Clang compile link ffmpeg FAQ

One 、 Problems encountered during compilation

1、 Command not found

error message ：

./build_android.sh: line 18: --enable-shared: command not found ./build_android.sh: line 20: --disable-static: command not found ./build_android.sh: line 22: --disable-doc: command not found ./build_android.sh: line 24: --disable-ffmpeg: command not found ./build_android.sh: line 26: --disable-ffplay: command not found ./build_android.sh: line 28: --disable-ffprobe: command not found ./build_android.sh: line 30: --disable-ffserver: command not found ./build_android.sh: line 32: --disable-avdevice: command not found

solve ：
If it's direct copy Online shell Script , It could be dos Format , Please use dos2unix build_android.sh Change my , Delete the extra space ( This is very important dos2unix It's a tool , If not, please install it first ：brew install dos2unix , It'll be over soon .

2、xmakefile File not generated

error message ：

./android_config.sh: line 36: --enable-shared: command not found Makefile:2: ffbuild/config.mak: No such file or directory Makefile:40: /tools/Makefile: No such file or directory Makefile:41: /ffbuild/common.mak: No such file or directory Makefile:91: /libavutil/Makefile: No such file or directory Makefile:91: /ffbuild/library.mak: No such file or directory Makefile:93: /fftools/Makefile: No such file or directory Makefile:94: /doc/Makefile: No such file or directory Makefile:95: /doc/examples/Makefile: No such file or directory Makefile:160: /tests/Makefile: No such file or directory make: *** No rule to make target `/tests/Makefile'. Stop. Makefile:2: ffbuild/config.mak: No such file or directory Makefile:40: /tools/Makefile: No such file or directory Makefile:41: /ffbuild/common.mak: No such file or directory Makefile:91: /libavutil/Makefile: No such file or directory Makefile:91: /ffbuild/library.mak: No such file or directory Makefile:93: /fftools/Makefile: No such file or directory Makefile:94: /doc/Makefile: No such file or directory Makefile:95: /doc/examples/Makefile: No such file or directory Makefile:160: /tests/Makefile: No such file or directory

solve ：
perform ./configure --disable-x86asm  Generate config.mak file

3、arm-linux-androideabi-gcc is unable to create an executable file

error message ：

/Users/aria/dev/android/sdk/ndk-bundle/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-gcc is unable to create an executable file.

reason ：
Check ndk edition ,android The official from r18b Start , Has been removed gcc See ndk r18b Revised content
solve ：
Use clang Compile , For details, see ：https://medium.com/@ilja.kosynkin/building-ffmpeg-4-0-for-android-with-clang-642e4911c31e

4、/android_config.sh:line32:xxxx No such file or directory

reason ：
.configure The following commands cannot have comments

solve ：
Which line of code to delete the comment

5、static declaration of 'xxx' follows non-static declaration

solve ：
config.h Search for lrint、lrintf、round、roundf Wait for the right character , take 0 It is amended as follows 1

#define HAVE_LLRINT 1 #define HAVE_LLRINTF 1 #define HAVE_LRINT 1 #define HAVE_LRINTF 1 #define HAVE_ROUND 1 #define HAVE_ROUNDF 1 #define HAVE_CBRT 1 #define HAVE_CBRTF 1 #define HAVE_COPYSIGN 1 #define HAVE_TRUNC 1 #define HAVE_TRUNCF 1 #define HAVE_RINT 1 #define HAVE_HYPOT 1 #define HAVE_ERF 1

