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• lavu : Adding ARIB STD-B67 (hybrid log-gamma) enum value and transfer function.

  21 avril 2016, par Neil Birkbeck

  lavu : Adding ARIB STD-B67 (hybrid log-gamma) enum value and transfer function.
  Adding hybrid log-gamma (https://en.wikipedia.org/wiki/Hybrid_Log-Gamma)
  
  based on the standardization in ARIB STD-B67 :
  
  http://www.arib.or.jp/english/html/overview/doc/2-STD-B67v1_0.pdf
  The choice of enum value of 18 is consistent with HEVC :
  
  http://phenix.it-sudparis.eu/jct/doc_end_user/current_document.php?id=10481
  And also with latest proposal for color format in mkv :
  
  https://mailarchive.ietf.org/arch/search/?email_list=cellar&gbt=1&q=Colour+Format+proposal
  The implementation assumes a nominal input range of [0, 1], which is
  
  consistent with HEVC.
  Signed-off-by : Neil Birkbeck <neil.birkbeck@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavutil/color_utils.c
  • [DH] libavutil/pixdesc.c
  • [DH] libavutil/pixfmt.h
  • [DH] tests/ref/fate/color_utils

• pixfmt : Add ARIB STD-B76 color transfer characteristic

  15 juin 2016, par Neil Birkbeck

  pixfmt : Add ARIB STD-B76 color transfer characteristic
  Adding hybrid log-gamma (https://en.wikipedia.org/wiki/Hybrid_Log-Gamma)
  
  based on the standardization in ARIB STD-B67 :
  
  http://www.arib.or.jp/english/html/overview/doc/2-STD-B67v1_0.pdf
  The choice of enum value of 18 is consistent with HEVC :
  
  http://phenix.it-sudparis.eu/jct/doc_end_user/current_document.php?id=10481
  And also with latest proposal for color format in mkv :
  
  https://mailarchive.ietf.org/arch/search/?email_list=cellar&gbt=1&q=Colour+Format+proposal
  Signed-off-by : Vittorio Giovara <vittorio.giovara@gmail.com>
  

  • [DBH] libavcodec/options_table.h
  • [DBH] libavcodec/version.h
  • [DBH] libavutil/pixdesc.c
  • [DBH] libavutil/pixfmt.h
  • [DBH] libavutil/version.h

• Is there a direct way to render/encode Vulkan output as an ffmpeg video file ?

  13 septembre 2022, par Luiz Ventura

  I'm about to generate 2D and 3D music animations and render them to video using C++. I was thinking about using OpenGL, but I've read that, unfortunately, it is being discontinued in favour of Vulkan, which seems to offer higher performance using a GPU, but is also a lower-level API, making it more difficult to learn. I still have almost no knowledge in both OpenGL and Vulkan, beginning to learn now.

  


  My question is :

  


  is there a way to encode the Vulkan render output (showing a window or not) into a video file, preferentially through FFPMEG ? If so, how could I do that ?

  


  Requisites :

  


  

  • Speed : the decrease in performance should be nearly that of encoding the video only, not much more than that (e.g. by having to save lossless frames as images first and then encoding a video from them).

  


  • Controllable FPS and resolution : the video fps and frame resolution can be freely chosen.

  


  • Reliability, reproducibility : running a code that gives a same Vulkan output twice should result in 2 equal videos independently of the system, i.e. no dropping frames, async problems (I want to sync with audio) or whatsoever. The chosen video fps should stay fixed (e.g. 60 fps), no matter if the computer can render 300 or 3 fps.

  


  


  What I found out so far :

  


  

  • An example of taking "screenshots" from Vulkan output : it writes to a ppm image at the end, which is a binary uncompressed image file.

  


  • An encoder for rendering videos from OpenGL output, which is what I want, but using OpenGL in that case.

  


  • That Khronos includes in the Vulkan API a video subset.

  


  • A video tool to decode, demux, process videos using FFMPEG and Vulkan.

  


  • That is possible to render the output into a buffer without the need of a screen to display it.