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• lavc/vvc : Check slice structure

  10 janvier, par Frank Plowman

  lavc/vvc : Check slice structure
  The criteria for slice structure validity is similar to that of
  
  subpicture structure validity that we saw not too long ago [1].
  
  The relationship between tiles and slices must satisfy the following
  
  properties :
  * Exhaustivity.  All tiles in a picture must belong to a slice.  The
  
    tiles cover the picture, so this implies the slices must cover the
  
    picture.
  
  * Mutual exclusivity.  No tile may belong to more than one slice, i.e.
  
    slices may not overlap.
  In most cases these properties are guaranteed by the syntax.  There is
  
  one noticable exception however : when pps_tile_idx_delta_present_flag is
  
  equal to one, each slice is associated with a syntax element
  
  pps_tile_idx_delta_val[i] which "specifies the difference between the
  
  tile index of the tile containing the first CTU in the ( i + 1 )-th
  
  rectangular slice and the tile index of the tile containing the first
  
  CTU in the i-th rectangular slice" [2].  When these syntax elements are
  
  present, the i-th slice can begin anywhere and the usual guarantees
  
  provided by the syntax are lost.
  The patch detects slice structures which violate either of the two
  
  properties above, and are therefore invalid, while building the
  
  slice map.  Should the slice map be determined to be invalid, an
  
  AVERROR_INVALIDDATA is returned.  This prevents issues including
  
  segmentation faults when trying to decode,  invalid bitstreams.
  [1] : https://ffmpeg.org//pipermail/ffmpeg-devel/2024-October/334470.html
  
  [2] : H.266 (V3) Section 7.4.3.5, Picture parameter set RBSP semantics
  Signed-off-by : Frank Plowman <post@frankplowman.com>
  

  • [DH] libavcodec/vvc/ps.c

• Empty audio backends for torchaudio list audio backends, with ffmpeg installed on system libraries [closed]

  28 mars, par Alberto Agudo Dominguez

  I installed torchaudio 2.5.1 and a system install of ffmpeg on Windows and get :

  


  PS C:\Users\> ffmpeg -version
ffmpeg version 2025-01-05-git-19c95ecbff-essentials_build-www.gyan.dev Copyright (c) 2000-2025 the FFmpeg developers
built with gcc 14.2.0 (Rev1, Built by MSYS2 project)
configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-libfreetype --enable-libfribidi --enable-libharfbuzz --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-dxva2 --enable-d3d11va --enable-d3d12va --enable-ffnvcodec --enable-libvpl --enable-nvdec --enable-nvenc --enable-vaapi --enable-libgme --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband
libavutil      59. 54.101 / 59. 54.101
libavcodec     61. 31.100 / 61. 31.100
libavfilter    10.  6.101 / 10.  6.101
libswresample   5.  4.100 /  5.  4.100
libpostproc    58.  4.100 / 58.  4.100

PS C:\Users\> python
Python 3.12.5 (tags/v3.12.5:ff3bc82, Aug  6 2024, 20:45:27) [MSC v.1940 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import torchaudio
>>> torchaudio.list_audio_backends()
[]


  


  Hence ffmpeg is added to the path and recognized by the console, but not by torchaudio.

  


• avformat/iamf_parse : reject ambisonics mode > 1

  29 novembre 2024, par Michael Niedermayer

  avformat/iamf_parse : reject ambisonics mode > 1
  ambisonics mode > 1 does not initialize any layer but layer 0
  
  is unconditionally dereferenced
  Fixes : poc-2024-11
  
  Fixes : null pointer dereference
  
  Found-by : 苏童 <220235212@seu.edu.cn>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/iamf_parse.c