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• configure : Detect msvcrt libc with a CPP check instead of a link check

  4 décembre 2013, par Diego Biurrun

  configure : Detect msvcrt libc with a CPP check instead of a link check
  Simplifies host/target libc detection splitting.
  

  • [DH] configure

• Is it possible to link FFmpeg statically into an application built with Visual C++ ?

  29 juillet 2013, par Richard NZ

  I'm currently building and using FFmpeg on Windows and it works nicely. At present there are 5 relevant DLLs which I load and map relevant functions in as needed. However I am wondering if it is possible to avoid these DLLs by linking FFmpeg statically ?

  My initial reaction is probably not, because the FFmpeg builds are done with MinGW's GCC and any static libraries generated by those tools will be in a format incompatible with Visual C++. If anyone has looked into this before I'd be curious to know if you had any luck ?

  I did find this tool : http://www.binary-soft.com/dll2lib/dll2lib.htm. It's expensive but looks like it might do the trick as it converts a DLL directly to a static library.

  Thanks.

• Link static libraries Android.mk ffmpeg on Android

  11 août 2013, par kikuchi

  I built FFMPEG with the guardian's script (here). All went good and I have the following structure :

  jni/
  
  |-- Android.mk
  
  |-- demo.c
  
  |-- include/
  
  |   |-- libavcodec/
  
  |   |   |-- headers files
  
  |   |-- libavdevice/
  
  |   |   `-- avdevice.h
  
  |   |-- libavfilter/
  
  |   |   |-- headers files
  
  |   |-- libavformat/
  
  |   |   |-- headers files
  
  |   |-- libavresample/
  
  |   |   |-- headers files
  
  |   |-- libavutil/
  
  |   |   |-- headers files
  
  |   |-- libpostproc/
  
  |   |   |-- headers files
  
  |   |-- libswresample/
  
  |   |   |-- headers files
  
  |   |-- libswscale/
  
  |   |   |-- headers files
  
  |   `-- sox.h
  
  `-- lib/
  
      |-- libavcodec.a
  
      |-- libavdevice.a
  
      |-- libavfilter.a
  
      |-- libavformat.a
  
      |-- libavresample.a
  
      |-- libavutil.a
  
      |-- libpostproc.a
  
      |-- libsox.a
  
      |-- libswresample.a
  
      |-- libswscale.a
  
      |-- libx264.a

  Here is my Android.mk file :

  LOCAL_PATH := $(call my-dir)
  
  include $(CLEAR_VARS)
  
  
  
  FFMPEG_LIBS := $(addprefix lib/, \
  
   libavformat.a \
  
   libavcodec.a \
  
   libpostproc.a \
  
   libswscale.a \
  
   libavutil.a \
  
   x264.a )
  
  
  
  LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
  
  LOCAL_SRC_FILES := demo.c
  
  LOCAL_LDLIBS := -llog
  
  LOCAL_STATIC_LIBRARY := $(FFMPEG_LIBS)
  
  LOCAL_MODULE := demo
  
  include $(BUILD_SHARED_LIBRARY)

  And my demo.c file :

  #include 
  
  
  
  #include <libavcodec></libavcodec>avcodec.h>
  
  #include <libavformat></libavformat>avformat.h>
  
  #include <libavformat></libavformat>avio.h>
  
  #include <libswscale></libswscale>swscale.h>
  
  #include <libavutil></libavutil>avstring.h>
  
  
  
  JNIEXPORT jint JNICALL Java_com_example_ffmpeg_guardian_MainActivity_logFileInfo(JNIEnv *env, jclass this, jstring filename)
  
  {
  
      av_register_all();
  
  
  
      AVFormatContext *pFormatCtx;
  
      const jbyte *str;
  
      str = (*env)->GetStringUTFChars(env, filename, NULL);
  
  
  
      if(avformat_open_input(&amp;pFormatCtx, str, NULL, NULL)!=0)
  
          return 1;
  
      else
  
         return 2;
  
  
  
      return 0;
  
  }

  The problem is when I try to compile with the NDK (r8) I got this message :

  Compile thumb  : demo <= demo.c
  
  SharedLibrary  : libdemo.so
  
  demo.o: In function `Java_com_example_ffmpeg_guardian_MainActivity_logFileInfo':
  
  demo.c:11: undefined reference to `av_register_all'
  
  demo.c:17: undefined reference to `avformat_open_input'
  
  collect2: ld returned 1 exit status
  
  make: *** [ffmpeg-guardian/obj/local/armeabi/libdemo.so] Error 1

  After some research, this problem appears because libraries are not linked in the right order. I tried to change this order but nothing changed.

  Can Someone help me to fix this final step to get ffmpeg working on android ? Thanks !