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• avfilter/f_ebur128 : add all sample rates support

  4 mars 2021, par Paul B Mahol

  avfilter/f_ebur128 : add all sample rates support
  The magic constants come from the unofficial "ITU-R BS.1770-1 filter
  
  specifications"¹ by Raiden (libebur128) which relies on "Parameter
  
  Quantization in Direct-Form Recursive Audio Filters"² by Brian
  
  Neunaber.
  The constants seem to include a quantization bias, for example :
  
   Vb is supposed to be exactly √Vh in a high shelf filter
  
   the Pre-filter Gain should likely be 4dB
  
   Pre Q and RLB Q are respectively very close to √½ and ½
  Those are not adjusted to prevent the values from drifting away from
  
  the official specifications.
  An alternative to this approach would be to requantize on the fly as
  
  proposed by pbelkner³, where the 48kHz code path would use the exact
  
  specifications constants while derivating constants for other
  
  frequencies.
  [1] : https://www.scribd.com/document/49991813/ITU-R-BS-1770-1-filters
  
  [2] : https://www.scribd.com/document/6531763/Direct-Form-Filter-Parameter-Quantization
  
  [3] : https://hydrogenaud.io/index.php?topic=86116.msg740092#msg740092
  

  • [DH] libavfilter/f_ebur128.c

• Anomalie #3790 (Fermé) : Recherche esapce privé et pagination

  13 août 2016, par Anonyme

  Appliqué par commit r23122.

• Révision 19533 : Report de r19502

  5 juin 2012, par cedric -

  forcer le reload si redirection demandee par form ajax : si url differente c’est ignoré, mais si seul l’ancre change, ça force la mise a jour de la pag et r19525 Ne forcer un reload que si c’est un changement d’ancre simple (sinon le reload se declenche parfois plus vite que le redirect et ça (...)