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• ffmpeg latest visual studio builds or linking with (.a) libs

  23 juin 2013, par user1657348

  there is a problem.
  I need to link ffmpeg(particularly libavcodec) statically into visual studio 2008 project.

  I found some visual studio solutions in internet but they are very old (around 0.6 version) and i need latest version, so this way is not an option for me.

  Next, I made static build (with —enable-satic —disable-shared flags) using MinGW/msys and obtained (*.a) libraries in output.
  In Visual Studio I go to the linker properities and add to Additional Dependencies(Linker->Input) libvacodec.a and libgcc.a.
  Then i wrote simple application :

  #include 
  
  #include 
  
  extern "C"
  
  {
  
     #ifdef  __STDC_CONSTANT_MACROS
  
        #define __STDC_CONSTANT_MACROS
  
     #endif
  
        #include "libavcodec/avcodec.h"    
  
   }
  
  
  
  
  
  
  
  #include "libavformat/avformat.h"
  
  
  
        int main()
  
     {
  
      av_register_all();
  
      return 0;
  
     }

  Compilation of this code was succeeded but linking failed. There is an error was obtained :

  error  LNK2019: unresolved external symbol "void __cdecl av_register(void)" (?av_register_all@@YAXXZ) referenced in function _main.

  So, there are two questions :

  1. How to link Visual Studio application with libavcodec.a ?

  2. If it possible, where can i get visual studio solution which includes ffmpeg latest version ?

  Thanks in advance !!

• ffmpeg how convert mp3 to acc ? [closed]

  21 septembre 2012, par John Smith

  Possible Duplicate :
  ffmpeg how convert audio files in other formats ?

  code :

  $infile=$dir.'file1.mp3';
  
  $outfile_aac=$dir.'file1.acc';
  
  shell_exec("ffmpeg -i $infile -ab 256 $outfile_aac");

  code create file .acc with size = 0... Where my error ?

  FFmpeg version SVN-r12216, 
  
  Copyright (c) 2000-2008 Fabrice Bellard,
  
  et al. configuration: libavutil version: 49.6.0 libavcodec version: 51.50.1
  
  libavformat version: 52.7.0
  
  libavdevice version: 52.0.0 built on Feb 25 2008 12:40:30,
  
  gcc: 4.1.2 20070626 (Red Hat 4.1.2-14)
  
  invalid new backstep 1008 Input #0, mp3, from '/hsphere/local/home/c292729/testwork.ru/10001/ConcertMedia/1348165273ExPRoG.mp3': 
  
  Duration: 00:01:48.8,
  
  start: 0.000000,
  
  bitrate: 319 kb/s
  
  Stream #0.0: Audio: mp3, 44100 Hz, stereo, 320 kb/s Output #0, adts,
  
  to '/hsphere/local/home/c292729/testwork.ru/10001/ConcertMedia/1348165273ExPRoG.aac': 
  
  Stream #0.0:
  
  Audio: 0x0000, 44100 Hz,
  
  stereo, 64 kb/s
  
  Stream mapping: Stream #0.0 -> #0.0
  
  Unsupported codec for output stream #0.0

  what codec me need use ?

• Possible bug in OpenCV2.4 capturing frames from video

  23 septembre 2013, par Jav_Rock

  Could it be that there is a bug in OpenCV2.4 highgui for capturing frames from video in windows ?

  I installed both the precompiled libraries, the ones compiled by me, I can compile everything perfectly and I can run my programs if

  they are image based. The problem is only for videos. OpenCV crashes in this function always :

   virtual IplImage* retrieveFrame(int)
  
      {
  
          unsigned char* data = 0;
  
          int step=0, width=0, height=0, cn=0;
  
  
  
          if(!ffmpegCapture ||
  
             !icvRetrieveFrame_FFMPEG_p(ffmpegCapture,&data,&step,&width,&height,&cn)) <-------CRASHES HERE
  
             return 0;
  
          cvInitImageHeader(&frame, cvSize(width, height), 8, cn);
  
          cvSetData(&frame, data, step);
  
          return &frame;
  
      }

  This is inside the class cap_ffmpeg.cpp and is called by VideoCapture.

  I tried versions 2.4.2 and 2.4.9. My programes were working finde with opencv2

  ---

  More information

  • Windows 7

  • Build the projects with cmake (important as it could be that cmake is not building/finding the right codecs)

  • VisualStudio 9 2008

  • OpenCV 2.4.2

  EDIT

  It looks like it is actually a bug, so, how can I solve this problem and change my code to be able to read avi files ?