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• Compile FFmpeg Zeranoe Build with Visual Studio 2013

  19 janvier 2016, par mFeinstein

  I downloaded the most recent Zeranoe dev build here, included the header files to my code, placed extern "C" around the includes, since this is a C++ project and FFmpeg is a C library, and added the libs to Visual Studio as well, and I get this linker error :

  1>Camera.obj : error LNK2019 : unresolved external symbol _av_free referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _av_freep referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _av_frame_alloc referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _av_frame_free referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _avcodec_register_all referenced in function __catch$ ??0Camera@MicroDFV_Camera@@QAE@V ?$basic_string@DU ?$char_traits@D@std@@V ?$allocator@D@2@@std@@0PAX@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _avcodec_alloc_context3 referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _avcodec_open2 referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _avcodec_close referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _av_init_packet referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _av_packet_unref referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _avcodec_find_encoder referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _avcodec_encode_video2 referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _av_opt_set referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>Camera.obj : error LNK2019 : unresolved external symbol _av_image_alloc referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
  1>M :\Desktop\OpenCVTest\Debug\OpenCVTest.exe : fatal error LNK1120 : 14 unresolved externals

  Searching here and on Google I found many recommendations, such as to add #pragma comment(lib,...), and that the libs are static, so their order is important, and none of this helps.

  So I scratched my head even more and realized that the Zeranoe build is made with MinGW-w64, so probably it won’t link with Visual Studio. I inspected the lib using dumpbin and the symbols on the libs don’t have the underscore, so I am pretty sure it won’t work.

  The other Zeranoe builds for Windows don’t have libs, they are just plain .exe or exe + .dll.

  Will I have to make my own VS2013 build of FFmpeg to link it, or is there some alternative way ?

• Visual C++ linker can't resolve FFmpeg's external symbols

  25 février 2016, par JustPingo

  I’m making a C++ program and I want to use FFmpeg pre-built for x64, which is a C-compiled library.
  I’m using this code in order to include its header :

  extern "C" {
  
      #include "libavcodec/avcodec.h"
  
      #include "libavformat/avformat.h"
  
  
  
      #pragma comment (lib,"G:/Documents/ffmpeg/lib/avcodec.lib")
  
      #pragma comment (lib,"G:/Documents/ffmpeg/lib/avformat.lib")
  
  }

  I’m then calling the symbols like I would do for a normal function, for example with av_interleaved_write_frame(out->formatContext, &packet);

  However, when I try to compile it with Visual Studio 2015’s built-in C++ compiler, I get a lot of error like

  Error   LNK2019 unresolved external symbol _av_write_trailer referenced in function "void __cdecl closeArenaVideo(struct VideoOutput *)" (?closeArenaVideo@@YAXPAUVideoOutput@@@Z)  Sparta2 c:\Users\Théo\documents\visual studio 2015\Projects\Sparta2\Sparta2\video.obj   

  for basically any of the symbols I’m refering to.

  I tried to import everything in Visual Studio, to compile with command-line, to manually put FFmpeg’s libraries in the default libraries path, without success.

  Thank you in advance !

• Error Link 2001 libavformat.a(tls_schannel.o) when building any ffmpeg project in Visual Studio 2010

  15 mai 2017, par M.Taha

  I have just built ffmpeg latest version 3.0 and when I am trying to build ffmpeg related project in Visual Studio 2010, it gives this error :

  libavformat.a(tls_schannel.o) : error LNK2001 : unresolved external symbol _FreeContextBuffer@4

  1>libavformat.a(tls_schannel.o) : error LNK2001 : unresolved external symbol _InitializeSecurityContextA@48

  1>libavformat.a(tls_schannel.o) : error LNK2001 : unresolved external symbol __imp__ApplyControlToken@8

  1>libavformat.a(tls_schannel.o) : error LNK2001 : unresolved external symbol __imp__FreeCredentialsHandle@4

  1>libavformat.a(tls_schannel.o) : error LNK2001 : unresolved external symbol __imp__DeleteSecurityContext@4

  1>libavformat.a(tls_schannel.o) : error LNK2001 : unresolved external symbol _AcquireCredentialsHandleA@36

  1>libavformat.a(tls_schannel.o) : error LNK2001 : unresolved external symbol _DecryptMessage@16

  1>libavformat.a(tls_schannel.o) : error LNK2001 : unresolved external symbol _EncryptMessage@16

  1>libavformat.a(tls_schannel.o) : error LNK2001 : unresolved external symbol _QueryContextAttributesA@12

  My project is able to build an older version from 2014. When I search in 2014 ffmpeg there is no tls_schannel.c present.

  But I have to make project now with latest ffmpeg3.0.
  So please tell me how to make it work.