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• lavfi : add ICC profile support via lcms2

  9 avril 2022, par Niklas Haas

  lavfi : add ICC profile support via lcms2
  This introduces an optional dependency on lcms2 into FFmpeg. lcms2 is a
  
  widely used library for ICC profile handling, which apart from being
  
  used in almost all major image processing programs and video players,
  
  has also been deployed in browsers. As such, it's both widely available
  
  and well-tested.
  Add a few helpers to cover our major use cases. This commit merely
  
  introduces the helpers (and configure check), even though nothing uses
  
  them yet.
  It's worth pointing out that the reason the cmsToneCurves for each
  
  AVCOL_TRC are cached inside the context, is because constructing a
  
  cmsToneCurve requires evaluating the curve at 4096 (by default) grid
  
  points and constructing a LUT. So, we ideally only want to do this once
  
  per curve. This matters for e.g. ff_icc_profile_detect_transfer, which
  
  essentially compares a profile against all of these generated LUTs.
  
  Re-generating the LUTs for every iteration would be unnecessarily
  
  wasteful.
  The same consideration does not apply to e.g. cmsCreate*Profile, which
  
  is a very lightweight operation just involving struct allocation and
  
  setting a few pointers.
  The cutoff value of 0.01 was determined by experimentation. The lowest
  
  "false positive" delta I saw in practice was 0.13, and the largest
  
  "false negative" delta was 0.0008. So a value of 0.01 sits comfortaby
  
  almost exactly in the middle.
  Signed-off-by : Niklas Haas <git@haasn.dev>
  

  • [DH] configure
  • [DH] libavfilter/fflcms2.c
  • [DH] libavfilter/fflcms2.h

• avcodec/mpegvideo_enc : Ignore ICC profile size when not MJPEG

  11 avril 2022, par Andreas Rheinhardt

  avcodec/mpegvideo_enc : Ignore ICC profile size when not MJPEG
  MJPEG is the only mpegvideo-based encoder making use of it.
  
  Fixes linking failures in case mpegvideo_enc.c is compiled
  
  with AMV, LJPEG and MJPEG encoders disabled.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/mpegvideo_enc.c

• Writing a video with H.264 in OpenCV with High profile from a high profile mp4 file

  7 avril 2022, par dinesh47

  I have High profile mp4 video i am using opencv to overlay some text inside but output.mp4 is writing in simple profile format. is there a way to write it in high profile
I am using opencv 3.4.16 latest

  


  Devlopment platform is : Windows C++ VS2019

  


  


  VideoWriter videocc(destFile, VideoWriter::fourcc('M', 'P', '4', 'V'), fps, cv::Size(width, height)) ;

  


  


  I have tried X264 , H264 ,AVC1 in fourcc, But not writing in high profile

  


  Is there a way or sample available to generate high profile output video format

  


  please find the following attachment for main profile coded problem