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• avcodec/snowenc : add intra_penalty AVOption

  9 mai 2015, par Michael Niedermayer

  avcodec/snowenc : add intra_penalty AVOption
  This allows favoring intra or inter blocks by a user specified amount.
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/snow.h
  • [DH] libavcodec/snowenc.c

• Revision 53ff43adc3 : Prunes out full-rd computation based on modeled rd Adds a speed feature to elim

  9 juillet 2013, par Deb Mukherjee

  Changed Paths :
   Modify /vp9/common/vp9_blockd.h

  
   Modify /vp9/encoder/vp9_onyx_if.c

  
   Modify /vp9/encoder/vp9_onyx_int.h

  
   Modify /vp9/encoder/vp9_rdopt.c

  
  
  Prunes out full-rd computation based on modeled rd

  Adds a speed feature to eliminate full-rd computation if the modeled
  rd or rd based on a different parameter in the same mode is already
  a lot larger than the best rd yet.

  Specifically, only search the sharp and smooth filters if the modeled
  rd cost based on the regular filter is within a certain factor of the
  best rd cost so far. Also, skip full-rd computation of non splitmv
  inter modes if the modeled rd cost based on pred error is within the
  same factor of the best rd cost so far.

  Also adds some enhancements in the rd search for splitmv mode to
  speed things up by early breakouts. Negligible impact on performance.

  Resuts on derfraw300 :
  psnr : -0.013% with the splitmv enhancements, -0.24% with the rd
  breakout feature on.
  speedup : 6% with splitmv enhancements, 20% with also residual breakout
  (tested on football sequence at 600 Kbps)

  Change-Id : I37abc308ea9f110c1679ce649b6a7e73ab1ad5fc

• How to losslessly compress a sequence of slowly-changing images into a video ?

  26 juillet 2023, par Claude C

  I have a sequence of jpeg images captured like a timelapse, with the same dimension and changing slowly in order. I want to compress the size of the whole sequence while still able to recover each individual image with their raw pixel information unchanged.

  


  I googled and found that a possible solution is to compress it into a video, which exploits the strong temporal correlation (inter-frame redundancy) between consecutive frames, as suggested here. I tried ffmpeg libx264 but none of the option combinations seem to preserve frame quality and compress total size at the same time (-crf 0 keeps the quality but the size of the video is even larger than the input sequence).

  


  So my questions is,

  


  

  • What is the correct way to losslessly compress a sequence of slowly-changing images ?

  


  


  I can accept using softwares other than ffmpeg (as long as it is on windows or linux), doing color space conversion on raw images (if necessary). It is OK if a the compression is done without converting to videos. Thank you.