Android接入ffmpeg库及问题解决方法
作者:lorienzhang
一、准备交叉编译环境
我的环境如下:
- 系统:ubuntu20.04
- NDK版本:r17c
参考教程及NDK构建交叉工具链:https://www.jb51.net/article/92161.htm
下载之后解压,我的NDK解压路径为:/work/android/sdk/ndk/android-ndk-r17c/
安装独立工具链需要安装python,如果没有,安装下:
lorien@ubuntu-20: sudo apt-get install python
然后执行工具链构建脚本:
lorien@ubuntu-20: cd /work/android/sdk/ndk/android-ndk-r17c/build/tools/ lorien@ubuntu-20: ./make_standalone_toolchain.py \ --arch arm64 \ --api 21 \ --install-dir /work/tmp/android-toolchain
–install-dir参数指定了交叉工具链的路径,进入该目录看下:
lorien@ubuntu-20: cd /work/tmp/android-toolchain/ lorien@ubuntu-20: ls aarch64-linux-android COPYING COPYING.LIB lib manifest_4691093.xml MODULE_LICENSE_MIT repo.prop test AndroidVersion.txt COPYING3 COPYING.RUNTIME lib64 MODULE_LICENSE_BSD_LIKE NOTICE share bin COPYING3.LIB include libexec MODULE_LICENSE_GPL prebuilt_include sysroot
几个比较重要的目录:
- bin目录:里面是编译、链接可执行工具
- sysroot:里面是基础库的头文件和lib
二、交叉编译ffmpeg+libx264+libfdk-aac
1. 交叉编译libfdk-aac
下载libfdk-aac源码:https://sourceforge.net/projects/opencore-amr/files/fdk-aac/
编写配置configure脚本config-arm64.sh,将文件放入libfdk-aac源码跟目录中,脚本内容如下:
#!/bin/bash export PATH=$PATH:/work/tmp/android-toolchain/bin SYSROOT=/work/tmp/android-toolchain/sysroot target_host=aarch64-linux-android export AR=$target_host-ar export AS=$target_host-clang export CC=$target_host-clang export CXX=$target_host-clang++ export LD=$target_host-ld export STRIP=$target_host-strip export RANLIB=$target_host-ranlib # 注意要加-D__ANDROID_API__选项,否则可能会遇到undefined reference to 'stderr'错误 export CFLAGS="-fPIC -D__ANDROID_API__=21 -I$SYSROOT/usr/include" export CPPFLAGS="-fPIC -D__ANDROID_API__=21 -I$SYSROOT/usr/include" export CXXFLAGS="-fPIC -D__ANDROID_API__=21 -I$SYSROOT/usr/include" export LDFLAGS="-L$SYSROOT/usr/lib" ./configure --host=aarch64-linux-android \ --enable-static \ --disable-shared \ --prefix=$(pwd)/install/
执行脚本:
lorien@ubuntu-20: cd /work/android/media/fdk-aac-2.0.2/ lorien@ubuntu-20: ./config-arm64.sh
可能会报错:
/work/tmp/android-toolchain/bin/clang60: error while loading shared libraries: libtinfo.so.5: cannot open shared object file: No such file or directory
是缺少 libtinfo5导致的,需要安装下:
lorien@ubuntu-20: sudo apt-get install libtinfo5
再重新执行config-arm64.sh脚本,即可配置成功。
接下来,编译安装
lorien@ubuntu-20: make lorien@ubuntu-20: make install
编译期间可能会碰到一些错误:
错误1:
libSBRdec/src/lpp_tran.cpp:122:10: fatal error: ‘log/log.h’ file not found
解决:
删除代码 include “log/log.h”
错误2:
libSBRdec/src/lpp_tran.cpp:341:5: error: use of undeclared identifier ‘android_errorWriteLog’
解决:
删除调用代码即可
错误处理后再重新编译&安装,成功后进入/work/android/media/fdk-aac-2.0.2/install 目录下可看到编译产物:
lorien@ubuntu-20: cd install/ include lib
include目录下是产生头文件,lib目录下是一些.a的库文件。
2. 交叉编译libx264
下载libx264源码:git clone https://code.videolan.org/videolan/x264.git
和上面类似,进入x264源码根目录,编写config脚本config-arm64.sh:
#!/bin/bash export PATH=$PATH:/work/tmp/android-toolchain/bin SYSROOT=/work/tmp/android-toolchain/sysroot target_host=aarch64-linux-android export CFLAGS="-fPIC -D__ANDROID_API__=21 -I$SYSROOT/usr/include" export CPPFLAGS="-fPIC -D__ANDROID_API__=21 -I$SYSROOT/usr/include" export CXXFLAGS="-fPIC -D__ANDROID_API__=21 -I$SYSROOT/usr/include" export LDFLAGS="-L$SYSROOT/usr/lib" ./configure --host=aarch64-linux-android \ --cross-prefix=$target_host- \ --sysroot=$SYSROOT \ --enable-static \ --enable-shared \ --prefix=$(pwd)/install/
执行脚本,然后make&make install即可。根据-prefix选项配置,编译产物会输出到 /work/android/media/x264/install目录下面。
3. 交叉编译ffmpeg
fdk-aac和x264编译完成之后,我们可以编译ffmpeg了,ffmpeg会使用上面编译出来的两个库。
首先,下载ffmpeg源码:
lorien@ubuntu-20: git clone https://git.ffmpeg.org/ffmpeg.git ffmpeg
进入ffmpeg源码根目录,编写配置脚本config-arm64.sh:
