build报错，找不到native层接口AMediaCodec

[DongJiyang]

如题，编译出错，内容如下：
undefined reference to `AMediaCodec_flush'
开始以为是头文件没包含，但是加了头文件后还是出错。

[DongJiyang]

已解决。

[oogh]

@DongJiyang 请问这个是怎么解决的？目前是在master分支上
运行时做了一点点的修改:

minSdkVersion = 21

另外尝试了把 CMakeLists.txt 中强制使用mediandk。但是仍然提示找不到AMediaCodec相关的引用。

错误信息如下：

Build command failed.
Error while executing process /Users/andy/Library/Android/sdk/cmake/3.6.4111459/bin/cmake with arguments {--build /Users/Workspace/xl_player/xl-player-armv7a/.externalNativeBuild/cmake/debug/armeabi-v7a --target xl_render}
[1/2] Building C object CMakeFiles/xl_render.dir/src/main/cpp/xl_decoders/xl_mediacodec.c.o
[2/2] Linking C shared library ../../../../build/intermediates/cmake/debug/obj/armeabi-v7a/libxl_render.so
        FAILED: : && /Users/andy/Library/Android/android-ndk-r14b/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang  --target=armv7-none-linux-androideabi --gcc-toolchain=/Users/andy/Library/Android/android-ndk-r14b/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64 --sysroot=/Users/andy/Library/Android/android-ndk-r14b/platforms/android-21/arch-arm -fPIC -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16 -fno-integrated-as -mthumb -Wa,--noexecstack -Wformat -Werror=format-security -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16 -fno-integrated-as -mthumb -Wa,--noexecstack -Wformat -Werror=format-security  -O0 -fno-limit-debug-info -O0 -fno-limit-debug-info  -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings -Wl,--fix-cortex-a8 -Wl,--exclude-libs,libunwind.a -L/Users/andy/Library/Android/android-ndk-r14b/sources/cxx-stl/llvm-libc++/libs/armeabi-v7a -Wl,--no-undefined -Wl,-z,noexecstack -Qunused-arguments -Wl,-z,relro -Wl,-z,now -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings -Wl,--fix-cortex-a8 -Wl,--exclude-libs,libunwind.a -L/Users/andy/Library/Android/android-ndk-r14b/sources/cxx-stl/llvm-libc++/libs/armeabi-v7a -Wl,--no-undefined -Wl,-z,noexecstack -Qunused-arguments -Wl,-z,relro -Wl,-z,now -shared -Wl,-soname,libxl_render.so -o ../../../../build/intermediates/cmake/debug/obj/armeabi-v7a/libxl_render.so CMakeFiles/xl_render.dir/src/main/cpp/xl_audio/xl_audio_player.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_audio/xl_audio_filter.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_container/xl_packet_queue.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_container/xl_packet_pool.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_container/xl_frame_queue.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_container/xl_frame_pool.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_decoders/xl_player_video_sw_decode_thread.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_decoders/xl_player_video_hw_decode_thread.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_decoders/xl_player_audio_decode_thread.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_decoders/xl_mediacodec.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_video/xl_tracker.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_video/xl_mat4.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_video/xl_model.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_video/xl_mesh_factory.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_video/xl_model_ball.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_video/xl_model_rect.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_video/xl_model_vr.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_video/xl_texture.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_video/xl_glsl_program.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_video/xl_video_render.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_video/xl_player_gl_thread.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_utils/xl_statistics.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_utils/xl_clock.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_utils/xl_jni_reflect.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_player.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_playerCore.c.o CMakeFiles/xl_render.dir/src/main/cpp/xl_player_read_thread.c.o  ../../../../build/intermediates/cmake/debug/obj/armeabi-v7a/libekf.so ../../../../ff_libs/armeabi-v7a/libavcodec-57.so ../../../../ff_libs/armeabi-v7a/libavformat-57.so ../../../../ff_libs/armeabi-v7a/libavutil-55.so ../../../../ff_libs/armeabi-v7a/libavfilter-6.so ../../../../ff_libs/armeabi-v7a/libswresample-2.so -llog -ljnigraphics -landroid -lEGL -lGLESv2 -lOpenSLES -lm && :
