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• Revision 55121506e87fc6bf8ed0e298cad65d98f99f096d : Report en 2.2 de [16521]. Le calcul du nom de login à partir du mail ...

  28 octobre 2010, par Committo,Ergo:sum — Log

  Report en 2.2 de [16521]. Le calcul du nom de login à partir du mail n’avait jamais marché. Six ans après [3824] on s’en aperçoit. git-svn-id : svn ://trac.rezo.net/spip/branches/spip-2.2@16522 caf5f3e8-d4fe-0310-bb3e-c32d5e47d55d

• FFMPEG - Video micro stutters at merge point after cutting a 1 second segment, adding fade effect to it and concatenating it back

  9 septembre 2023, par john

  So i've been using Losslesscut (it uses FFMPEG) to edit videos, but because this program doesn't have any option for fade in/out effects, I came up with this method where i cut a 1 second segment before and after every cut I would do to the video, and then I run a batch FFMPEG command that adds fade in/out effect too all 1 second segments, and then I run another batch command to concat all parts.

  


  What all this does is it keeps 99% of the video lossless, only reencoding the 1 second segments for the fade effect.

  


  The problem is each 1 second segment that gets merged back creates a micro stuttering at the merge point. And because it's a lot of segments, the video ends up with lots of micro stuttering throughout. It's nothing crazy but definetly noticeable.

  


  I believe the issue is probably caused by imprecision on the cuts made on Losslesscut (I mean, it's just using FFMPEG keyframe cut, my videos have 1 keyframe per second). The 1 second segments end up with 61, 62, or even 63 frames (the video is 60fps). Although if, for testing purposes, I merge the 1 segment without reencoding it, there is no stutter.

  


  I think the reencode further messes with the time / frames of the video, might be adding an additional frame or extra miliseconds, even tho the fade duration is 1 second.

  


  Wondering if anyone can think of something that would make the merging smooth and get rid of the stutter ?

  


  These are the fade effect and the concat command I'm using :

  


  ffmpeg -i "input" -vf "fade=t=in:st=0:d=1" -c:v h264_nvenc -profile:v high -rc constqp -qp 14 -c:a copy -video_track_timescale 90000 "output"

ffmpeg -f concat -safe 0 -i "FILELIST.TXT" -c copy "output"


  


  I also tested doing the cutting via FFMPEG directly, and still got the after merging the fade clips.

  


  Guessing it won't be possible to fix this, since it's merging a reencoded clip with a lossless one. Who knows tho.

  


  Thanks in advance.

  


• Add first micro-benchmark

  31 août 2015, par Erik de Castro Lopo

  Add first micro-benchmark
  

  • [DH] .gitignore
  • [DH] Makefile.am
  • [DH] configure.ac
  • [DH] microbench/Makefile.am
  • [DH] microbench/benchmark_residual.c
  • [DH] microbench/util.c
  • [DH] microbench/util.h