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• avcodec/mips : Improve hevc bi weighted copy, hz and vt mc msa functions

  27 octobre 2017, par Kaustubh Raste

  avcodec/mips : Improve hevc bi weighted copy, hz and vt mc msa functions
  Pack the data to half word before clipping.
  
  Use immediate unsigned saturation for clip to max saving one vector register.
  Signed-off-by : Kaustubh Raste <kaustubh.raste@imgtec.com>
  
  Reviewed-by : Manojkumar Bhosale <Manojkumar.Bhosale@imgtec.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/mips/hevc_mc_biw_msa.c

• aarch64 : vp9itxfm : Reorder iadst16 coeffs

  31 décembre 2016, par Martin Storsjö

  aarch64 : vp9itxfm : Reorder iadst16 coeffs
  This matches the order they are in the 16 bpp version.
  There they are in this order, to make sure we access them in the
  
  same order they are declared, easing loading only half of the
  
  coefficients at a time.
  This makes the 8 bpp version match the 16 bpp version better.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavcodec/aarch64/vp9itxfm_neon.S

• Reducing frames with ffmpeg leads to massive video size reaction - what´s wrong ?

  9 juin 2023, par Katharina

  I am working on a project in which I need to

  


  -transform many videos from .h264 format to .mp4

  


  -cut them after 1 hour duration

  


  -reduce the framerate from 60 fps to 30 fps

  


  Up to now, I came up with following :

  


  Convert :

  


  for %a in ("*.h264") do ffmpeg -framerate 60 -fflags +genpts -i "%a" -vcodec copy -acodec copy "%~na_Conv.mp4


  


  Cut :

  


  for %a in ("*.mp4") do ffmpeg -ss 00:00:00 -i "%a" -to 01:00:00  -vcodec copy -acodec copy "%~na_cut.mp4


  


  Reduce framerate :

  


  for %a in ("*.mp4") do ffmpeg -i "%a" -filter:v fps=fps=30 "%~na_30fps.mp4


  


  It finally seems to work fine, but I am worried, because the original file has 2.6 GB, the converted and cut video file has 2.4 GB (which I find reasonable), but the video file with 30 fps has only 340 MB. It does not seem corect, that the files got so small. However, I used fprobe to determine the framerates and it shows that the fps should be as specified. Still, I find it puzzling that the video is now so small when only half the frames were dropped. Unfortunately, looking at the videos does not give hints if too many frames were dropped.

  


  I am grateful for any advice how to find the error or how to evaluate my result properly. Thank you for your help !