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• Build error caused by missing library arc4random

  25 mai 2016, par Omega1001

  I’m currently working on a Streaming framework, and decided to use ffmpeg to encode and or decode my Video and or Audio.

  So i clicked through https://ffmpeg.org for the api files, and downloaded the statically linked version only to find out it actually contained a .exe (I use Windows in development, but plan on using Linux in production) instead of one or more dll’s and header informations.

  Since i don’t think i can use the ’exe’ as replacement for an dll, i cloned the git source, and tried to compile it myself.

  Then, while compiling i run into this error :

  CC  libavutil/random_seed.o
  
  libavutil/random_seed.c: In function 'av_get_random_seed':
  
  libavutil/random_seed.c:130:12: error: implicit declaration of function 'arc4random' [-Werror=implicit-function-declaration]
  
       return arc4random();
  
              ^
  
  cc1: some warnings being treated as errors
  
  common.mak:60: recipe for target 'libavutil/random_seed.o' failed
  
  make: *** [libavutil/random_seed.o] Error 1

  As far as I can tell, this means that I’m missing the library arc4random, so I started searching for this lib, and found absolutly nothing, besides the fact that this library is somehow Apple related..., but no dll’s and stuff or sources to compile it myself.

  I use cygwin and its GCC to compile on 64-Bit windows 7 Machine.

  Can anyone hint me to some location where I can get this missing library, or some other possibility to get ffmpeg as library into my project ?
  (I would prefer something I can link statically , since this project is meant to be a lib by itself)

  Maybe is there a way I can make use of that downloaded exe of ffmpeg, since i can borrow its headers from the source I cloned from Git ?

  Any Hint appreciated.

  Best Regards,

  Jannik Adam

• Using libav (ffmpeg), how to decode a video file directly to a GPU texture ?

  15 janvier 2023, par GaryO

  I'm using ffmpeg's libav to decode video files on Mac. For supported codecs, it says it can use the Mac VideoToolbox framework to hardware-accelerate the decoding.&#xA;Can I get the result of that decode directly as a Metal or CoreVideo buffer or texture, in GPU memory ? My plan is to process it with compute shaders before sending it to the screen and I'd like to maximize framerate by removing CPU<->GPU transfers.

  &#xA;

  Is there an example of doing this anywhere ?

  &#xA;

• Stream a website to a mp4 (rendering html to a mp4)

  25 septembre 2022, par Muppet1856

  I am trying to composite a website (which contains JavaScript and as a result is updating regularly) with a video feed. My goal is to do it on virtual hosted Linux server (my plan is to use Ubuntu, but I am flexible) - I am not interested in solutions utilizing OBS or the like as my solution would be headless.

  &#xA;

  The problem I am facing is how to output the website to a video stream from a command line.

  &#xA;

  The site I want to capture is https://vscore.ch/home and I would like to render it in a way that I can feed it to ffmpeg where I can composite it with the live game video that is being delivered via RTMP.

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