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• ffmpeg filters order rotate scale with overlay

  13 décembre 2017, par Sebastián Márquez Lutfy

  I’m trying to render an image over a video. I use the following command after some research

  ffmpeg -y  -i "my_video.mp4" -i "my_image.jpg" -filter_complex "color=color=blue:size=711x400:rate=25[container];[0:v]scale=w=400:h=400,setpts=expr=PTS-STARTPTS[vidscaled];[container][vidscaled]overlay=eval=init:shortest=1:x=155:y=0[overlay0];[1:v]scale=w=123:h=123,rotate=a=323.7*PI/180:c=black@0:oh='roth(323.7*PI/180)':ow='rotw(323.7*PI/180)':bilinear=1[imgproc];[overlay0][imgproc]overlay=eval=init:x=18:y='237-abs(123*sin(323.7*PI/180))'[overlay1]" -map "[overlay1]" -map 0:a -strict -2 -preset ultrafast -g 120 output.mp4

  The problem with this approach is a low image’s quality since scaling is applied before rotate. So i tried to apply the rotation before scaling, (see next command)

  ffmpeg -y  -i "my_video.mp4" -i "my_image.jpg" -filter_complex "color=color=blue:size=711x400:rate=25[container];[0:v]scale=w=400:h=400,setpts=expr=PTS-STARTPTS[vidscaled];[container][vidscaled]overlay=eval=init:shortest=1:x=155:y=0[overlay0];[1:v]rotate=a=323.7*PI/180:c=black@0:oh='roth(323.7*PI/180)':ow='rotw(323.7*PI/180)':bilinear=1,scale=w=173:h=173[imgproc];[overlay0][imgproc]overlay=eval=init:x=18:y='237-abs(123*sin(323.7*PI/180))'[overlay1]" -map "[overlay1]" -map 0:a -strict -2 -preset ultrafast -g 120 output.mp4

  And the problem : c=black@0 is not working anymore, the bounding box around the rotated image is not transparent.

  Anyone please help this soul.

  pd : Using c=none doesn’t work too, got a green background

• avfilter/vf_showinfo : Fix erroneous results for mean and stdev with pixel bits >8

  6 janvier 2020, par Limin Wang

  avfilter/vf_showinfo : Fix erroneous results for mean and stdev with pixel bits >8
  Have tested with be and le pixel format on be and le system for >8bit.
  
  System :
  
  lmwang@ubuntu : /ffmpeg.git.mips$ grep HAVE_BIGENDIAN config.h
  
  ffmpeg.git git :(showinfo) ✗ grep HAVE_BIGENDIAN config.h
  Test result :
  
  1, yuv420p
  
  ./ffmpeg -f lavfi  -i color=black:duration=1:r=1:size=1280x720,format=yuv420p,showinfo
  
  Master :
  
  mean :[16 128 128] stdev :[0.0 0.0 0.0]
  
  After applied the patch :
  
   mean :[16 128 128] stdev :[0.0 0.0 0.0]
  2, yuv420p10le
  
  ./ffmpeg -f lavfi  -i color=black:duration=1:r=1:size=1280x720,format=yuv420p10le,showinfo
  
  Master :
  
  mean :[32 1 1] stdev :[32.0 1.0 1.0]
  
  After applied the patch :
  
  mean :[64 512 512] stdev :[0.0 0.0 0.0]
  3, yuv420p10be
  
  ./ffmpeg -f lavfi  -i color=black:duration=1:r=1:size=1280x720,format=yuv420p10be,showinfo
  
  Master :
  
  mean :[32 1 1] stdev :[32.0 1.0 1.0]
  
  After applied the patch :
  
  mean :[64 512 512] stdev :[0.0 0.0 0.0]
  Signed-off-by : Limin Wang <lance.lmwang@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavfilter/vf_showinfo.c

• How to get dimension and aspect ratio of input video and pass it as param to another input in the same command ?

  2 mars 2020, par theapache64

  I’ve a mp4 file. I want to create an input color feed with same dimension and sample aspect ratio. Currently, I use ffprobe to get dimension and sar as a separate command and pass it to ffmpeg command manually.

  ffmpeg -y
  -i input.mp4
  -i bgm.mp3
  -f lavfi -i color=c=black :s="1280"x"544":sar=1299/1280:d=3.0
  -filter_complex ...

  Is there any way to get dimension and sar of first input video to -f lavfi -i color.

  Something like

  -f lavfi -i color=c=black:s="widthOfFirstVideo"x"heightOfFirstVideo":sar=sarOfFirstVideo:d=3.0