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• ffmpeg resize down larger video to fit desired size and add padding

  5 février 2017, par misterjinx

  I’m trying to resize a larger video to fit an area that I have. In order to achieve this I calculate first the dimensions of the resized video so That it fits my area, and then I try to add padding to this video so that the final result will have the desired dimension, keeping the aspect ratio as well.

  So let’s say that I have the original video dimensions of 1280x720 and to fit my area of 405x320 I need first to resize the video to 405x227. I do that. Everything is fine at this point. I do some math and I find out that I have to add 46 pixels of padding at the top and the bottom.

  So the padding parameter of the command for that would be -vf "pad=405:320:0:46:black". But each time I run the command I get an error like Input area 0:46:405:273 not within the padded area 0:0:404:226.

  The only docs for padding that I found is this http://ffmpeg.org/libavfilter.html#pad.

  I don’t know what I’m doing wrong. Anyone had this problem before ? Do you have any suggestions ?

• Use FFMPEG to create video from jpeg, and index using vlc

  16 novembre 2011, par Greg

  OpenSuse 11.4
  FFMEG 0.8.5

  I'm using FFMPEG to create a 5 minute mpeg from about 2100 individual jpegs (7fps). I've been using the following command (OpenSuse 11.4)
  /usr/bin/ffmpeg -y -r 7.01 -i %03d-capture.jpg -s 800x600 -r 25 Event-3692-r1-s1-3.mpg

  Now I Try to open the file (In windows XP with VLC 1.1.11 Player).
  Media->AdvancedFileOpen
  *I select "Show more options" and set StartTime to 5s. I expect that the video should start 5 seconds in, but instead it starts at a seemingling random (although consistent) time of 30 seconds in.

  I also tried changing ffmpeg command to :
  /usr/bin/ffmpeg -sameq -y -r 7.01 -i %03d-capture.jpg -s 800x600 -r 25 Event-3692-r1-s1-3.mpg
  *This result in about a constant 2x offset (5sec => 10sec) (10s => 20s) etc. But filesize is also about 6x larger, which is a strain on my storage.

  I also tried
  /usr/bin/ffmpeg -y -r 7.01 -i %03d-capture.jpg -s 800x600 -r 25 -f mpegts Event-3692-r1-s1-3.mpg
  *This result in vlc not indexing at all into my video. Also not desired. Anybody have any clues what is going on here. It is very important for me to be able to use this VLC feature and have it work correctly.

  Thanks in advance

• HTML5 Video FFMPEG Shell Script

  18 novembre 2011, par Schermy

  I wrote this quick and dirty shell script to run ffmpeg over a bunch of files to generate webm/ogg/h.264 videos for a HTML5 site.

  #!/bin/bash
  
  
  
  ext=$1
  
  enc=$2
  
  
  
  #!/bin/bash
  
  for file in *.$ext; do
  
          while pidof /usr/local/bin/ffmpeg; do sleep 10; done >/dev/null
  
  
  
          ffmpeg -i "$file" -s 1280x720 -b 500k  "${file/%$ext/$enc}"   
  
  done

  It works great for my purposes but I've noticed that each video now takes a lot longe to convert and ffmpeg is not taking advantage of my multi-core setup.

  I would like to improve this script when I have some time and make it available for use by others but I'd like to solve this issue first.

  Thanks in advance for all of your help.

  P.S. This is setup to use the ffmpeg installation from brew on the Mac (and yes I would like to make this script more platform agnostic later on).