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• libavformat/mov : Accept known codepoints in ’colr’

  17 août 2016, par Steven Robertson

  libavformat/mov : Accept known codepoints in ’colr’
  This change relaxes the whitelist on reading color metadata in MOV/BMFF
  
  containers. The whitelist on writing values is still in place.
  As a consequence it also fixes an apparent bug in reading ’nclc’ values.
  
  The ’nclc’ spec [1] is in harmony with ISO 23001-8 for the values it
  
  lists, but the code getting removed was remapping 5->6 and 6->7 for
  
  primaries, which is incorrect, and was remapping 6->5 for color matrix
  
  ("colorspace" in the code), which is equivalent but an unnecessary
  
  inconsistency. This logic error doesn’t appear in movenc.
  Removing the whitelist allows proper conversion when the source codec
  
  relies on the container for proper signaling of newer codepoints, such
  
  as DNxHR and VP9. If converting to a codec or container that has updated
  
  its spec to include the new codepoints, the metadata will be preserved.
  
  If going back to MOV/BMFF, the output whitelist will still kick in, so
  
  this won’t result in out-of-spec files being created.
  [1] https://developer.apple.com/library/mac/technotes/tn2162/_index.html
  Signed-off-by : Steven Robertson <steven@strobe.cc>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/mov.c

• Multiply the video with a scalar with FFMPEG

  16 novembre 2020, par Terpsiphone

  I have to adjust a video which was too dark. In openCV, I simply used Img.Mul() to multiply each of the RGB band with a same scalar and got good result.

  


  Could one do the equivalent operation with FFMPEG ? I tried eq with contrast and brightness, but it was not quite the same thing.

  


  Edit : thanks to a clue in @VC.One's answer below I was able to emulate Img.Mul() with :

  


  ffmpeg -i input.file -vf colorlevels=rimax=0.5:gimax=0.5:bimax=0.5 -c:a copy output.file


  


• change max Buffer Length in MPEG-dash format

  17 novembre 2020, par ADL

  I'm trying to change the max buffer length on my video streaming in clappr video player.
I know that in HLS format the way to do it is like this :

  


  player = new Clappr.Player({
      playback: {
        hlsjsConfig: {
         maxMaxBufferLength: 30
      }}})


  


  And it's realy working for HLS videos,
I'm looking for equivalent way to do it with MPEG-dash foramt