如何使用 libx265 为 Android 编译 FFmpeg？
How to compile FFmpeg with libx265 for Android?
我已经为 Android 成功编译了带有 libx264（作为静态库）的 FFmpeg。但我也想在 Android 上的 FFmpeg 中使用 libx265（作为静态库）。所以我做了一些尝试：
首先，我修复了libx265的log2 function和posix_memalign function not found问题，将它们改为log（使用log来近似log2）函数和memalign（替换posix_memalign并做一些调整）功能。并通过删除 cmakelist.txt 文件中的“-lpthread”修复了 pthread 链接问题。
然后，我使用 cmake 和 make 成功编译了 libx265（作为静态库）。
我在配置 FFmpeg 时启用了 libx265。但是当配置运行时，它在屏幕上显示"libx265 not found using pkg-config"。
我检查了 config.log，发现了这些错误信息：
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(bitstream.cpp.o):bitstream.cpp:typeinfo for x265::BitInterface: error: undefined reference to 'vtable for __cxxabiv1::__class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(bitstream.cpp.o):bitstream.cpp:typeinfo for x265::Bitstream: error: undefined reference to 'vtable for __cxxabiv1::__si_class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(encoder.cpp.o):encoder.cpp:typeinfo for x265::SEIDecodedPictureHash: error: undefined reference to 'vtable for __cxxabiv1::__si_class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(encoder.cpp.o):encoder.cpp:typeinfo for x265::SEIuserDataUnregistered: error: undefined reference to 'vtable for __cxxabiv1::__si_class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(encoder.cpp.o):encoder.cpp:typeinfo for x265::SEIMasteringDisplayColorVolume: error: undefined reference to 'vtable for __cxxabiv1::__si_class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(threading.cpp.o):threading.cpp:typeinfo for x265::Thread: error: undefined reference to 'vtable for __cxxabiv1::__class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(wavefront.cpp.o):wavefront.cpp:typeinfo for x265::JobProvider: error: undefined reference to 'vtable for __cxxabiv1::__class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(slicetype.cpp.o):slicetype.cpp:typeinfo for x265::BondedTaskGroup: error: undefined reference to 'vtable for __cxxabiv1::__class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(frameencoder.cpp.o):frameencoder.cpp:function x265::FrameEncoder::encodeSlice(): error: undefined reference to '__dynamic_cast'
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(frameencoder.cpp.o):frameencoder.cpp:function x265::FrameEncoder::encodeSlice(): error: undefined reference to '__dynamic_cast'
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(frameencoder.cpp.o):frameencoder.cpp:function x265::FrameEncoder::processRowEncoder(int, x265::ThreadLocalData&): error: undefined reference to '__dynamic_cast'
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(frameencoder.cpp.o):frameencoder.cpp:function .LTHUNK2: error: undefined reference to '__dynamic_cast'
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(frameencoder.cpp.o):frameencoder.cpp:typeinfo for x265::FrameEncoder: error: undefined reference to 'vtable for __cxxabiv1::__vmi_class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(sei.cpp.o):sei.cpp:typeinfo for x265::SEI: error: undefined reference to 'vtable for __cxxabiv1::__vmi_class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
我该如何解决？
我找到了解决方案。
我需要手动添加「libgnustl_static.a」的路径到gcc/g++作为参数。这样就编译成功了
最近刚遇到这个错误，和user3032481说的一样。
我修改ffmpeg的配置如下。
--extra-libs="-lother_libs -L/Users/shutup/Library/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/libs/armeabi -lgnustl_static" \
我认为，原因是 x265 需要 c++ rtti 功能，但 android 默认 libstdc++ 不包含它。所以我们需要添加 libgnustl_static.a .
我已经为 Android 成功编译了带有 libx264（作为静态库）的 FFmpeg。但我也想在 Android 上的 FFmpeg 中使用 libx265（作为静态库）。所以我做了一些尝试：
首先，我修复了libx265的log2 function和posix_memalign function not found问题，将它们改为log（使用log来近似log2）函数和memalign（替换posix_memalign并做一些调整）功能。并通过删除 cmakelist.txt 文件中的“-lpthread”修复了 pthread 链接问题。
然后，我使用 cmake 和 make 成功编译了 libx265（作为静态库）。
我在配置 FFmpeg 时启用了 libx265。但是当配置运行时，它在屏幕上显示"libx265 not found using pkg-config"。
我检查了 config.log，发现了这些错误信息：
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(bitstream.cpp.o):bitstream.cpp:typeinfo for x265::BitInterface: error: undefined reference to 'vtable for __cxxabiv1::__class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(bitstream.cpp.o):bitstream.cpp:typeinfo for x265::Bitstream: error: undefined reference to 'vtable for __cxxabiv1::__si_class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(encoder.cpp.o):encoder.cpp:typeinfo for x265::SEIDecodedPictureHash: error: undefined reference to 'vtable for __cxxabiv1::__si_class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(encoder.cpp.o):encoder.cpp:typeinfo for x265::SEIuserDataUnregistered: error: undefined reference to 'vtable for __cxxabiv1::__si_class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(encoder.cpp.o):encoder.cpp:typeinfo for x265::SEIMasteringDisplayColorVolume: error: undefined reference to 'vtable for __cxxabiv1::__si_class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(threading.cpp.o):threading.cpp:typeinfo for x265::Thread: error: undefined reference to 'vtable for __cxxabiv1::__class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(wavefront.cpp.o):wavefront.cpp:typeinfo for x265::JobProvider: error: undefined reference to 'vtable for __cxxabiv1::__class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(slicetype.cpp.o):slicetype.cpp:typeinfo for x265::BondedTaskGroup: error: undefined reference to 'vtable for __cxxabiv1::__class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(frameencoder.cpp.o):frameencoder.cpp:function x265::FrameEncoder::encodeSlice(): error: undefined reference to '__dynamic_cast'
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(frameencoder.cpp.o):frameencoder.cpp:function x265::FrameEncoder::encodeSlice(): error: undefined reference to '__dynamic_cast'
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(frameencoder.cpp.o):frameencoder.cpp:function x265::FrameEncoder::processRowEncoder(int, x265::ThreadLocalData&): error: undefined reference to '__dynamic_cast'
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(frameencoder.cpp.o):frameencoder.cpp:function .LTHUNK2: error: undefined reference to '__dynamic_cast'
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(frameencoder.cpp.o):frameencoder.cpp:typeinfo for x265::FrameEncoder: error: undefined reference to 'vtable for __cxxabiv1::__vmi_class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
/home/user/ffmpeg-2.8.1/android/arm/lib/libx265.a(sei.cpp.o):sei.cpp:typeinfo for x265::SEI: error: undefined reference to 'vtable for __cxxabiv1::__vmi_class_type_info'
/home/user/ffmpeg-2.8.1/android/arm/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
我该如何解决？
我找到了解决方案。
我需要手动添加「libgnustl_static.a」的路径到gcc/g++作为参数。这样就编译成功了
最近刚遇到这个错误，和user3032481说的一样。
我修改ffmpeg的配置如下。
--extra-libs="-lother_libs -L/Users/shutup/Library/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/libs/armeabi -lgnustl_static" \
我认为，原因是 x265 需要 c++ rtti 功能，但 android 默认 libstdc++ 不包含它。所以我们需要添加 libgnustl_static.a .