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• lavu : fix memory leaks by using a mutex instead of atomics

  14 novembre 2014, par wm4

  lavu : fix memory leaks by using a mutex instead of atomics
  The buffer pool has to atomically add and remove entries from the linked
  
  list of available buffers. This was done by removing the entire list
  
  with a CAS operation, working on it, and then setting it back again
  
  (using a retry-loop in case another thread was doing the same thing).
  This could effectively cause memory leaks : while a thread was working on
  
  the buffer list, other threads would allocate new buffers, increasing
  
  the pool’s total size. There was no real leak, but since these extra
  
  buffers were not needed, but not free’d either (except when the buffer
  
  pool was destroyed), this had the same effects as a real leak. For some
  
  reason, growth was exponential, and could easily kill the process due
  
  to OOM in real-world uses.
  Fix this by using a mutex to protect the list operations. The fancy
  
  way atomics remove the whole list to work on it is not needed anymore,
  
  which also avoids the situation which was causing the leak.
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DBH] libavutil/buffer.c
  • [DBH] libavutil/buffer_internal.h

• ffmpeg to encode MKV or MP4 with segmented Parts in one file

  28 juillet 2014, par Phil

  Is it Possible to create an MP4 or MKV file where the Video, Meta and Audio Data is segmented and placed alternated in a single File ? (By segmented I don’t mean different Video or Audio Tracks.)

  So that it looks like something like this :
  [meta][video][audio][meta][video][audio]…

  I searched for "segmenting", "clustering", and other buzz words. But the most searches ended up in an HTTP-Livestreaming where One File is segmented in single files.
  That Segmenting Technology is okay (so you can stream it). But I don’t want these segments in single Files, i want them to be in one single MKV or MP4 File.

  Maybe someone has any clue.

• FFMPEG Crop with side by side merge

  14 février 2016, par Alan

  I am trying to create a shell/ffmpeg script that can show multiple files after they have been processed using different filters in a side by side / tiled way. An example of desired output would be : https://www.youtube.com/watch?v=DoPuhMRYem4.

  In order to create the desired output I need to crop off the right half of video1 and the left half of video2 and then join them back with [video1+video2] side by side. I have played around with a bunch of different ways of joining them, this does OK :

  ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex "
  
  nullsrc=size=800x400 [background];
  
  [0:v] setpts=PTS-STARTPTS, scale=400x400 [left];
  
  [1:v] setpts=PTS-STARTPTS, scale=400x400 [right];
  
  [background][left]       overlay=shortest=1       [background+left];
  
  [background+left][right] overlay=shortest=1:x=400 [left+right]
  
  " -map '[left+right]' joined.mp4

  How can I modify this to detect the video width (they won’t always be the same width), divide the width in half and crop either the left or right sides off ?