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• Linking VLC build to ffmpeg build libraries

  14 mars 2017, par gatorface

  I’m receiving the following error message when attempting to build VLC :

  checking for mad_bit_init in -lmad... yes
checking for MPG123... yes
checking for libavutil variant... libav
checking for GST_APP... yes
checking for GST_VIDEO... yes
checking for AVCODEC... no
configure: error: Requested 'libavcodec >= 57.16.0' but version of libavcodec is 56.1.0. Pass --disable-avcodec to ignore this error.

  I am running the command (first step of Configuration from link below, I did the contrib method and built everything else as well) :

  ./configure

  So let’s get the obvious out of the way : I’m missing the most recent version of libavcodec (v57). Using --disable-avcodec is not a viable solution. Doing a quick apt-file search libavcodec I’m seeing that for debian/jessie the latest version published is libavcodec56, not 57. I did also notice that libavcodec57 was available for installation with ffmpeg here https://ffmpeg.org/download.html

  I actually needed to also build ffmpeg from source. So I did that, worked my way through the dependencies without too much trouble using the guide linked to below.

  So here is my issue : After building and doing a make install of ffmpeg, I still get that error above, despite having the latest libavcodec freshly compiled.

  So my question is : since I used that guide, I am still getting the error when building vlc. I see that the lib exists her : /root/ffmpeg_build/lib/libavcodec.a, and I figured make install would put it where it needs to be. Is there some other compile flag I can set while compiling vlc to point it to that lib directory to look for libavcodec ?

  ffmpeg build : https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu
  vlc build : https://wiki.videolan.org/UnixCompile/

  ---

  UPDATE : tried this, still getting the error message : PKG_CONFIG_PATH="/root/ffmpeg_build/lib:$PKG_CONFIG_PATH" LD_LIBRARY_PATH="/root/ffmpeg_build/lib:$LD_LIBRARY_PATH" ./configure

  ---

  UPDATE2 : tried this, still getting the error message : ./configure --libdir="/root/ffmpeg_build/lib:$LIBDIR"

  ---

  UPDATE3 : I tried merging my ffmpeg libs into my vlc libs and may have made things worse. My ffmpeg libs lived here : /root/ffmpeg_build/lib
  My vlc build (contrib builds as well) lived here : /opt/vlc/

  So I merged them with my existing vlc contrib lib :

  cp /root/ffmpeg_build/lib/* /opt/vlc/contrib/x86_64-linux-gnu/lib/
cp /root/ffmpeg_build/lib/pkgconfig/* /opt/vlc/contrib/x86_64-linux-gnu/lib/pkgconfig/

  Then ran configure :
  ./configure --with-contrib=contrib/x86_64-linux-gnu

  Which finally worked, but now I get this error when I try to make :

  Now I get the error :
  /usr/bin/ld: /opt/vlc/contrib/x86_64-linux-gnu/lib/libavformat.a(allformats.o): relocation R_X86_64_32 against `ff_a64_muxer' can not be used when making a shared object; recompile with -fPIC

• Duplicate input stream into many output streams

  10 juin 2017, par Farshad

  I want to catch my ip camera stream and distribute it into for example 10 different streams with ffmpeg ? How can i do that ? I have checked here but nothing helpful.

  Is it possible or is there any better option ?

• Python VTK, how to record a video ?

  15 avril 2016, par Maksim Surov

  I am trying to record a video of VTK 3D animation using ffmpeg. The example I found http://www.itk.org/Wiki/VTK/Examples/Cxx/Video/FFMPEG is a bit strange for me, because it does not create a render, so it is not clear how to attach actors in this case. So, my question is how to connect vtkRenderer to vtkFFMPEGWriter ? I wrote a simplified example

  import vtk
  
  
  
  # draw a plane
  
  plane_source = vtk.vtkPlaneSource()
  
  plane_source.SetCenter(0, 0, 0)
  
  plane_source.SetNormal(0, 0, 1)
  
  plane_mapper = vtk.vtkPolyDataMapper()
  
  plane_mapper.SetInput(plane_source.GetOutput())
  
  plane_actor = vtk.vtkActor()
  
  plane_actor.SetMapper(plane_mapper)
  
  
  
  # create render
  
  render = vtk.vtkRenderer()
  
  renWin = vtk.vtkRenderWindow()
  
  renWin.AddRenderer(render)
  
  renWin.SetSize(800, 600)
  
  renInter = vtk.vtkRenderWindowInteractor()
  
  renInter.SetRenderWindow(renWin)
  
  render.AddActor(plane_actor)
  
  renWin.Render()
  
  renInter.Initialize()
  
  
  
  # set callback
  
  def cb(interactor, event):
  
      global plane_actor
  
      plane_actor.RotateZ(0.1)
  
      interactor.GetRenderWindow().Render()
  
  
  
  renInter.AddObserver('TimerEvent', cb)
  
  timerId = renInter.CreateRepeatingTimer(100);
  
  
  
  # put something here?
  
  writer = vtk.vtkFFMPEGWriter()
  
  # ??? writer.SetInputConnection(...)
  
  writer.SetFileName("test.avi")
  
  writer.Start()
  
  
  
  # run
  
  renInter.Start()