me figure out why this warped ?

  



  Pixels on the left are 2x2 and are converted to the pixels on the right.

  



  Instead of 2x2 expanding out to a 3x3 it takes a weird blend going vertical but the horizontal pixels are just fine.

  


• avfilter/buffersrc : promote unspecified color metadata

  12 janvier 2024, par Niklas Haas

  avfilter/buffersrc : promote unspecified color metadata
  Currently, this only affects untagged RGB/XYZ/Gray, which get forced to
  
  their corresponding metadata before entering the filter graph. The main
  
  justification for this change, however, is the planned ability to add
  
  automatic promotion of unspecified yuv to mpeg range yuv.
  Notably, this change will never allow accidentally cross-promoting
  
  unspecified to jpeg or to a specific YUV matrix, since that is still
  
  bound by the constraints of YUV range negotiation as set up by
  
  query_formats.
  

  • [DH] libavfilter/buffersrc.c
  • [DH] tests/ref/fate/rgb24-mkv

• What is the ideal image format extraction for YUV color space and lossless compression from mxf video format using ffmpeg

  15 février 2016, par DragonDance27

  I would like to be able to work on frames from an .mxf video file. The image format of the video is JPEG 2000, using a YUV color space with 4:2:2 subsampling and lossless compression.

  My intentions are to extract frames from this video using ffmpeg. Extracted frames would then be processed in Matlab (at the moment I’m interested in performing colorization).

  I want to extract the frames with as minimal data loss as possible and I would like to work in the YUV color space. I understand PNG involves a lossless process, but only involves the RGB color space - so not an option.

  I think I can extract jpeg2000 frames in the YUV color space, but I’m not sure if I’m losing data from the compression process. I attempted the following code in ffmpeg :

  ffmpeg -i video.mxf -r 1/5 out%03d.jp2

  ... however, the extracted jp2 files are unreadable in various software, including HiView which is a specialised JPEG 2000 software.

  Quesiton 1 : Is this jpeg 2000 extraction method lossless ? What am I doing wrong ?

  I also considered extracting the images in the tiff format where I can achieve the YUV and lossless requirements. I attempted the following code in ffmpeg :

  ffmpeg -i video.mxf -vcodec tiff f%10d.tif

  ... however, the extracted tiff files are unreadable in software such as paint, paint.net and windows photo viewer.

  Question 2 : Is this tiff extraction method correct ? What am I doing wrong ?

  Question 3 : What is an ideal image format that covers my YUV and lossless requirements ?