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• Change the Sample/Pixel aspect ratio of video with least possible video re-encoding

  27 août 2022, par PiTao

  I need to have some mp4 videos with square sample (pixel) aspect ratio (1:1) i.e. square pixels. However, as ffprobe shows my video has PAR of 59:54.

  


  I have tried using this command :

  


  ffmpeg  -i in.mp4 -c copy -bsf:v "h264_metadata=sample_aspect_ratio=1/1" out.mp4


  


  but still the PAR has not changed in my downstream applicaiton or as I checked it with the ffprobe :

  


  ffprobe version n5.1 Copyright (c) 2007-2022 the FFmpeg developers
  built with gcc 12.1.1 (GCC) 20220730
  configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-amf --enable-avisynth --enable-cuda-llvm --enable-lto --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmfx --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librav1e --enable-librsvg --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-libzimg --enable-nvdec --enable-nvenc --enable-shared --enable-version3
  libavutil      57. 28.100 / 57. 28.100
  libavcodec     59. 37.100 / 59. 37.100
  libavformat    59. 27.100 / 59. 27.100
  libavdevice    59.  7.100 / 59.  7.100
  libavfilter     8. 44.100 /  8. 44.100
  libswscale      6.  7.100 /  6.  7.100
  libswresample   4.  7.100 /  4.  7.100
  libpostproc    56.  6.100 / 56.  6.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'vimeo_11261121.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf59.27.100
  Duration: 00:00:52.36, start: 0.000000, bitrate: 519 kb/s
  Stream #0:0[0x1](eng): Video: h264 (High 4:4:4 Predictive) (avc1 / 0x31637661), yuv444p(progressive), 720x576 [SAR 1:1 DAR 5:4], 382 kb/s, SAR 59:54 DAR 295:216, 25 fps, 25 tbr, 12800 tbn (default)
    Metadata:
      handler_name    : Apple Video Media Handler
      vendor_id       : [0][0][0][0]
  Stream #0:1[0x2](eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 130 kb/s (default)
    Metadata:
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]


  


  If I not mistaken, the ffmpeg only changes the metadata and not the actual PAR. Is it possible to change the PAR (sample aspect ratio) preferably without much re-encoding ?

  


• ffmpeg - Crazy artifacts after concatenation

  26 août 2022, par JohnWick

  

  


  Running the following command :

  


  ffmpeg -i video.mp4 -f segment -segment_times 60,120 -reset_timestamps 1 -c copy out%03d.mp4


  


  Generates the files out000.mp4, out001.mp4, out002.mp4 seen in the image.

  


  Here is the ffprobe for the source, video.mp4

  


  ffprobe version 2022-08-22-git-f23e3ce858-full_build-www.gyan.dev Copyright (c) 2007-2022 the FFmpeg developers
  built with gcc 12.1.0 (Rev2, 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-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
  libavutil      57. 33.101 / 57. 33.101
  libavcodec     59. 42.102 / 59. 42.102
  libavformat    59. 30.100 / 59. 30.100
  libavdevice    59.  8.101 / 59.  8.101
  libavfilter     8. 46.103 /  8. 46.103
  libswscale      6.  8.103 /  6.  8.103
  libswresample   4.  8.100 /  4.  8.100
  libpostproc    56.  7.100 / 56.  7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf59.30.100
  Duration: 00:26:04.73, start: 0.000000, bitrate: 2234 kb/s
  Stream #0:0[0x1](und): Video: hevc (Main) (hev1 / 0x31766568), yuv420p(tv, progressive), 1080x1920 [SAR 1:1 DAR 9:16], 2098 kb/s, 29.99 fps, 30 tbr, 15360 tbn (default)
    Metadata:
      handler_name    : VideoHandler
      vendor_id       : [0][0][0][0]
  Stream #0:1[0x2](und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      vendor_id       : [0][0][0][0]


  


  I then run the following command :

  


  ffmpeg -i out001.mp4 -vf hflip -c:v hevc_nvenc flipped.mp4


  


  And enter this into concat.txt :

  


  file 'out000.mp4'
file 'flipped.mp4'
file 'out002.mp4'


  


  And finally run the command

  


  ffmpeg -f concat -safe 0 -i concat.txt -c copy joined.mp4


  


  The video plays, but between the start and end timestamps of flipped.mp4 within joined.mp4, it is unwatchable with artifacts such as this :

  


  

  


  If I open flipped.mp4 in VLC, the video plays just fine. The artifacts only appear in the concatenated video.

  


• avformat/mov : Check count sums in build_open_gop_key_points()

  28 juillet 2022, par Michael Niedermayer

  avformat/mov : Check count sums in build_open_gop_key_points()
  Fixes : ffmpeg.md
  
  Fixes : Out of array access
  
  Fixes : CVE-2022-2566
  Found-by : Andy Nguyen <theflow@google.com>
  
  Found-by : 3pvd <3pvd@google.com>
  
  Reviewed-by : Andy Nguyen <theflow@google.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/mov.c