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This article mainly explains "how C++ compiles Android dynamic library", interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn "how C++ compiles Android dynamic library".

C++ 2.FFmpeg-4.3.2 compiles Android dynamic library (ubuntu 18.04r21b) compilation environment

Linux system:

Ubuntu18.04

NDK

Ndk/android-ndk-r21b

FFmpeg

Ffmpeg-4.3.2

File name after ffmpeg download

Ffmpeg_4.3.2.orig.tar.xz

Decompression mode

Tar xvJf ffmpeg_4.3.2.orig.tar.xz

Operate under root permission

Compiling version 4.3.2 does not need to modify the configure file to write an Android compilation script

Create a new file build_android.sh

#! / bin/bash# ndk path NDK=/home/build/workspace/hqq/vision/vision-app/ndk/android-ndk-r21b# compilation tool chain directory. Clang is used in ndk17 version above. The following is the root directory of the gccTOOLCHAIN=$NDK/toolchains/llvm/prebuilt/linux-x86_64# version number API=21# cross-compilation tree (looking for the corresponding header files and libraries) SYSROOT= "${TOOLCHAIN} / sysroot" # defines the shell method function build_android () {. / configure\-prefix=$PREFIX\-enable-shared\-- disable-static\-- enable-jni\ that executes configure -- enable-gpl\-- enable-small\-- disable-doc\-- disable-programs\-- disable-symver\-- target-os=android\-- arch=$ARCH\-- cpu=$CPU\-- cc=$CC\-- cxx=$CXX\-enable-cross-compile\-- cross-prefix=$CROSS_COMPILE\-- sysroot=$SYSROOT \-- extra-cflags= "- Os-fpic $OPTIMIZE_CFLAGS"\-- extra-ldflags= "\-- disable-asm\ $COMMON_FF_CFG_FLAGS make clean make-j16 make install} # armOUTPUT_FOLDER=armARCH=armCPU=armv7-aTOOL_CPU_NAME=armv7aTOOL_PREFIX=$TOOLCHAIN/bin/$ {TOOL_CPU_NAME}-linux-androideabiOPTIMIZE_CFLAGS="-marm-march=$CPU "PREFIX=$ {PWD} / android/$OUTPUT_FOLDERCROSS_COMPILE=$TOOLCHAIN/bin/arm-linux- Androideabi-CC=$ {TOOL_PREFIX} ${API}-clangCXX=$ {TOOL_PREFIX} ${API}-clang++build_android# arm64 This instruction set supports a minimum of api21OUTPUT_FOLDER=arm64-v8aARCH=aarch64CPU=armv8-aTOOL_CPU_NAME=aarch64TOOL_PREFIX=$TOOLCHAIN/bin/$ {TOOL_CPU_NAME}-linux-androidOPTIMIZE_CFLAGS= "- march=$CPU" PREFIX=$ {PWD} / android/$OUTPUT_FOLDERCROSS_COMPILE=$TOOLCHAIN/bin/aarch64-linux-android-CC=$ {TOOL_PREFIX} ${API}-clangCXX=$ {TOOL_PREFIX} ${API}-clang++build_android# x86OTUTPUTOEFOLDERY x86ARCHY-86CPU-min x86TOOLY CPUBING i686TOOLPREFIXPREFIXY TOOLCHAING binder ${TOOL_CPU_NAME}-linux-androidOPTIMIZE_CFLAGS= "- march=i686- Mtune=intel-mssse3-mfpmath=sse-M32 "PREFIX=$ {PWD} / android/$OUTPUT_FOLDERCROSS_COMPILE=$TOOLCHAIN/bin/i686-linux-android-CC=$ {TOOL_PREFIX} ${API}-clangCXX=$ {TOOL_PREFIX} ${API}-clang++build_android# x86room64 This instruction set supports a minimum of api21OUTPUT_FOLDER=x86_64ARCH=x86_64CPU=x86-64 tooling CPUBING named names x86-64 TOOLING PREFIXPREFIXINTOOLCHAING ${TOOL_CPU_NAME}-linux-androidOPTIMIZE_CFLAGS= "- march=$CPU-mtune=intel-msse4.2-mpopcnt-M64" # output directory PREFIX=$ {PWD} / android/$OUTPUT_FOLDERCROSS_COMPILE=$TOOLCHAIN/bin/x86_64-linux-android-# so output directory,-- libdir=$LIB_DIR may not be specified # LIB_DIR= "${PWD} / android/libs/$OUTPUT_FOLDER" # compiler CC=$ {TOOL_PREFIX} ${API}-clangCXX=$ {TOOL_PREFIX} ${API}-clang++build_android is generated by default in the $PREFIX/lib directory

Modify file permissions

Chmod 777 build_android.sh

Execute build_android.sh

Can compile "armeabi-v7a", "arm64-v8a", "x86", "x86" 64

If the compilation fails, when you open the file to paste

: set ff # if you look at the file format, you will see fileformat=dos or fileformat=unix

: set ff=unix # set to unix format

: wq # Save exit

Compiled file

Take the .so library and put it in the Android project

Github lib library

Android_ffmpeg_lib

Taxiao213/android_ffmpeg_lib

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