FFmpeg-Android

Herein lies scripts and instructions for compiling FFmpeg for Android with RTMP support. Much thanks to Chris Ballinger and Liu Feipeng.

Instructions

Optional RTMP support dependencies

If you'd like to build FFmpeg with --enable-librtmp, first download and build OpenSSL and librtmp:

OpenSSL

1. The GuardianProject have a great project that makes building as simple as invoking ndk-build.

librtmp

2. Clone RTMPDump, and copy build_librtmp_for_android.sh into the ./librtmp subdirectory.

    $ git clone git://git.ffmpeg.org/rtmpdump
    $ cp /path/to/build_librtmp_for_android.sh ./rtmpdump/librtmp
    $ ./rtmpdump/librtmp/build_librtmp_for_android.sh
   

3. Modify the header variables in build_librtmp_for_android.sh as appropriate:

    #build_librtmp_for_android.sh
    NDK=/path/to/your/android-ndk-r9c
    SYSROOT=$NDK/platforms/android-19/arch-arm/
    TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/darwin-x86_64
    OPENSSL_DIR=/path/to/your/openssl-android/
    ...
   

Building FFmpeg

1. Download the FFmpeg source you desire (This process is tested with 2.1.3)

2. Modify configure ever so slightly to conform to the Android NDK build system:

    # ffmpegX.X.X/configure
    ...
    # Replace the following lines:
    
    #SLIBNAME_WITH_MAJOR='$(SLIBNAME).$(LIBMAJOR)'
    #LIB_INSTALL_EXTRA_CMD='$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"'
    #SLIB_INSTALL_NAME='$(SLIBNAME_WITH_VERSION)'
    #SLIB_INSTALL_LINKS='$(SLIBNAME_WITH_MAJOR) $(SLIBNAME)'
    
    # With: 
    
    SLIBNAME_WITH_MAJOR='$(SLIBPREF)$(FULLNAME)-$(LIBMAJOR)$(SLIBSUF)'
    LIB_INSTALL_EXTRA_CMD='$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"'
    SLIB_INSTALL_NAME='$(SLIBNAME_WITH_MAJOR)'
    SLIB_INSTALL_LINKS='$(SLIBNAME)'
   

If building with RTMP support: Also modify the following line of configure:

    # Replace this:
    enabled librtmp    && require_pkg_config librtmp librtmp/rtmp.h RTMP_Socket
    # With this:
    enabled librtmp    && require librtmp librtmp/rtmp.h RTMP_Socket -L/path/to/rtmpdump/librtmp/android/arm/lib -lrtmp

3. Copy build_ffmpeg_for_android.sh or build_ffmpeg_with_librtmp_for_android.sh to ffmpegX.X.X/ and run! a. Make sure the script is executable:

   	$ sudo chmod +x build_ffmpeg_for_android.sh    
   

   b. Make any desired changes to build_ffmpeg_for_android.sh per your build target. c. Run!

   	$ ./build_ffmpeg_for_android.sh	
   	# or to build with debugging symbols:
   	$ ./build_ffmpeg_debug_for_android.sh
   

The result will be a collection of static libraries and headers at ffmpegX.X.X/android/

Note on Building with Debugging Symbols

We had to pass the -gdwarf-2 flag to gcc to properly generate debugging symbols for the ffmpeg libraries. A lot was going on, and perhaps instead something yet unexplained happened at a sub-atomic level.