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• ffmpeg how to remove black borders when resizing an image

  3 juin 2021, par Mapg

  I am creating some thumbnails using FFmpeg and I see that some black borders are created when I resize them.

  


  I guess this is happening because the video source dimension doesn't match exactly the target dimension, so FFmpeg fills out the blank space with this black color.

  


  My question is ...

  


  Can I change this "black color" used by FFmpeg by default so I can match these extra borders added with the background of my application ?

  


  If this is not possible ...

  


  Can I convert these black borders to a transparent area so I can create a PNG to match my background which has a different color (a kind of light green)

  


  I have attached an example where you will see two black pixels height in the bottom zone of the picture.

  


  This is what I want to convert to transparent or being able to choose my own color.

  


  Any idea to solve this issue will be very helpful for me ?

  


  Thank you very much in advance !

  


  Mapg

  


  

  


• FFMPEG Padding 1 pixel

  21 juillet 2022, par Rittari771

  I've been playing around with the values in my padding code, but cannot seem to get the paddings to match exactly 1:1.
If we look really closely, it is 1 pixel off from
left side,
but right side seems fine (1:1 with the violet padding)

  


  I did get the left side to match, but then the right side is bad... i cant find a point between where both are equal.

  


  What can i do to match them ? Here is my code :

  


  ffmpeg -i video1.mp4 -filter_complex "pad=iw*1.1:0:ow*0.5:0:violet,scale=1080x1270" -y video1_padded.mp4
ffmpeg -i video2.mp4 -filter_complex "pad=iw*1.1:0:ow*0.5:0:cyan,scale=1080x650" -y video2_padded.mp4
ffmpeg -i video1_padded.mp4 -i video2_padded.mp4 -filter_complex "vstack=inputs=2" -y finalproduct.mp4


  


• problem compiling ffmpeg for iFrameExtractor

  11 septembre 2012, par Robin Rye

  I'm trying to compile the ffmpeg by using the make and build files in iFrameExtractor example. firstly i tried to follow the readme file on the github, which only says to run the ./build_universal in ffmpeg folder. it did not work

  i then tried to follow the info in INSTALL without success. i then tried doing the stuff in INSTALL followed by the ./build_universal which didn't work. All the *.a files that are imported to the project exists until the end of the build sequence. when the lipo commands in build_universal are run, which i guess concat the .a files for the different architectures(?). anyhow these leave the following errors :

  lipo: specifed architecture type (armv6) for file (armv6/libavcodec.a) does not match it's cputype (16777223) and cpusubtype (3) (should be cputype (12) and cpusubtype (6))
  
  lipo: specifed architecture type (armv6) for file (armv6/libavdevice.a) does not match it's cputype (16777223) and cpusubtype (3) (should be cputype (12) and cpusubtype (6))
  
  lipo: specifed architecture type (armv6) for file (armv6/libavformat.a) does not match it's cputype (16777223) and cpusubtype (3) (should be cputype (12) and cpusubtype (6))
  
  lipo: specifed architecture type (armv6) for file (armv6/libavutil.a) does not match it's cputype (16777223) and cpusubtype (3) (should be cputype (12) and cpusubtype (6))
  
  lipo: specifed architecture type (armv6) for file (armv6/libswscale.a) does not match it's cputype (16777223) and cpusubtype (3) (should be cputype (12) and cpusubtype (6))

  i can get the project to compile for simulator if i only use ./build_armv7 but if i run the universal the .a files are removed in the end. and only using doesn't work to build for iphone 4 .