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• lavc : implement an ATRAC9 decoder

  30 juin 2018, par Rostislav Pehlivanov

  lavc : implement an ATRAC9 decoder
  This commit implements a full ATRAC9 decoder, a simple low-delay codec
  
  developed by Sony and used in most PSVita games, some PS3 games and some
  
  PS4 games. Its similar to AAC in that it uses Huffman coded scalefactors
  
  but instead of vector quantization it just Huffman codes the spectral
  
  coefficients (in a way similar to how Opus splits band energy coding
  
  into coarse and fine precision). It opts to write rather large Huffman
  
  codes by packing several small coefficients into one Huffman coded
  
  symbol, though I don't believe this increases efficiency at all.
  
  Band extension implements SBC in a simple way, first it mirrors the
  
  lower spectrum onto the higher frequencies and then it uses one of 5
  
  filters to shape it. Noise substitution is implemented via 2 of them.
  
  Unlike previous ATRAC codecs, there's no QMF, this is a standard MDCT
  
  codec.
  Based off of the reverse engineering work of Alex Barney.
  Signed-off-by : Rostislav Pehlivanov <atomnuker@gmail.com>
  

  • [DH] Changelog
  • [DH] configure
  • [DH] libavcodec/Makefile
  • [DH] libavcodec/allcodecs.c
  • [DH] libavcodec/atrac9dec.c
  • [DH] libavcodec/atrac9tab.h
  • [DH] libavcodec/avcodec.h
  • [DH] libavcodec/codec_desc.c
  • [DH] libavcodec/utils.c
  • [DH] libavcodec/version.h

• avformat/matroskadec : Fix demuxing ProRes

  28 septembre 2019, par Andreas Rheinhardt

  avformat/matroskadec : Fix demuxing ProRes
  The structure of a ProRes frame in mov/mp4 is that of a typical atom :
  
  First a 32 bit BE size field, then a tag detailling the content. Said
  
  size field includes the eight bytes of the atom header.
  This header is actually redundant, as the size of the atom is already
  
  known from the containing atom. It is therefore stripped away when muxed
  
  into Matroska and so the Matroska demuxer has to recreate upon demuxing.
  
  But it did not account for the fact that the size field includes the
  
  size of the header and this can lead to problems when a decoder uses the
  
  in-band size field.
  Fixes ticket #8210.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] libavformat/matroskadec.c

• h264_mp4toannexb : Try to avoid four byte startcodes

  14 décembre 2019, par Andreas Rheinhardt

  h264_mp4toannexb : Try to avoid four byte startcodes
  According to the H.264 specifications, the only NAL units that need to
  
  have four byte startcodes in H.264 Annex B format are SPS/PPS units and
  
  units that start a new access unit. Before af7e953a, the first of these
  
  conditions wasn't upheld as already existing in-band parameter sets
  
  would not automatically be written with a four byte startcode, but only
  
  when they already were at the beginning of their input packets. But it
  
  made four byte startcodes be used too often as every unit that is written
  
  together with a parameter set that is inserted from extradata received a
  
  four byte startcode although a three byte start code would suffice
  
  unless the unit itself were a parameter set.
  FATE has been updated to reflect the changes. Although the patch leaves
  
  the extradata unchanged, the size of the extradata according to the FATE
  
  reports changes. This is due to a quirk in ff_h2645_packet_split which
  
  is used by extract_extradata : If the input is Annex B, the first zero of
  
  a four byte startcode is considered a part of the last unit (if any).
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/h264_mp4toannexb_bsf.c
  • [DH] tests/ref/fate/h264-bsf-mp4toannexb
  • [DH] tests/ref/fate/h264_mp4toannexb_ticket2991
  • [DH] tests/ref/fate/h264_mp4toannexb_ticket5927
  • [DH] tests/ref/fate/h264_mp4toannexb_ticket5927_2
  • [DH] tests/ref/fate/segment-mp4-to-ts