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• ffmpeg : combining/ordering vidstab and crop filters

  30 juillet 2016, par ljwobker

  I have a workflow which essentially takes a raw video file, crops away portions of the frame that aren’t relevant, then performs a two-pass deshake filter using the vidstab filter. At the moment I’m running this as three distinct commands : one to do the crop, a second to do the vidstab "detect" pass, and a third to do the vidstab "transform" pass.

  My working script :

  # do the crop first and strip the audio
  
  nice -20 ffmpeg -hide_banner -ss $SEEK -i $INFILE -t $DURATION -preset veryfast -crf 12 -vf crop=0.60*in_w:in_h/9*8:0.22*in_w:0 -an -y $TEMP
  
  
  
  # now run the vidstab detection pass
  
  nice -20 ffmpeg -hide_banner -i $TEMP -vf vidstabdetect=stepsize=6:shakiness=10:accuracy=15:result=${INFILE}.trf -f null - 
  
  
  
  # now the vidstab transform, with unsharp and writing the overlay text
  
  nice -20 ffmpeg -hide_banner -i $TEMP -preset veryfast -crf 22 -vf \
  
  " \
  
  vidstabtransform=input=${INFILE}.trf:zoom=2:smoothing=60, 
  
  unsharp=5:5:0.8:3:3:0.4, 
  
  drawtext=fontfile=/Windows/Fonts/arialbd.ttf:text=$DIVE:enable='between(t,0,65)':fontcolor=black:fontsize=72:x=w*0.01:y=h*0.01,  
  
  null"\
  
    -y $OUTFILE

  What I can’t seem to figure out is how I can combine the first two filter passes into a single chain, which (at least in theory) would be a faster encode time, and at the very least would be simpler to maintain and would eliminate a pass of the encoder. What I tried to do was the second code block, which just builds a filterchain that combines the initial crop with the vidstab detection filter.

  # this is a combined filter for the crop and the vidstab detect
  
  nice -20 ffmpeg -hide_banner -ss $SEEK -i $INFILE -t $DURATION -preset veryfast -crf 12 -vf \
  
  " \
  
  crop=0.60*in_w:in_h/9*8:0.22*in_w:0,
  
  vidstabdetect=stepsize=6:shakiness=10:accuracy=15:result=${INFILE}.trf,
  
  null " \
  
  -an -r 30 -y $TEMP
  
  
  
  
  
  # now run the transcoding and the vidstab transform
  
  nice -20 ffmpeg -hide_banner -i $TEMP -preset veryfast -crf 22 -vf \
  
  " \
  
  
  
  vidstabtransform=input=${INFILE}.trf:zoom=2:smoothing=60, 
  
  unsharp=5:5:0.8:3:3:0.4, 
  
  drawtext=fontfile=/Windows/Fonts/arialbd.ttf:text=$DIVE:enable='between(t,0,65)':fontcolor=black:fontsize=72:x=w*0.01:y=h*0.01,  
  
  
  
  null"\
  
    -y $OUTFILE

  However, when I run this (and it runs) the final output video has most definitely NOT been effectively stabilized. The logs show that both the detect and the transform passes have been processed, it’s just that the output isn’t right.

• Anomalie #4213 (Nouveau) : Installation d’un spip en reprenant une base plus récente

  2 novembre 2018, par Maïeul Rouquette

  Petit couac qui m’est arrivé tout à l’heure (en local, heureusement).

  J’install un SPIP 3.1

  Au moment de la déclaration de base, je me trompe et au lieu de lui dire de créer une nouvelle base, je lui dit de reprendre une base existante. Or cette base était en SPIP 3.2

  SPIP reprend les données de la base MAIS change le spip_version_base.

  A mon avis le bon comportement devrait être "spip détecte qu’il y a un version base plus récent, il refuse l’installation"

• ffprobe Fastest way to read video packets

  12 novembre 2018, par secondplace

  I’ve been using ffprobe to read packets from video streams for analysis. However it’s painfully slow. A 30min 720p video takes roughly 8min to read.
  I’m using the following command at the moment :

  ffprobe.exe -i video.mp4 -show_entries packet=size,pts_time,flags,duration_time

  This gives me the following information for every packet :

  [PACKET]
  
  pts_time=1981.392000
  
  duration_time=0.032000
  
  size=1536
  
  flags=K_
  
  [/PACKET]

  I did read a fair bit in the documentation but it looks like this is just it or is there a way to make this faster ?

  Or would there be any alternative CLI tool to get the above information from a video faster ?