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• avutil/common : add av_rint64_clip

  1er novembre 2015, par Ganesh Ajjanagadde

  avutil/common : add av_rint64_clip
  The rationale for this function is reflected in the documentation for
  
  it, and is copied here :
  Clip a double value into the long long amin-amax range.
  
  This function is needed because conversion of floating point to integers when
  
  it does not fit in the integer’s representation does not necessarily saturate
  
  correctly (usually converted to a cvttsd2si on x86) which saturates numbers
  
  > INT64_MAX to INT64_MIN. The standard marks such conversions as undefined
  
  behavior, allowing this sort of mathematically bogus conversions. This provides
  
  a safe alternative that is slower obviously but assures safety and better
  
  mathematical behavior.
  
  API :
  
  @param a value to clip
  
  @param amin minimum value of the clip range
  
  @param amax maximum value of the clip range
  
  @return clipped value
  Note that a priori if one can guarantee from the calling side that the
  
  double is in range, it is safe to simply do an explicit/implicit cast,
  
  and that will be far faster. However, otherwise this function should be
  
  used.
  avutil minor version is bumped.
  Reviewed-by : Ronald S. Bultje <rsbultje@gmail.com>
  
  Signed-off-by : Ganesh Ajjanagadde <gajjanagadde@gmail.com>
  

  • [DH] libavutil/common.h
  • [DH] libavutil/version.h

• build : Allow generating dependencies as a side-effect of assembling

  13 octobre 2016, par Diego Biurrun

  build : Allow generating dependencies as a side-effect of assembling
  (Cherry-picked from libav commit 3c0efbd03349ae68d3a25a082222652a102e3fd4)
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] configure
  • [DH] ffbuild/common.mak

• Best way to record a HTML Canvas/WebGL animation server-side into a video ?

  19 novembre 2022, par Abhinav

  I have a set of animations which I can make in Canvas (fabric.js) or WebGL (three.js). I need to record them automatically, server-side, through a script and output a video file.

  



  The animations include :
  

  



  

  1. Pictures
     

  


  2. Videos (with audio)
     

  


  3. Other animations/effects

  


  



  I have researched a lot during last few months on this.

  



  Results
  
1. Use PhantomJS + FFMPEG
  
Run HTML Canvas animations on headless browser(PhantomJS) and record with FFMPEG. Here the issue is PhantomJS supports neither WebGL nor Video element. http://phantomjs.org/supported-web-standards.html

  
2. Use Websockets to send data back to server using DataURL
  
Here again, we will need to run the animations on browser (which we can't because we have to do everything on server).

  
3. Use node-canvas
  
This is a library by TJ Holowaychuk which allows rendering HTML Canvas on Node.js. But it has its own limitations plus I haven't really explored this field much. 
(If someone could shed more light on this library)

  



  If anyone has done it before or can guide me somewhere useful.
  
All we need to do is use some data to create animations and record it into a video, everything on server side.