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• lavc/vvc : Prevent overflow in chroma QP derivation

  9 juin 2024, par Frank Plowman

  lavc/vvc : Prevent overflow in chroma QP derivation
  On the top of p. 112 in VVC (09/2023) :
  It is a requirement of bitstream conformance that the values of
  
  qpInVal[ i ][ j ] and qpOutVal[ i ][ j ] shall be in the range
  
  of −QpBdOffset to 63, inclusive for i in the range of 0 to
  
  numQpTables − 1, inclusive, and j in the range of 0 to
  
  sps_num_points_in_qp_table_minus1[ i ] + 1, inclusive.
  Additionally, don't discard the return code from sps_chroma_qp_table.
  Signed-off-by : Frank Plowman <post@frankplowman.com>
  

  • [DH] libavcodec/vvc/ps.c

• avformat/dashdec : Check whitelist

  15 janvier, par Michael Niedermayer

  avformat/dashdec : Check whitelist
  Fixes : CVE-2023-6602, V. DASH Playlist SSRF
  Found-by : Harvey Phillips of Amazon Element55 (element55)
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/dashdec.c

• FFmpeg - Overlay multiple layers of transparent webm files [closed]

  27 octobre 2023, par Jens

  I am trying to overlay multiple layers ( up to 8 layers ) of transparent webm files to an mp4 file.

  


  If I do this for 2 layers, it works but ignores the alpha channel.

  


  ffmpeg  -i 1.webm -i 2.webm  -c:a copy -filter_complex "[0:v][1:v] overlay=0:0:enable='between(t,0,20)'" output.mp4


  


  I specify libvpx-vp9 to get the alpha channel as well

  


  ffmpeg -c:v libvpx-vp9 -i 1.webm -c:v libvpx-vp9 -i 2.webm -c:a copy -filter_complex "[0:v][1:v] overlay=0:0:enable='between(t,0,20)'" output.mp4


  


  Then I get an error.

  


  [libvpx-vp9 @ 0x7f9bd8d04840] Failed to decode frame: Unspecified internal error
    Last message repeated 3 times
[libvpx-vp9 @ 0x7f9bd8d04840] Failed to decode frame: Bitstream not supported by this decoder
    Last message repeated 8 times
[matroska,webm @ 0x7f9bd8f04880] Could not find codec parameters for stream 0 (Video: vp9 (libvpx-vp9) (Profile 3), none, 1080x1080): unspecified pixel format
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
Input #0, matroska,webm, from '1.webm':
  Metadata:
    encoder         : WS Matroska Muxer
    creation_time   : 2023-09-11T14:55:34.000000Z
  Duration: 00:00:20.00, start: 0.000000, bitrate: 1775 kb/s
  Stream #0:0: Video: vp9 (Profile 3), none, 1080x1080, SAR 1:1 DAR 1:1, 30 fps, 30 tbr, 1k tbn (default)
    Metadata:
      alpha_mode      : 1
  Stream #0:1: Audio: vorbis, 44100 Hz, stereo, fltp (default)

and

Failed to decode frame: Unspecified internal error
Error while decoding stream #0:0: Invalid data found when processing input
Cannot determine format of input stream 0:0 after EOF


  


  I have tried to increasing the value for the 'analyzeduration' and 'probesize', but it makes no difference.

  


  ffprobe of 1.webm

  


  ffprobe version 6.0 Copyright (c) 2007-2023 the FFmpeg developers
  built with Apple clang version 14.0.3 (clang-1403.0.22.14.1)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/6.0-with-options_4 --enable-shared --cc=clang --host-cflags= --host-ldflags= --enable-gpl --enable-libaom --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-libsnappy --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-demuxer=dash --enable-opencl --enable-audiotoolbox --enable-videotoolbox --disable-htmlpages --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfdk-aac --enable-libgme --enable-libgsm --enable-libmodplug --enable-libopenh264 --enable-libopenjpeg --enable-libopenmpt --enable-librav1e --enable-libsvtav1 --enable-librist --enable-librsvg --enable-librtmp --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtesseract --enable-libtwolame --enable-libvidstab --enable-libvmaf --enable-libwebp --enable-libxml2 --enable-libxvid --enable-libzimg --enable-libzmq --enable-openssl --enable-nonfree --enable-libjack --enable-indev=jack --enable-version3 --enable-libopencore-amrnb --enable-libopencore-amrwb
  libavutil      58.  2.100 / 58.  2.100
  libavcodec     60.  3.100 / 60.  3.100
  libavformat    60.  3.100 / 60.  3.100
  libavdevice    60.  1.100 / 60.  1.100
  libavfilter     9.  3.100 /  9.  3.100
  libswscale      7.  1.100 /  7.  1.100
  libswresample   4. 10.100 /  4. 10.100
  libpostproc    57.  1.100 / 57.  1.100
Input #0, matroska,webm, from '1.webm':
  Metadata:
    encoder         : WS Matroska Muxer
    creation_time   : 2023-09-11T14:55:34.000000Z
  Duration: 00:00:20.00, start: 0.000000, bitrate: 1775 kb/s
  Stream #0:0: Video: vp8, yuv420p(progressive), 1080x1080, SAR 1:1 DAR 1:1, 30 fps, 30 tbr, 1k tbn (default)
    Metadata:
      alpha_mode      : 1
  Stream #0:1: Audio: vorbis, 44100 Hz, stereo, fltp (default)


  


  Any ffmpeg wizards with an idea ?