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• Android Studio link prebuilt library .so error

  15 juin 2016, par Zhou Yufeng

  I’m developing an Android app using FFmpeg. I have built FFmpeg into *.so files and put them into jniLibs as follows :

  src

  —main

  ----jniLibs

  ------armeabi

  --------libavcodec-57.so

  --------libavformat-57.so

  --------xx.so

  While in grade script, abifilter of ndk is armeabi.

  In java files, I have succeeded load these .so files and the built apk also contains them. However, when I use any API (e.g. av_register_all()) of them in a .c file under src/jni folder, build error comes :

  Error :(14) undefined reference to ’av_register_all’

  Error:Execution failed for task ’:app:compileDebugNdk’.

  com.android.ide.common.process.ProcessException : org.gradle.process.internal.ExecException : Process ’command ’/Users/zhouyf/Library/Android/sdk/ndk-bundle/ndk-build’’ finished with non-zero exit value 2

  It seems that problem exists in linker. But I found answer that just putting .so files to jniLibs/armeabi will be OK.
  Do I need modify build.gradle file to link those .so files or else ?

  P.S.

  If I don’t call the API, the app will run successfully, only with warning : W/linker : libavformat-57.so : unused DT entry : type 0x6ffffffe arg 0x60e0
  W/linker : libavformat-57.so : unused DT entry : type 0x6fffffff arg 0x2

  Environment :
  Android Studio 2.1.1
  Mac OS X 10.11.5

• configure : Add link-time optimization support

  24 avril 2016, par Henrik Gramner

  configure : Add link-time optimization support
  Enabled by using the —enable-lto configuration option.
  May give a slight performance improvement in some cases, but it can
  
  also reduce performance in other cases (largely compiler-dependant)
  
  so don’t enable it by default. It also makes compilation (and linking
  
  in particular) a fair bit slower.
  Note that some older versions of GNU binutils will incorrectly warn
  
  about "memset used with constant zero length parameter" when linking
  
  using LTO. This is due to a bug in binutils and can safely be ignored.
  

  • [DH] configure

• What libraries needed to link FFMPEG in ubuntu 64bit ?

  12 mai 2016, par mofed8461

  After compile FFMPEG, and use it in my project, what system libraries do i need to link in order to use FFMPEG in my C++ project so its not generating "undefined reference error" ?

  in Mac OS X i usually link these libraries :

  FIND_LIBRARY(LIB_Z libz.1.dylib)
  
  FIND_LIBRARY(LIB_BZ2 libbz2.1.0.dylib)
  
  FIND_LIBRARY(LIB_ICONV libiconv.2.dylib)
  
  FIND_PACKAGE(CoreVideo REQUIRED)
  
  FIND_PACKAGE(CoreMedia REQUIRED)
  
  FIND_PACKAGE(Foundation REQUIRED)
  
  FIND_PACKAGE(AVFoundation REQUIRED)
  
  FIND_PACKAGE(IOKit REQUIRED)
  
  FIND_PACKAGE(Cocoa REQUIRED)
  
  FIND_PACKAGE(Security REQUIRED)
  
  FIND_PACKAGE(CoreFoundation REQUIRED)
  
  FIND_PACKAGE(VideoDecodeAcceleration REQUIRED)
  
  FIND_PACKAGE(VideoToolbox REQUIRED)

  but in Ubuntu i don’t know what to link ?!