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• avformat : make avformat_network_init() explicitly optional

  16 janvier 2018, par wm4

  avformat : make avformat_network_init() explicitly optional
  It was sort of optional before - if you didn't call it, networking was
  
  initialized on demand, and an ugly warning was logged. Also, the doxygen
  
  comments threatened that it would be made strictly required one day.
  Make it explicitly optional. I would prefer to deprecate it fully, but
  
  there might still be legitimate reasons to use this. But the average
  
  user won't need it.
  This is needed only for two reasons : to initialize TLS libraries like
  
  OpenSSL and GnuTLS, and winsock.
  OpenSSL and GnuTLS were already silently initialized on demand if the
  
  global network init function was not called. They also have various
  
  thread-safety acrobatics, which make concurrent initialization within
  
  libavformat safe. In addition, the libraries are moving towards making
  
  their global init functions safe, which removes all need for central
  
  global init. In particular, GnuTLS 3.5.16 and OpenSSL 1.1.0g have been
  
  found to have safe init functions. In all cases, they use internal
  
  reference counters to avoid that the global uninit functions interfere
  
  with concurrent uses of the library by other API users who called global
  
  init.
  winsock should be thread-safe as well, and maintains an internal
  
  reference counter as well.
  Since we still support ancient TLS libraries, which do not have this
  
  fixed, and since it's unknown whether winsock and GnuTLS
  
  reinitialization is costly in any way, don't deprecate the libavformat
  
  functions yet.
  

  • [DH] doc/APIchanges
  • [DH] libavformat/avformat.h
  • [DH] libavformat/network.c
  • [DH] libavformat/network.h
  • [DH] libavformat/utils.c
  • [DH] libavformat/version.h

• FFMpeg copy stream SEI type 162 error

  13 juillet 2015, par Vishal Shah

  I am using FFMpeg to copy an RTSP stream to an RTMP stream. Both of which are network streams. This is the command I am using.

  ffmpeg -re -i rtsp ://url.to/rtsp/stream -c copy -f flv rtmp ://target.rtmp/uri/stream

  I am receiving data on the youtube live control room. But After a point I get an error like this in my FFMpeg console and then the data transfer on youtube live stops.

  SEI type 162 size 1496 truncated at 1280

  Can someone throw light on what this error means and how to resolve it ?

  Note that the RTSP stream is over the network

• How to encode HEVC HDR10 to SVT-AV1 HDR10 ?

  28 octobre 2022, par Mario Gratzi

  I'm currently trying to find a way to re-encode a HEVC HDR10 clip to SVT-AV1 HDR10 using ffmpeg but for some reason, I don't get ffmpeg to forward the HDR metadata to the AV1 clip. So the re-encoded AV1 clip always has very cold color grading, which does not make fun to watch at all...

  


  I then checked onto FastFlix, a similar tool to Handbrake which is basically a ffmpeg frontend. If I select SVT-AV1 as encoder here, and I check onto the raw ffmpeg command FastFlix generates, it seems that this also includes the grading information :

  


  -svtav1-params "color-primaries=9:transfer-characteristics=16:matrix-coefficients=9:mastering-display=G(0.2650,0.6900)B(0.1500,0.0600)R(0.6800,0.3200)WP(0.3127,0.3290)L(4000.0000,0.0050):content-light=368,226:enable-hdr=1"


  


  The problem for me is now, how do I get these grading information with my own ffmpeg command ?