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• How to modify this Windows script to do a match ?

  21 janvier 2016, par Andrei Clear

  ffmpeg can resize a video/image file .. first is input_file .. parameters .. output_file ..

  ffmpeg -i input.avi -vf scale=320:240 output.avi

  or

  ffmpeg -i 20140724_071746.mp4 -vf scale=640:-1 20140724_071746_LOW_640.mp4

  more info here : https://trac.ffmpeg.org/wiki/Scaling%20%28resizing%29%20with%20ffmpeg

  I want it to downscale all the videos on my microSD card to create space (I have originals backed-up)

  So I want it to go throw all the files in all the sub-directories overnight and resize all the files. Chances are that the script might stop or crash and I would need to run it again, or if I add new files I would want to run it again.

  So I would want it to skip processing all the files that have been processed AND their resized versions.

  In my case if a FILE_NAME.mp4 also has FILE_NAME_LOW_640.mp4 SKIP it
  AND
  if a FILE_NAME_LOW_640.mp4 has *640 SKIP it

  Here is my Windows batch script so far

  REM @echo off
  
  REM just save as "DOS"
  
  REM cd /d C:\s
  
  
  
  setlocal enabledelayedexpansion
  
  for %%j in (*.mp4) do (
  
  set filename=%%~nj
  
  echo %%j
  
  
  
  ffmpeg -i %%j -vf scale=640:-1 %%j_LOW_640.mp4
  
  
  
  REM but now I want to add the two checks to skip files that have been resized .. or if they are the resized version 
  
  
  
  REM if not "!filename!"=="%%j_LOW_640.mp4" AND IF FILE !COINTAIN *640* THEN ffmpeg -i %%j -vf scale=640:-1 %%j_LOW_640.mp4
  
  
  
  )
  
  
  
  pause
  
  REM AND I would also want it to process all the sub-directories  

  In other words my questions for help are :

  1. How can I do a check for a string if it contains a string match ?

  2. How can I have my script also process all the subdirectories ?

• Trailing backslash of variable in ffmpeg command

  20 novembre 2022, par paulwen

  Issue detail :

  


  I use ffmpeg to add a text watermark and define the position using a function,
x=if(eq(mod(t\,4)\,0)\,rand(0\,500\)\,x), random position of x
I wanna to know why we have to use the trailing backslash ?
Why can't we use x=if(eq(mod(t,4),0),rand(0,500),x) ?

  


  ERROR

  


  ...
[AVFilterGraph @ 0000029e7b56e7c0] No such filter: '100),x):y'
Error reinitializing filters!
...



  


  Here's the command

  


  ffmpeg -i sample.mp4 -vf drawtext="text='Text Here':x=if(eq(mod(t\,4)\,0)\,rand(0\,100\)\,x):y=100" randomWatermark.mp4.

  


  I tried to remove any backSlash, but all failed.
even just remove backslash beside 0,as
x=if(eq(mod(t\,4)\,0)\,rand(0,500\,x)
I google a lot, the answers almost say it's a special character, use to escaping characters or used for another new line.

  


• FFMPEG : what is the limit of parameter using for text to video ?

  11 juillet 2017, par Bunker Boy

  i am using ffmpeg for text to video conversion and everything working fine just only can not decide how much fontsize can accepted there and height & width limit for video as well as how many characters can allow ?
  the command i am using

  ffmpeg -f lavfi -i color=c=0x000000:s=1600x1600 -vf
  "drawtext=fontfile=PATHOFFONTS/DejaVuSans.ttf:fontsize=96:fontcolor=0xffffff:y=(h-line_h)/2:x=-(4*n)+W:text=’text
  text text long text long text long text’" -r 24 -t 1140
  PATHTOSAVE/video.mp4

  here text moving from right to left.

  -t 1140 // is the time i have calculated separately

  s=1600x1600 then video mime type got corrupted and video is not working well.

  can anybody let me know what is the minimum and maximum range i can pass for fontsize, height, width and text ?