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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 ?

• FFMPEG - build ubuntu 32 bit - missing shared library : libspeex

  29 avril 2013, par Benoit Brayer

  I am currently doing a cross platform software calling ffmpeg in c++ and I need a ffmpeg build working on both ubuntu 32bits and 64bits for the installer.
  I also need this ffmpeg build to include librtmp, libh264, x11-grab, alsa, and mp3.

  I tried to compile ffmpeg on a 32bits virtual box to have a ffmpeg build working on ubuntu 32 bits and 62 bits.

  I used this guide to build ffmpeg :
  https://ffmpeg.org/trac/ffmpeg/wiki/UbuntuCompilationGuide

  After compiling all the libs and ffmpeg himself, after installation using the deb files, ffmpeg is working perfectly on the 32bits virtualbox with all of my required components but not on my 62bits ubuntu.

  When executing ffmpeg on ubuntu 64bits i got a message saying : impossible find the shared library libspeex.

  Do you have any idea why I have this problem only on linux 64bits with the save deb files ?
  Do you know a website where i could find an ffmpeg 32bits build with all the components I need (static if possible) ?
  I tried this website http://ffmpeg.gusari.org/static/ but the build is not including alsa...

  I have a build for windows working perfectly, I downloaded the 32 bits static build on this website : zeranoe builds website for windows.

  Thanks in advance for any answer.
  Regards.

  Benoit Brayer

• Save Slow motion video with ffmpeg on android devices

  25 mars 2017, par nkalra0123

  I want to save videos in slow motion through my android app.I tried to convert videos into slow motion by changing frame rate.

  I used the following commands,first command is dumping 30 frames per second from videos to a temp directory, and then second command is using these images to create a video with reduced or faster frame rate and then i am deleting all the images from temp directory.

  ffmpeg -i input_file.mp4 -r 30/1 img%03d.png
  
  
  
  ffmpeg -framerate 15/1 -i img%03d.png -r 30 -pix_fmt yuv420p out4.mp4

  But this is a very slow operation. It is taking like forever even for small videos.

  I even tried to change PTS(presentation time stamp) of videos, but it is not working properly on android phones
  using this command :

  ffmpeg -i input.mkv -filter:v "setpts=2.0*PTS" output.mkv

  as suggested here :
  https://trac.ffmpeg.org/wiki/How%20to%20speed%20up%20/%20slow%20down%20a%20video

  Can anybody suggest me how can i make it fast. Is it necessary to save frames to a temp directory, can i pass the output of ffmpeg process to another ffmpeg process executing concurrently through some method.

  Is there any other ffmpeg command to save the videos in slow motion ?