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• x264 options for colorprim

  25 septembre 2018, par Kumar Swaminathan

  I have a source with the following color characteristics (as determined by ffprobe using "ffprobe -v error -show_format -show_streams source") colormatrix=smpte170m:colorprim=reserved:transfer=reserved.

  I would like to preserve this and so I encoded with ffmpeg with libx264 by specifying the following x264 specific options:

  "-vcodec libx264 -profile:v baseline -level 3.1 -b:v 2400k -preset medium -x264opts ref=3:keyint=90:colormatrix=smpte170m:colorprim=reserved:transfer=reserved -r 30000/1001"

  But now I get an error =>

  [libx264 @ 0x2234820] bad value for 'colorprim': 'reserved'

  Error initializing output stream 0:1 -- Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height

  What should the ideal mapping here be to preserve the input color characteristics ?

• Conversion from mjpeg to mp4 (libx264) with FFmpeg

  19 septembre 2018, par salud

  If you convert from mjpeg to mp4 (libx264) with FFmpeg, Playback can not be performed on Windows · Mac.

  Thumbnails are not displayed on the icon. However, with the HTML5 Video tag, playback is possible.

  Why? Please tell me if you understand. Thank you.

  ffmpeg -i source_file.mov -b 4000k -vcodec libx264 destination_file.mp4
  

• Export dynamic metadata using x265

  28 août 2018, par nam

  I am working on ffmpeg and x265 for video encoding. From the release note of x265:

  HDR10+ supported. Dynamic metadata may be either supplied as a bitstream via the userSEI field of x265_picture, or as a json jile that can be parsed by x265 and inserted into the bitstream; use --dhdr10-info to specify json file name, and --dhdr10-opt to enable optimization of inserting tone-map information only at IDR frames, or when the tone map information changes.

  But I dont know how to export the dynamic metadata from a video sequence as a userSEI or json file. Hope to get solution from you.

• FFmpeg/x264 “subq” or “subme” Settings

  26 août 2018, par RRN

  I am using FFmpeg 4, FFmpeg x264 has an option called “subq” or “subme”, the document mentioned the default is ‘6’, but I tried to skip this option, then if I use “MediaInfo” to check the output video, the default should be ‘0’ instead of ‘6’. The document doesn’t’ mention about ’0’, anybody knows?

• What is the cause of this green and yellow ffmpeg artifact ?

  17 juillet 2018, par Suever

  I'm trying to convert a series of image frames into a video with ffmpeg. For some of the image series, I am getting a strange yellow/green artifact and I'm not sure what setting in the conversion is causing the artifact or the best way to fix it.

  The command I'm using for the conversion is

  ffmpeg -f concat -safe 0 -i inputs.txt -c:v libx264 -pix_fmt yuv420p -r 10 -vf "scale=1024:-2" -movflags +faststart video.mp4
  

  A reproducible example with three image files and an associated inputs.txt file indicating the files and associated durations can be downloaded here (Dropbox link)

  Here's the resulting artifact

  

  And the GIF of the output

  

  What settings could be causing this artifact, and what can I do to try to reduce/remove the artifact from the video? This happens on both versions of ffmpeg that I have tried:

  ffmpeg version 3.4.1 Copyright (c) 2000-2017 the FFmpeg developers
    built with Apple LLVM version 9.0.0 (clang-900.0.39.2)
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.4.1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gpl --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
  
  ffmpeg version 3.1-tessus Copyright (c) 2000-2016 the FFmpeg developers
    built with Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn)
    configuration: --cc=/usr/bin/clang --prefix=/opt/ffmpeg --as=yasm --extra-version=tessus --enable-avisynth --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopus --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzmq --enable-version3 --disable-ffplay --disable-indev=qtkit --disable-indev=x11grab_xcb
  

  Any insight is appreciated.