Or use it directly sed To modify the config.h file

sed -i -e 's/#define HAVE_LLRINT 0/#define HAVE_LLRINT 1/g' config.h sed -i -e 's/#define HAVE_LLRINTF 0/#define HAVE_LLRINTF 1/g' config.h sed -i -e 's/#define HAVE_LRINT 0/#define HAVE_LRINT 1/g' config.h sed -i -e 's/#define HAVE_LRINTF 0/#define HAVE_LRINTF 1/g' config.h sed -i -e 's/#define HAVE_ROUND 0/#define HAVE_ROUND 1/g' config.h sed -i -e 's/#define HAVE_ROUNDF 0/#define HAVE_ROUNDF 1/g' config.h sed -i -e 's/#define HAVE_CBRT 0/#define HAVE_CBRT 1/g' config.h sed -i -e 's/#define HAVE_CBRTF 0/#define HAVE_CBRTF 1/g' config.h sed -i -e 's/#define HAVE_COPYSIGN 0/#define HAVE_COPYSIGN 1/g' config.h sed -i -e 's/#define HAVE_TRUNC 0/#define HAVE_TRUNC 1/g' config.h sed -i -e 's/#define HAVE_TRUNCF 0/#define HAVE_TRUNCF 1/g' config.h sed -i -e 's/#define HAVE_RINT 0/#define HAVE_RINT 1/g' config.h sed -i -e 's/#define HAVE_HYPOT 0/#define HAVE_HYPOT 1/g' config.h sed -i -e 's/#define HAVE_ERF 0/#define HAVE_ERF 1/g' config.h sed -i -e 's/#define HAVE_GMTIME_R 0/#define HAVE_GMTIME_R 1/g' config.h sed -i -e 's/#define HAVE_LOCALTIME_R 0/#define HAVE_LOCALTIME_R 1/g' config.h sed -i -e 's/#define HAVE_INET_ATON 0/#define HAVE_INET_ATON 1/g' config.h

6、xxxx error:expected ')'

error message ：

#define getenv(x) NULL ^ /home/cd008/diska/android-ndk-r9/platforms/android-18/arch-arm/usr/include/stdlib.h:54:14: note: in expansion of macro 'getenv' extern char *getenv(const char *); ^ ./config.h:17:19: error: expected ')' before numeric constant #define getenv(x) NULL ^ /home/cd008/diska/android-ndk-r9/platforms/android-18/arch-arm/usr/include/stdlib.h:54:14: note: in expansion of macro 'getenv' extern char *getenv(const char *);

solve ：
stay config.h Note out #define getenv(x) NULL
/#define getenv(x) NULL/

sed -i -e 's/#define getenv(x) NULL/\/\*#define getenv(x) NULL\*\//g' config.h

7、arm-linux-androideabi-ld -Wl,-soname,libavutil.so unknown option

error message ：

Users/aria/dev/android/sdk/ndk-bundle/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-ld -Wl,-soname

reason ：
gcc structure  .so  The order is  -shared -wl,soname,xxxx.so  and clang Yes.  -shared -soname xxx.so

solve ：
modify ffbuild/config.mak file , take SHFLAGS=-shared -Wl,-soname,$(SLIBNAME) It is amended as follows SHFLAGS=-shared -soname $(SLIBNAME)

8、arm-linux-androideabi-ld:fatal error:-shared and -pie are incompatible

solve ：
modify ffbuild/config.mak file , take LDEXEFLAGS= -fPIE -pie  Get rid of -pie

9、member at 2760 is not an ELF object

reason 1： Not used ndk Band ar To pack
solve ： Check ar Whether the path of the command is correct
reason 2: macos ranlib and ndk Of ranlib Are not compatible
solve ： see 3.8

10、the table of contents is empty(no object file memberss in the library define global symbols)

reason ：
macos Of ranlib and ndk Of ranlib Are not compatible
solve ：
Use ndk Self contained ranlib

ranlib=xxxx/arm-linux-androideabi-runlib

11、undefined reference to '__aeabi_memcpy'

reason ：
ld Merge multiple .a Static library parameter error
solve ：
take -static Change it to -shared

12、undefined reference xxxx

reason ：
ffmpeg Problems caused by inlining
solve ：
There is no effective solution for the time being

summary

The most common problem in the compilation process is clang、ld、ar And other tools , When these errors occur , Various tools should be used --help To check if the configuration is correct , Especially from gcc Over to clang,gcc and clang Many configurations of are different , Most tutorials on the Internet use gcc To compile the ffmpeg.

clang --help xxxxxx-ld --help xxxxxx-ar --help

Two 、 Problems encountered in link execution

FFmepeg Problems encountered in compiling execution files and solutions _Croxd The blog of -CSDN Blog _ffmepeg problem 1：/home/xy/ffmpeg/ffmpeg-4.1.3_1/out/lib//libswscale.a(utils.o)： In function ‘handle_formats’ in ：utils.c:(.text+0x238)： Yes ‘pow’ Undefined references utils.c:(.text+0x248)： Yes ‘lrint’ Undefined reference problem 1 resolvent ： Add at compile time ：-lm problem 2：/home/xy...https://blog.csdn.net/weixin_42432281/article/details/95330986