Mac下为Android Studio编译Ffmpeg（一）ndk部分

本文参考http://www.roman10.net/how-to-build-ffmpeg-with-ndk-r9/。
但它只适合做编码，而且没有Android Studio配置的部分。

1、下载ndk

我下的是r10d版本。

2、解压ndk

不要解压，文件权限会出错。执行之，会自动解压，然后mv到想放的地方。我放到了”/usr/local/bin/android-ndk-r10d”（此目录之后用$NDK_DIR指代）。

3、下载Ffmpeg

我下的是2.5.3版本。

4、解压Ffmpeg

解压Ffmpeg到$NDK_DIR/sources/ffmpeg-2.5.3。

5、修改Ffmpeg编译配置

在ffmpeg-2.5.3目录下把configure文件中的这几行，目的是去掉默认生成的库名字libavcodec.so.55最后那个”55″的版本号。

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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)'

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SLIBNAME_WITH_MAJOR = '$(SLIBPREF)$(FULLNAME)-$(LIBMAJOR)$(SLIBSUF)' LIB_INSTALL_EXTRA_CMD = '$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"' SLIB_INSTALL_NAME = '$(SLIBNAME_WITH_MAJOR)' SLIB_INSTALL_LINKS = '$(SLIBNAME)'

6、编译Ffmpeg

在ffmpeg-2.5.3目录下创建文件build_android.sh。
注意前三行要按照自己的路径正确配置。

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#!/bin/bash NDK = / usr / local / android - ndk - r10d SYSROOT = $ NDK / platforms / android - 15 / arch - arm / TOOLCHAIN = $ NDK / toolchains / arm - linux - androideabi - 4.9 / prebuilt / darwin - x86_64 function build_one { . / configure \      -- prefix = $ PREFIX \      -- enable - shared \      -- disable - static \      -- disable - doc \      -- disable - ffmpeg \      -- disable - ffplay \      -- disable - ffprobe \      -- disable - ffserver \      -- disable - avdevice \      -- disable - doc \      -- disable - symver \      -- cross - prefix = $ TOOLCHAIN / bin / arm - linux - androideabi - \      -- target - os = linux \      -- arch = arm \      -- enable - cross - compile \      -- sysroot = $ SYSROOT \      -- extra - cflags = "-Os -fpic $ADDI_CFLAGS" \      -- extra - ldflags = "$ADDI_LDFLAGS" \      $ ADDITIONAL_CONFIGURE_FLAG make clean make make install } CPU = arm PREFIX = $ ( pwd ) / android / $ CPU ADDI_CFLAGS = "-marm" build_one

保存后执行

1 2	sudo chmod + x build_android . sh . / build_android . sh

编译会花上一段时间。

7、查看编译结果

编译完成后$NDK_DIR/sources/ffmpeg-2.5.3下面会多出一个android目录，里面就是我们想要的编译好的库。

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[ cg @ local ] # ls -R android/ arm   android //arm: Android . mk include     lib   android //arm/include: libavcodec     libavfilter   libavformat   libavutil     libswresample libswscale   android //arm/include/libavcodec: avcodec . h        avfft . h          dv_profile . h      dxva2 . h          old_codec_ids . h vaapi . h          vda . h            vdpau . h          version . h        vorbis_parser . h xvmc . h   android //arm/include/libavfilter: asrc_abuffer . h    avcodec . h        avfilter . h        avfiltergraph . h buffersink . h      buffersrc . h      version . h   android //arm/include/libavformat: avformat . h avio . h      version . h   android //arm/include/libavutil: adler32 . h          avstring . h        cast5 . h            downmix_info . h    hash . h            macros . h          opt . h              replaygain . h      time . h aes . h              avutil . h          channel_layout . h error . h            hmac . h            mathematics . h      parseutils . h      ripemd . h          timecode . h attributes . h      base64 . h          common . h          eval . h            imgutils . h        md5 . h              pixdesc . h          samplefmt . h        timestamp . h audio_fifo . h      blowfish . h        cpu . h              ffversion . h        intfloat . h        mem . h              pixelutils . h      sha . h              version . h audioconvert . h    bprint . h          crc . h              fifo . h            intreadwrite . h    motion_vector . h    pixfmt . h          sha512 . h          xtea . h avassert . h        bswap . h            dict . h            file . h            lfg . h              murmur3 . h          random_seed . h      stereo3d . h avconfig . h        buffer . h          display . h          frame . h            log . h              old_pix_fmts . h    rational . h        threadmessage . h   android //arm/include/libswresample: swresample . h version . h   android //arm/include/libswscale: swscale . h version . h   android //arm/lib: libavcodec - 56.so    libavfilter - 5.so    libavformat - 56.so    libavutil - 54.so      libswresample - 1.so libswscale - 3.so      pkgconfig libavcodec . so       libavfilter . so     libavformat . so     libavutil . so       libswresample . so   libswscale . so   android //arm/lib/pkgconfig: libavcodec . pc     libavfilter . pc   libavformat . pc   libavutil . pc     libswresample . pc libswscale . pc

其中libavcodec.so、libavfilter.so、libavformat.so、libavutil.so、libswresample.so、libswscale.so都是软链，没有用，可以删掉。

8、给Ffmpeg库写Android.mk使其可用

创建$NDK_DIR/sources/ffmpeg-2.5.3/android/arm/Android.mk文件，内容如下：
要注意其中.so前面的数字应该改成你的ffmpeg版本编译出来的数字。

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LOCAL_PATH : = $ ( call my - dir ) include $ ( CLEAR_VARS ) LOCAL_MODULE : = libavcodec LOCAL_SRC_FILES : = lib / libavcodec - 56.so LOCAL_EXPORT_C_INCLUDES : = $ ( LOCAL_PATH ) / include include $ ( PREBUILT_SHARED_LIBRARY ) include $ ( CLEAR_VARS ) LOCAL_MODULE : = libavformat LOCAL_SRC_FILES : = lib / libavformat - 56.so LOCAL_EXPORT_C_INCLUDES : = $ ( LOCAL_PATH ) / include include $ ( PREBUILT_SHARED_LIBRARY ) include $ ( CLEAR_VARS ) LOCAL_MODULE : = libswscale LOCAL_SRC_FILES : = lib / libswscale - 3.so LOCAL_EXPORT_C_INCLUDES : = $ ( LOCAL_PATH ) / include include $ ( PREBUILT_SHARED_LIBRARY ) include $ ( CLEAR_VARS ) LOCAL_MODULE : = libavutil LOCAL_SRC_FILES : = lib / libavutil - 54.so LOCAL_EXPORT_C_INCLUDES : = $ ( LOCAL_PATH ) / include include $ ( PREBUILT_SHARED_LIBRARY ) include $ ( CLEAR_VARS ) LOCAL_MODULE : = libavfilter LOCAL_SRC_FILES : = lib / libavfilter - 5.so LOCAL_EXPORT_C_INCLUDES : = $ ( LOCAL_PATH ) / include include $ ( PREBUILT_SHARED_LIBRARY ) include $ ( CLEAR_VARS ) LOCAL_MODULE : = libswresample LOCAL_SRC_FILES : = lib / libswresample - 1.so LOCAL_EXPORT_C_INCLUDES : = $ ( LOCAL_PATH ) / include include $ ( PREBUILT_SHARED_LIBRARY )

至此ndk配置完毕，后面是配置Android Studio的部分。