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• FFMPEG crop boundaries animation

  28 septembre 2021, par VlFedotov

  I'm looking for a way to make crop filter params depends on current time.

  


  Now I have 2 videos - white and aqua squares in one split output video, and this code works fine :

  


  ffmpeg -i out/i1.mp4 -i out/i2.mp4 -filter_complex "[0:v]crop=iw/2:ih:0:0[left];[1:v]crop=iw/2:ih:ow:0[right];[left][right]hstack" out/generated.mp4


  


  My question is - how to make the border between two videos floating, animated ? For example from left side of output vide to the right ?

  


  I already tried to use t param, e.g. like this :

  


  ffmpeg -i out/i1.mp4 -i out/i2.mp4 -filter_complex "[0:v]crop=iw/2+t:ih:0:0[left];[1:v]crop=iw/2-t:ih:ow:0[right];[left][right]hstack" out/generated.mp4


  


  But it throws an error :

  


  [Parsed_crop_0 @ 0x7fa46060eec0] Error when evaluating the expression 'iw/2+t'

[Parsed_crop_0 @ 0x7fa46060eec0] Failed to configure input pad on Parsed_crop_0

Error reinitializing filters!

Failed to inject frame into filter network: Invalid argument

Error while processing the decoded data for stream #1:0


  


  Can anybody help me to solve this ? Or explain - why it isn't possible ?

  


• bash : receive single frames from ffmpeg pipe

  30 août 2014, par manu

  I’m trying to achieve single-frame handling in a pipe where the the j2c encoder "kdu_compress" (Kakadu) only accepts single files. To save harddrive space. I didn’t manage to pipe frames directly, so I’m trying to handle them via a bash script, by creating each picture, process it, and overwrite it with the next.

  Here is my approach. Thanks for your advice, I really want to climb this mountain, though I’m a bit fresh here thanks.

  ---

  Is it possible to pipe an ffmpeg output to a bash script and save the individual frame,
  do further commands with the file before the next frame is handled ?

  Best result so far is, that ALL frames are added into the intermediate file, without recognizing the end of a frame.

  I used this ffmpeg setting to pipe, example with .ppm :

  ffmpeg -y  -i "/path/to/source.mov" -an -c:v ppm -updatefirst 1 -f image2 - \
  
   | /path/to/receiver.sh

  and this script as a receiver.sh

  #!/bin/bash  
  
  
  
  while read a; 
  
  do 
  
      cat /dev/null > "/path/to/tempfile.ppm"; #to empty the file first
  
      cat $a >> "/path/to/tempfile.ppm";        #to fill one picture
  
  
  
      kdu_compress -i /path/to/tempfile.ppm -otherparams   #to process this intermediate
  
  
  
  done
  
  exit;

  Thank you very much.

• avcodec/libx265 : Don't use AVBPrint unnecessarily

  22 mars 2024, par Andreas Rheinhardt

  avcodec/libx265 : Don't use AVBPrint unnecessarily
  This code uses the AVBPrint API for exactly one av_bprintf()
  
  in a scenario in which a good upper bound for the needed
  
  size of the buffer is available (with said upper bound being
  
  much smaller than sizeof(AVBPrint)). So one can simply use
  
  snprintf() instead. This also avoids the (always-false due to
  
  the current size of the internal AVBPrint buffer) check for
  
  whether the AVBPrint is complete.
  Furthermore, the old code used AV_BPRINT_SIZE_AUTOMATIC
  
  which implies that the AVBPrint buffer will never be
  
  (re)allocated and yet it used av_bprint_finalize().
  
  This has of course also been removed.
  Reviewed-by : Jan Ekström <jeebjp@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/libx265.c