ndk相关

1、ndk下载地址：https://developer.android.google.cn/ndk/downloads/older_releases.html

2、ndk编译ffmpeg脚本（版本太老，找替代中）

#!/bin/sh
NDK=/home/liuz4/WorkDir/Android/android-ndk-r10e
SYSROOT=$NDK/platforms/android-19/arch-arm
TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64
function build_one
{
./configure \
--prefix=$PREFIX \
--enable-shared \
--disable-static \
--disable-doc \
--disable-ffmpeg \
--disable-ffplay \
--disable-ffprobe \
--disable-avdevice \
--disable-doc \
--disable-symver \
--cross-prefix=$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

#!/bin/bash
make clean
export NDK=/usr/ndk/android-ndk-r10
e
export SYSROOT=$NDK/platforms/android-9/arch-arm/
export TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64
export CPU=arm
export PREFIX=$(pwd)/android/$CPU
export ADDI_CFLAGS="-marm"

./configure --target-os=linux \
--prefix=$PREFIX --arch=arm \
--disable-doc \
--enable-shared \
--disable-static \
--disable-yasm \
--disable-symver \
--enable-gpl \
--disable-ffmpeg \
--disable-ffplay \
--disable-ffprobe \
--disable-ffserver \
--disable-doc \
--disable-symver \
--cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
--enable-cross-compile \
--sysroot=$SYSROOT \
--extra-cflags="-Os -fpic $ADDI_CFLAGS" \
--extra-ldflags="$ADDI_LDFLAGS" \
$ADDITIONAL_CONFIGURE_FLAG
make clean
make
make install

3、Permission denied  说明该文件有权限问题（chmod 777 -R xxxxx）

4、Android studio报错:../../../../libs/x86_64/libswscale-3.so: incompatible target......ninja: build stopped: subcommand failed. 

解决办法：更换gradle的ndk{}

5、错误

Build command failed.
Error while executing process F:\LxDownloads\Android_Newest_SDK\cmake\3.6.4111459\bin\cmake.exe with arguments {--build F:\LxDownloads\WorkPlace\demo\ffmpeg_palyer\app\.externalNativeBuild\cmake\debug\arm64-v8a --target cpp}
[1/1] Linking CXX shared library F:\LxDownloads\WorkPlace\demo\ffmpeg_palyer\app\build\intermediates\cmake\debug\obj\arm64-v8a\libcpp.so
FAILED: cmd.exe /C "cd . && F:\LxDownloads\Android_Newest_SDK\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\clang++.exe  --target=aarch64-none-linux-android21 --gcc-toolchain=F:/LxDownloads/Android_Newest_SDK/ndk-bundle/toolchains/llvm/prebuilt/windows-x86_64 --sysroot=F:/LxDownloads/Android_Newest_SDK/ndk-bundle/toolchains/llvm/prebuilt/windows-x86_64/sysroot -fPIC -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -fno-addrsig -Wa,--noexecstack -Wformat -Werror=format-security -stdlib=libc++  -std=gnu++11 -O0 -fno-limit-debug-info  -Wl,--exclude-libs,libgcc.a -Wl,--exclude-libs,libatomic.a -static-libstdc++ -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings -Wl,--no-undefined -Qunused-arguments -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now -shared -Wl,-soname,libcpp.so -o F:\LxDownloads\WorkPlace\demo\ffmpeg_palyer\app\build\intermediates\cmake\debug\obj\arm64-v8a\libcpp.so CMakeFiles/cpp.dir/native-lib.cpp.o  ../../../../libs/arm64-v8a/libavcodec-56.so ../../../../libs/arm64-v8a/libavdevice-56.so ../../../../libs/arm64-v8a/libavfilter-5.so ../../../../libs/arm64-v8a/libavformat-56.so ../../../../libs/arm64-v8a/libavutil-54.so ../../../../libs/arm64-v8a/libpostproc-53.so ../../../../libs/arm64-v8a/libswresample-1.so ../../../../libs/arm64-v8a/libswscale-3.so -llog -latomic -lm && cd ."
../../../../libs/arm64-v8a/libavcodec-56.so: error adding symbols: File in wrong format

clang++.exe: error: linker command failed with exit code 1 (use -v to see invocation)

ninja: build stopped: subcommand failed.

解决办法：1、更换linux生成so时的ndk版本10e->17 (更换地址：@1、ndk下载地址)       解决结果：失败（可能是‘arm64-v8a’，不是‘armeabi-v7a’的原因）

                 2、更换linux生成so时的ndk版本17->Android studio对应的ndk ，并且设置gradle ndk版本为

                       ndk { abiFilters 'armeabi-v7a'},sh的设置:

                        解决结果：运行成功！！【鲜花】

                 3、基于2修改.sh文件解决结果：编译通过。【掌声】

6、错误:能正常运行，但是启动app出现

    java.lang.UnsatisfiedLinkError: dalvik.system.PathClassLoader[DexPathList[[zip file "/data/app/com.example.smallwalnut.ffmpeg_palyer-NqwfgamE0UmWI3W0R8FRLA==/base.apk"],nativeLibraryDirectories=[/data/app/com.example.smallwalnut.ffmpeg_palyer-NqwfgamE0UmWI3W0R8FRLA==/lib/arm, /data/app/com.example.smallwalnut.ffmpeg_palyer-NqwfgamE0UmWI3W0R8FRLA==/base.apk!/lib/armeabi-v7a, /system/lib, /system/vendor/lib]]] couldn't find "liblibavcodec.so"

原因：       CMakeLists.txt命名错误，如下所示：

add_library( libavcodec
        SHARED
        IMPORTED )
set_target_properties( libavcodec
        PROPERTIES IMPORTED_LOCATION
        ${distribution_DIR}/${ANDROID_ABI}/libavcodec.so)

解决方式：libavcodec.so应该命名为 avcodec（系统会默认加上lib）

add_library( avcodec
        SHARED
        IMPORTED )
set_target_properties( avcodec
        PROPERTIES IMPORTED_LOCATION
        ${distribution_DIR}/${ANDROID_ABI}/libavcodec.so)

7、undefined reference to "av_register_all"

#include "include/libavcodec/avcodec.h"
#include "include/libavformat/avformat.h"
#include "include/libswscale/swscale.h"
#include "include/libavutil/avutil.h"
#include "include/libavutil/frame.h"


报错：
undefined reference to "av_register_all"

解决 ： 

extern "C" {
#include "include/libavcodec/avcodec.h"
#include "include/libavformat/avformat.h"
#include "include/libswscale/swscale.h"
#include "include/libavutil/avutil.h"
#include "include/libavutil/frame.h"
}