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• avfilter/vf_dedot : Fix leak of AVFrame if making it writable fails

  9 février 2020, par Andreas Rheinhardt

  avfilter/vf_dedot : Fix leak of AVFrame if making it writable fails
  Even in this scenario, the frame still contains references to data that
  
  won't be freed if the frame isn't unreferenced. And the AVFrame itself
  
  will leak, too.
  Fixes Coverity issue #1441422.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavfilter/vf_dedot.c

• FATE : Add test for libavfilter/scale2ref

  4 juin 2017, par Kevin Mark

  FATE : Add test for libavfilter/scale2ref
  This new FATE test for the scale2ref filter makes use of the recently
  
  added scale2ref-specific variables to maintain the aspect ratio of a
  
  test input.
  Filtergraph explanation :
  
  [main] has an AR of 4:3. [ref] has an AR of 16:9.
  
  640 / 4 = 160. So the new width for [main] is 160.
  
  160 / ((320 / 240) * (1 / 1)) = 160 / (4 / 3) = 120. So the new
  
  height for [main] is 120.
  
  160 / 120 = 4 / 3 so [main]'s aspect ratio has been maintained while
  
  using [ref]'s width as a reference point.
  [ref] is nullsink'd since it is left unchanged by scale2ref (and so
  
  shouldn't need to be tested).
  If we were to use "iw/4 :-1" in place of "iw/4:ow/mdar" :
  
  640 / 4 = 160. So the new width for [main] would be 160.
  
  360 / 4 = 90. So the new height for [main] would be 90.
  
  160 / 90 = 16 / 9 so [main] now has the same aspect ratio as [ref]
  
  which is probably what you do not want.
  This is currently the only test for scale2ref.
  Signed-off-by : Kevin Mark <kmark937@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] tests/fate/filter-video.mak
  • [DH] tests/filtergraphs/scale2ref_keep_aspect
  • [DH] tests/ref/fate/filter-scale2ref_keep_aspect

• extract audio channels using ffmpeg-python wrapper

  21 mars 2023, par Azazel

  I read previous posts about this, but none seems to work/cover this specific scenario

  


  I am using ffmpeg-python, and I am trying to extract the audio channels from a file which I dont know how many channels it has.

  


  I've been looking at pan and channelsplit methods from ffmpeg doc page, and tried to implemente with the wrapper, but get syntax error or invalid argument or No option name near... Error parsing a filter description arround [s0] error from ffmpeg.

  


  I have also tried using map='0:a:0 on the output method but it doesnt extract the channels.

  


  Since I dont know how many streams nor channels the audio will have, my idea was to split them all using ffmpeg.input("input.mp3").filter('channelsplit'), but first : the default for this is "stereo", and I dont know if my audio will have stereo or mono. Or 5.1, etc (I know I can check with ffprobe, but can an audio file have a mix of streams ?)

  


  Anyway, I tried with pan filter too, as ffmpeg.input("input.mp3").filter('pan', 'pan=1|c0=c0')