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• ffv1 : Explicitly name the coder type

  15 novembre 2015, par Vittorio Giovara

  ffv1 : Explicitly name the coder type
  FFv1 uses two types of coders, golomb and range with two different
  
  tables. This is exposed this in a rather convoluted way, for example
  
  mentioning to set coder type 1 while initializing the variable ’ac’ to 2,
  
  because encoder does not use range coder with default table.
  Appropriate internal coder type values have been added and used in any
  
  check rather than using raw numbers.
  Initialization of avctx.coder_type in ffv1dec is removed because this
  
  field is encoder only. An unneeded validation check in the encoder
  
  is dropped too.
  Signed-off-by : Vittorio Giovara <vittorio.giovara@gmail.com>
  

  • [DBH] libavcodec/ffv1.c
  • [DBH] libavcodec/ffv1.h
  • [DBH] libavcodec/ffv1dec.c
  • [DBH] libavcodec/ffv1enc.c

• Difference in number of channels returned by mediainfo and ffprob

  16 mars 2021, par Hai Tran

  I was examining an audio file and noticed that the numbers of channels returned by mediainfo and ffprobe were different.

  


  The mediainfo command :

  


  mediainfo audio.mp4


  


  The ffprobe command (see the channels value) :

  


  ffprobe -i audio.mp4 -show_streams


  


  Does anyone know what's happening ?
Here is the audio file for your own test.

  


• avutil/common : add av_rint64_clip

  1er novembre 2015, par Ganesh Ajjanagadde

  avutil/common : add av_rint64_clip
  The rationale for this function is reflected in the documentation for
  
  it, and is copied here :
  Clip a double value into the long long amin-amax range.
  
  This function is needed because conversion of floating point to integers when
  
  it does not fit in the integer’s representation does not necessarily saturate
  
  correctly (usually converted to a cvttsd2si on x86) which saturates numbers
  
  > INT64_MAX to INT64_MIN. The standard marks such conversions as undefined
  
  behavior, allowing this sort of mathematically bogus conversions. This provides
  
  a safe alternative that is slower obviously but assures safety and better
  
  mathematical behavior.
  
  API :
  
  @param a value to clip
  
  @param amin minimum value of the clip range
  
  @param amax maximum value of the clip range
  
  @return clipped value
  Note that a priori if one can guarantee from the calling side that the
  
  double is in range, it is safe to simply do an explicit/implicit cast,
  
  and that will be far faster. However, otherwise this function should be
  
  used.
  avutil minor version is bumped.
  Reviewed-by : Ronald S. Bultje <rsbultje@gmail.com>
  
  Signed-off-by : Ganesh Ajjanagadde <gajjanagadde@gmail.com>
  

  • [DH] libavutil/common.h
  • [DH] libavutil/version.h