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:36: error: undefined reference to 'AMediaCodec_dequeueInputBuffer'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:40: error: undefined reference to 'AMediaCodec_getInputBuffer'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:43: error: undefined reference to 'AMediaCodec_queueInputBuffer'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:60: error: undefined reference to 'AMediaCodec_releaseOutputBuffer'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:67: error: undefined reference to 'AMediaCodec_dequeueOutputBuffer'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:80: error: undefined reference to 'AMediaCodec_getOutputFormat'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:81: error: undefined reference to 'AMediaFormat_getInt32'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:82: error: undefined reference to 'AMediaFormat_getInt32'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:83: error: undefined reference to 'AMediaFormat_getInt32'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:107: error: undefined reference to 'AMEDIAFORMAT_KEY_WIDTH'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:107: error: undefined reference to 'AMEDIAFORMAT_KEY_HEIGHT'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:107: error: undefined reference to 'AMEDIAFORMAT_KEY_COLOR_FORMAT'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:112: error: undefined reference to 'AMediaCodec_flush'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:122: error: undefined reference to 'AMediaFormat_new'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:132: error: undefined reference to 'AMediaCodec_createDecoderByType'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:133: error: undefined reference to 'AMediaFormat_setString'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:144: error: undefined reference to 'AMediaFormat_setBuffer'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:145: error: undefined reference to 'AMediaFormat_setBuffer'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:151: error: undefined reference to 'AMediaCodec_createDecoderByType'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:152: error: undefined reference to 'AMediaFormat_setString'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:163: error: undefined reference to 'AMediaFormat_setBuffer'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:168: error: undefined reference to 'AMediaCodec_createDecoderByType'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:169: error: undefined reference to 'AMediaFormat_setString'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:170: error: undefined reference to 'AMediaFormat_setBuffer'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:174: error: undefined reference to 'AMediaCodec_createDecoderByType'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:175: error: undefined reference to 'AMediaFormat_setString'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:191: error: undefined reference to 'AMediaFormat_setInt32'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:192: error: undefined reference to 'AMediaFormat_setInt32'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:195: error: undefined reference to 'AMEDIAFORMAT_KEY_MIME'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:195: error: undefined reference to 'AMEDIAFORMAT_KEY_MIME'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:195: error: undefined reference to 'AMEDIAFORMAT_KEY_MIME'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:195: error: undefined reference to 'AMEDIAFORMAT_KEY_MIME'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:195: error: undefined reference to 'AMEDIAFORMAT_KEY_WIDTH'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:195: error: undefined reference to 'AMEDIAFORMAT_KEY_HEIGHT'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:203: error: undefined reference to 'AMediaCodec_configure'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:207: error: undefined reference to 'AMediaCodec_start'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:214: error: undefined reference to 'AMediaCodec_stop'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:219: error: undefined reference to 'AMediaCodec_delete'
/Users/Workspace/xl_player/xl-player-armv7a/src/main/cpp/xl_decoders/xl_mediacodec.c:220: error: undefined reference to 'AMediaFormat_delete'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.

[oogh]

目的是想要学习下NdkMediaCodec的使用，但是修改为API21以后，编译就出现了上面的问题

[oogh]

(><)改错了...(><)，已解决

[miricaldad]

(><)改错了...(><)，已解决

你好最近在做这个开发，请问您那边有没有可以让我参考一下的工程呀

[StormGens]

请问是怎么解决的呀

[yanyi0]

请问如何解决的，error: undefined reference to 'AMediaFormat_new'

[DreamCloudWalker]

需要链接mediandk这个库，不然就会找不到。比如CMakeLists.txt里：
target_link_libraries( # Specifies the target library.
your-lib-name

    android
    mediandk
    ${log-lib})