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• aacenc_pred : rework the way prediction is done

  29 août 2015, par Rostislav Pehlivanov

  aacenc_pred : rework the way prediction is done
  This commit completely alters the algorithm of prediction.
  
  The original commit which introduced prediction was completely
  
  incorrect to even remotely care about what the actual coefficients
  
  contain or whether any options were enabled. Not my actual fault.
  This commit treats prediction the way the decoder does and expects
  
  to do : like lossy encryption. Everything related to prediction now
  
  happens at the very end but just before quantization and encoding
  
  of coefficients. On the decoder side, prediction happens before
  
  anything has had a chance to even access the coefficients.
  Also the original implementation had problems because it actually
  
  touched the band_type of special bands which already had their
  
  scalefactor indices marked and it’s a wonder the asserion wasn’t
  
  triggered when transmitting those.
  Overall, this now drastically increases audio quality and you should
  
  think about enabling it if you don’t plan on playing anything encoded
  
  on really old low power ultra-embedded devices since they might not
  
  support decoding of prediction or AAC-Main. Though the specifications
  
  were written ages ago and as times change so do the FLOPS.
  Signed-off-by : Rostislav Pehlivanov <atomnuker@gmail.com>
  

  • [DH] libavcodec/aac.h
  • [DH] libavcodec/aaccoder.c
  • [DH] libavcodec/aacenc.c
  • [DH] libavcodec/aacenc.h
  • [DH] libavcodec/aacenc_pred.c
  • [DH] libavcodec/aacenc_pred.h

• Revision c3378771b3 : third_party/libwebm : pull from upstream Pulling libwebm from upstream Changes

  2 mai 2014, par Vignesh Venkatasubramanian

  Changed Paths :
   Modify /third_party/libwebm/README.libvpx

  
   Modify /third_party/libwebm/mkvmuxer.cpp

  
   Modify /third_party/libwebm/mkvmuxer.hpp

  
   Modify /third_party/libwebm/mkvmuxertypes.hpp

  
   Modify /third_party/libwebm/mkvmuxerutil.cpp

  
   Modify /third_party/libwebm/mkvmuxerutil.hpp

  
   Modify /third_party/libwebm/mkvparser.cpp

  
   Modify /third_party/libwebm/mkvparser.hpp

  
   Modify /third_party/libwebm/mkvreader.cpp

  
   Modify /third_party/libwebm/mkvreader.hpp

  
   Modify /third_party/libwebm/mkvwriter.cpp

  
   Modify /third_party/libwebm/mkvwriter.hpp

  
   Modify /third_party/libwebm/webmids.hpp

  
  
  third_party/libwebm : pull from upstream

  Pulling libwebm from upstream

  Changes from upstream :
  249629d make Mkv(Reader|Writer)(FILE*) explicit
  7f3cda4 mkvparser : fix a bunch of windows warnings
  5c06178 Merge "clang-format on mkvparser.[ch]pp"
  4df111e clang-format on mkvparser.[ch]pp
  7b24501 clang-format re-run.
  c6767b9 Change AlignTrailingComments to false in .clang-format
  9097a06 Merge "muxer : Reject file if TrackType is never specified"
  eddf974 Merge "clang-format on mkvmuxertypes.hpp and webmids.hpp"
  def325c muxer : Reject file if TrackType is never specified
  41f869c Merge "clang-format on webvttparser.(cc|h)"
  fd0be37 clang-format on webvttparser.(cc|h)
  207d8a1 Merge "clang-format on mkvmuxerutil.[ch]pp"
  02429eb Merge "clang-format on mkvwriter.[ch]pp"
  0cf7b1b Merge "clang-format on mkvreader.[ch]pp"
  2e80fed Merge "clang-format on sample.cpp"
  3402e12 Merge "clang-format on sample_muxer.cpp"
  1a685db Merge "clang-format on sample_muxer_metadata.(cc|h)"
  6634c7f Merge "clang-format on vttreader.cc"
  7566004 Merge "clang-format on vttdemux.cc"
  9915b84 clang-format on mkvreader.[ch]pp
  7437254 clang-format on mkvmuxertypes.hpp and webmids.hpp
  0d5a98c clang-format on sample_muxer.cpp
  e3485c9 clang-format on vttdemux.cc
  46cc823 clang-format on dumpvtt.cc
  5218bd2 clang-format on vttreader.cc
  1a0130d clang-format on sample_muxer_metadata.(cc|h)
  867f189 clang-format on sample.cpp
  4c7bec5 clang-format on mkvwriter.[ch]pp
  9ead078 clang-format on mkvmuxerutil.[ch]pp
  fb6b6e6 clang-format on mkvmuxer.[ch]pp
  ce77592 Update .clang-format to allow short functions in one line
  0a24fe4 Merge "Add support for DateUTC and DefaultDuration in MKV Muxer."
  11d5b66 Merge "Add .clang-format"
  a1a3b14 Add .clang-format
  0fcec38 Add support for DateUTC and DefaultDuration in MKV Muxer.

  Change-Id : Ia0ed161ffc3d63c2eba8ed145707ffe543617976

• avformat/matroskadec : Allow to count the number of element occurences

  16 février 2021, par Andreas Rheinhardt

  avformat/matroskadec : Allow to count the number of element occurences
  Up until now, the generic EBML reader used by the Matroska demuxer did
  
  not have the capability to record whether an element was actually
  
  present or not ; instead, in cases where it mattered one typically added
  
  an invalid default value and checked whether the value is valid (in
  
  which case it is guaranteed to be present). This worked pretty well so
  
  far, yet the EBML specifications have evolved : It is now legal to use
  
  zero-length elements for floats, ints, uints and strings (both ASCII and
  
  UTF-8) ; the value of these elements is the default value of the element
  
  (if it has one) or zero for scalar types and an empty string for
  
  strings. Furthermore, having a default value does no longer imply that
  
  the element may be presumed to be present (with its default value) if it
  
  is absent ; this is only true if the element is mandatory, too.
  These rules are designed to allow size savings as follows : Consider the
  
  newly added FlagOriginal : It being zero means the track is not in its
  
  original language, it being one means it is. For backward compatibility
  
  reasons, neither of the two values may be inferred automatically in the
  
  absence of the element. But one can still save a byte when one wants to
  
  write the element with a value of zero, as one can write the integer with
  
  a length of zero : 0x55AE 80 instead of 0x55AE 81 00. In the former case,
  
  a parser has to infer the value of the element to be zero (which is the
  
  element's default value).
  When encountering an element with length zero, our parser always infers
  
  a value of zero (or an empty string) ; this is wrong for values with
  
  a different default value. It needs to infer the default value (or zero
  
  in its absence) and this precludes using an invalid default value for
  
  elements like FlagOriginal. Ergo one needs to be able to record whether
  
  an element is present or not by other means. This patch allows to use a
  
  simple counter for this. While just at it, some invalid and unnecessary
  
  default values have been removed (mastering metadata elements used
  
  default values of -1.0, despite these elements only being used if they
  
  are > 0).
  Reviewed-by : Ridley Combs <rcombs@rcombs.me>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/matroskadec.c