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• Setting transfer characteristics for overlaying multiple videos

  12 décembre 2023, par Prakkash

  I just wanna know whether I can set unique values of transfer characteristics/gamma for each videos while overlaying it on top of a single video.

  


  For example :-

  


  FFmpeg command : ffmpeg -f lavfi -i color=c=#ffffff:s=1920x1080:d=43 -i abc.mp4 -i def.mp4 -filter_complex "[1:v]setpts=PTS+0/TB[top1] ; [2:v]setpts=PTS+12.9/TB[top2] ;[0:v][top1]overlay=-0.75:0:enable='between(t,0,12.9)'[outv1] ; [outv1][top2]overlay=-66:0:enable='between(t,12.9,42.9)'[outv2] ;" -map "[outv2]" -c:v libx264 -preset ultrafast -c:a copy -strict experimental output.mp4 -y

  


  In this command, abc.mp4 video has a transfer characteristics value of 1 and def.mp4 has the transfer characteristics value of 7. I'm trying to overlay both videos on top of a white background. By default, the white background has transfer characteristics value as 1. So def.mp4 video's color gets dull. How can i handle this ?

  


• ffmpeg perspective filter animation error

  17 mars 2021, par eeun

  I'm trying to create a pseudo-3d pan effect in ffmpeg using the perspective filter.

  


  Here is a sample for the starting point...

  


  ffmpeg -y -filter-complex "color=black:s=1600x900,trim=0:5,drawgrid=width=100:height=100:thickness=2:color=white,perspective=x0=200:y0=200:x1=1600:y1=0:x2=200:y2=700:x3=1600:y3=900[skew]" -an -map [skew] "skew-start.mp4"


  


  And here is a sample for the end point...

  


  ffmpeg -y -filter-complex "color=black:s=1600x900,trim=0:5,drawgrid=width=100:height=100:thickness=2:color=white,perspective=x0=0:y0=0:x1=1600:y1=0:x2=0:y2=900:x3=1600:y3=900[skew]" -an -map [skew] "skew-end.mp4"


  


  So far so good. Adding the animation would give this...

  


  ffmpeg -y -filter-complex "color=black:s=1600x900,trim=0:5,drawgrid=width=100:height=100:thickness=2:color=white,perspective=eval=frame:x0='200-(200*t/5)':y0='200-(200*t/5)':x1=1600:y1=0:x2='200-(200*t/5)':y2='700+(200*t/5)':x3=1600:y3=900[skew]" -an -map [skew] skew.mp4


  


  This is where the problem occurs. I get an error saying [Eval @ 000000f36ebfebf0] Undefined constant or missing '(' in 't/5)' Error while filtering: Invalid argument

  


  The perspective docs say it should work with an eval=frame option. Anyone got any ideas ? Does this look like a bug in ffmpeg ? I'm using the latest version, 4.3.2.

  


• Does exists other way of indenting ffmpeg batch script ?

  22 mars 2021, par Toni Cambronero Garcia

  How can I indent code in a Batch script other than using temporal variables %= =% ?
This is the only code that works for me with indentation.

  


  ::2020-12-31 10:43:40
@ECHO OFF
::SET VIDEO="E:\Vídeos\test.mp4"
SET VIDEO=%1
SET /P TITULO=Introduzca el título del vídeo: 
ffmpeg ^
    -y ^
    -loglevel verbose ^
    -i %VIDEO% ^
    -vf ^
          scale=^
%=          =%width=-2:^
%=          =%height=360,^
%=      =%drawtext=^
%=          =%fontfile='C\:/Windows/Fonts/impact.ttf':^
%=          =%text=%TITULO%:^
%=          =%fontcolor=white:^
%=          =%borderw=1:^
%=          =%fontsize=18:^
%=          =%alpha=0.99:^
%=          =%x=(w-tw)/2:^
%=          =%y=th/4:^
%=          =%expansion=none,^
%=      =%drawtext=^
%=          =%fontfile='C\:/Windows/Fonts/arial.ttf':^
%=          =%text='WATERMARK':^
%=          =%fontcolor=white:^
%=          =%borderw=1:^
%=          =%fontsize=18:^
%=          =%alpha=0.60:^
%=          =%x=w-tw-10:^
%=          =%y=h-th-10:^
%=          =%expansion=none^
    -map 0:v ^
    -map 0:a? ^
    -c:v h264 ^
    -crf 30 ^
    -c:a aac ^
    -q:a 1 ^
    -ac 1 ^
    %VIDEO:~0,-5%_WATERMARK.mp4


  


  If I try to use spaces or tabs in the "-vf" section ffmpeg interprets them as the end of the filter and the start of the output file argument .