#!/bin/bash export PATH=$PATH:/work/tmp/android-toolchain/bin SYSROOT=/work/tmp/android-toolchain/sysroot target_host=aarch64-linux-android export CFLAGS="-fPIC -D__ANDROID_API__=21 -I$SYSROOT/usr/include -I$(pwd)/../fdk-aac-2.0.2/install/include -I$(pwd)/../x264/install/include" export LDFLAGS="-L$SYSROOT/usr/lib -L$(pwd)/../fdk-aac-2.0.2/install/lib -L$(pwd)/../x264/install/lib" ./configure --cross-prefix=$target_host- \ --enable-cross-compile \ --sysroot=$SYSROOT \ --arch=aarch64 \ --target-os=linux \ --enable-static \ --disable-shared \ --enable-gpl \ --enable-nonfree \ --disable-ffmpeg \ --disable-ffplay \ --disable-ffprobe \ --disable-doc \ --disable-devices \ --disable-avdevice \ --disable-postproc \ --disable-avfilter \ --disable-filters \ --disable-protocols \ --enable-libx264 \ --enable-libfdk-aac \ --prefix=$(pwd)/install/
在配置ffmpeg时,添加*–enable-libx264选项和–enable-libfdk-aac* 即可使ffmpeg打开x264和fdk-aac。需要注意的是,我们要在CFLAGS编译选项中添加*-I参数来指明ffmpeg编译x264和fdk-aac库使用两个外部库的头文件目录,以及通过-L* 选项指明ffmpeg在链接外部库时库文件目录。
配置完之后,我们通过make & make install进行编译安装。
编译可能遇到错误:
错误一:
libavcodec/aaccoder.c: In function 'search_for_ms':
libavcodec/aaccoder.c:803:25: error: expected identifier or '(' before numeric constant
int B0 = 0, B1 = 0;
^
libavcodec/aaccoder.c:865:28: error: lvalue required as left operand of assignment
B0 += b1+b2;
^
libavcodec/aaccoder.c:866:25: error: 'B1' undeclared (first use in this function)
B1 += b3+b4;
libavcodec/aaccoder.c:866:25: note: each undeclared identifier is reported only once for each function it appears in
make: *** [libavcodec/aaccoder.o] Error 1
解决:将libavcodec/aaccoder.c文件B0变量替换成b0
错误二:
libavcodec/hevc_mvs.c: In function 'derive_spatial_merge_candidates':
libavcodec/hevc_mvs.c:208:15: error: 'y0000000' undeclared (first use in this function)
((y ## v) >> s->ps.sps->log2_min_pu_size))
^
libavcodec/hevc_mvs.c:204:14: note: in definition of macro 'TAB_MVF'
tab_mvf[(y) * min_pu_width + x]
^
libavcodec/hevc_mvs.c:274:16: note: in expansion of macro 'TAB_MVF_PU'
(cand && !(TAB_MVF_PU(v).pred_flag == PF_INTRA))
^
libavcodec/hevc_mvs.c:368:23: note: in expansion of macro 'AVAILABLE'
is_available_b0 = AVAILABLE(cand_up_right, B0) &&
^
libavcodec/hevc_mvs.c:208:15: note: each undeclared identifier is reported only once for each function it appears in
解决: 将libavcodec/hevc_mvs.c文件的变量B0改成b0,xB0改成xb0,yB0改成yb0
错误三:
libavcodec/opus_pvq.c: In function ‘quant_band_template’:
libavcodec/opus_pvq.c:498:9: error: expected identifier or ‘(’ before
numeric constant
int B0 = blocks;
^ libavcodec/opus_pvq.c:559:12: error: lvalue required as left operand of assignment
B0 = blocks;
^ make: *** [libavcodec/opus_pvq.o] Error 1
解决:将libavcodec/opus_pvq.c文件的变量B0改成b0
解完所有错误后,重新编译、安装。看下编译产物
lorien@ubuntu-20: cd /work/android/media/ffmpeg/install/ lorien@ubuntu-20: ls include lib share lorien@ubuntu-20: cd lib lorien@ubuntu-20: ls libavcodec.a libavformat.a libavutil.a libswresample.a libswscale.a pkgconfig
可以看到在lib下有一系列静态库文件。.a文件有点多,下面我们将所有.a文件打包一个so文件,方便后面引入,打包脚本如下:
#!/bin/bash export PATH=$PATH:/work/tmp/android-toolchain/bin SYSROOT=/work/tmp/android-toolchain/sysroot aarch64-linux-android-ld -rpath-link=-L$SYSROOT/usr/lib \ -L$SYSROOT/usr/lib \ -L$(pwd)/x264 \ -lc -lm -lz -ldl -lx264 \ -soname libffmpeg.so \ -shared \ -nostdlib \ -Bsymbolic \ --whole-archive \ --no-undefined \ -o libffmpeg.so \ libavcodec.a libavformat.a libavutil.a libswresample.a libswscale.a \ $(pwd)/fdk-aac/libfdk-aac.a \ $SYSROOT/../lib/gcc/aarch64-linux-android/4.9.x/libgcc.a
通过ld命令,将所有.a文件打包成libffmpeg.so文件。接下来再用strip命令优化下so
lorien@ubuntu-20: aarch64-linux-android-strip libffmpeg.so
至此,libffmpeg.so库文件就已经制作好了。
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