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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

• Create thumbnails of sections of a torrent stream

  14 juillet 2015, par Ortixx

  I’m trying to create a little application in nodejs using the torrent-stream library to create thumbnails of a video without actually having to download the entire file. I was thinking of downloading only 10 parts, out of which I would extract an image, but then the encoding comes into play : without an I-frame I cannot extract an image out of the stream, and there is no way of me knowing where the I-frame is.

  So any ideas on how to do this ? Basically I was hoping to create 10 tiny files which I could then open in ffmpeg in order to save a thumbnail (this would give me 10 thumbnails which is want I want). I’m just not sure how to handle the stream.

• I transcode using the ffmpeg library, but the resulting video playback speed is different [closed]

  25 novembre 2023, par 최용훈

  Source

  


  I'm studying ffmpeg and trying to write a C++ wrapper.

  


  The test code at the bottom of the video.cpp source in the test folder is a transcoding example, and the resulting video playback speed is about 5 times faster.

  


  Timebase and FPS are the same because they are copied and used.

  


  Why does this phenomenon occur ?

  


  similar issue

  


  I found a problem similar to mine but it didn't help

  


  I couldn't find anyone else with the same problem

  


  I referred to the transcoding example and video_encoding example in the ffmpeg tutorial.