编译ffmpeg无法生成ffplay的问题解决

转自：http://blog.chinaunix.net/uid-11344913-id-3936227.html

编译ffmpeg无法生成ffplay的问题解决

好多人问编译ffmpeg时无法生成ffplay，其具体原因多数是由于没有SDL或者SDL版本不正确所导致。

解决办法如下:

安装正确的SDL库既可解决

点击(此处)折叠或打开

wget http://libsdl.org/release/SDL-1.2.15.tar.gz
tar zxvf SDL-1.2.15.tar.gz

cd SDL-1.2.15

./configure --prefix=/usr

make -j16

sudo make install

安装完成后，再次编译ffmpeg既可解决

原因分析：

打开configure分析一下内容既可看到如下内容：

点击(此处)折叠或打开

SDL_CONFIG="${cross_prefix}sdl-config"

if check_pkg_config sdl SDL_events.h SDL_PollEvent; then 

    check_cpp_condition SDL.h "(SDL_MAJOR_VERSION<<16 | SDL_MINOR_VERSION<<8
| SDL_PATCHLEVEL) >= 0x010201" $sdl_cflags &&

    check_cpp_condition SDL.h "(SDL_MAJOR_VERSION<<16 | SDL_MINOR_VERSION<<8
| SDL_PATCHLEVEL) < 0x010300" $sdl_cflags &&

    enable sdl

else

  if "${SDL_CONFIG}" --version > /dev/null
2>&1; then 

    sdl_cflags=$("${SDL_CONFIG}" --cflags)

    sdl_libs=$("${SDL_CONFIG}" --libs)

    check_func_headers SDL_version.h SDL_Linked_Version $sdl_cflags $sdl_libs &&

    check_cpp_condition SDL.h "(SDL_MAJOR_VERSION<<16 | SDL_MINOR_VERSION<<8
| SDL_PATCHLEVEL) >= 0x010201" $sdl_cflags &&

    check_cpp_condition SDL.h "(SDL_MAJOR_VERSION<<16 | SDL_MINOR_VERSION<<8
| SDL_PATCHLEVEL) < 0x010300" $sdl_cflags &&

    enable sdl

  fi

fi

enabled sdl && add_cflags $sdl_cflags && add_extralibs
$sdl_libs

这里比较关键，首先判断SDL.h中的版本对应的值在通过计算后是否在0x010201至0x010300之间，如果是的话SDL版本才会正确的被执行，否则这个测试项将会出现错误，生成的config.log中有对应的错误记录

当没有安装SDL库时，config.log中相关的错误信息如下

点击(此处)折叠或打开

check_pkg_config sdl SDL_events.h SDL_PollEvent

false --exists --print-errors
sdl

当安装的SDL版本库不对应时，config.log中对应的错误信息如下

点击(此处)折叠或打开

check_pkg_config sdl SDL_events.h SDL_PollEvent

false --exists --print-errors
sdl

check_func_headers SDL_version.h SDL_Linked_Version -I/usr/include/SDL2 -I/usr/X11R6/include -D_THREAD_SAFE -L/usr/lib -lSDL2

check_ld cc -I/usr/include/SDL2 -I/usr/X11R6/include -D_THREAD_SAFE -L/usr/lib -lSDL2

check_cc -I/usr/include/SDL2 -I/usr/X11R6/include -D_THREAD_SAFE -L/usr/lib

BEGIN /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.NYPJoPCV.c

    1 #include <SDL_version.h>

    2 long check_SDL_Linked_Version(void) { return (long) SDL_Linked_Version; }

    3 int main(void) { return 0; } 

bbs.chinaffmpeg.com 孙悟空

END /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.NYPJoPCV.c

gcc -D_ISOC99_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -DPIC -std=c99 -mdynamic-no-pic -fomit-frame-pointer -fPIC -I/usr/include/SDL2 -I/usr/X11R6/include -D_THREAD_SAFE -L/usr/lib -c -o /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.q6QhmvUN.o /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.NYPJoPCV.c

/var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.NYPJoPCV.c: In
function 'check_SDL_Linked_Version':

/var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.NYPJoPCV.c:2: error: 'SDL_Linked_Version' undeclared (first
use in this function)

/var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.NYPJoPCV.c:2: error: (Each
undeclared identifier is reported only once 

/var/folders/z5/31tj_ff9
10e32
77n3r59bx1cwg98c0000gn/T//ffconf.NYPJoPCV.c:2: error: for each
function it appears in.)

或者如下错误

点击(此处)折叠或打开

BEGIN /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.mfC1B2mW.c

    1 #include <SDL_version.h>

    2 long check_SDL_GetVersion(void) { return (long) SDL_GetVersion; }

    3 int main(void) { return 0; } 

END /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.mfC1B2mW.c

gcc -D_ISOC99_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -DPIC -std=c99 -mdynamic-no-pic -fomit-frame-pointer -fPIC -I/usr/local/include/SDL2 -I/usr/X11R6/include -D_THREAD_SAFE -L/usr/local/lib -c -o /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.E9d2cGZ6.o /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.mfC1B2mW.c

gcc -Wl,-dynamic,-search_paths_first -I/usr/local/include/SDL2 -I/usr/X11R6/include -D_THREAD_SAFE -L/usr/local/lib -o /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.Z74XFGa5 /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.E9d2cGZ6.o -lSDL2 -lm -lbz2 -lz

check_cpp_condition SDL.h (SDL_MAJOR_VERSION<<16 | SDL_MINOR_VERSION<<8 | SDL_PATCHLEVEL) >= 0x010201 -I/usr/local/include/SDL2 -I/usr/X11R6/include -D_THREAD_SAFE

check_cpp -I/usr/local/include/SDL2 -I/usr/X11R6/include -D_THREAD_SAFE

BEGIN /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.mfC1B2mW.c

    1 #include <SDL.h>

    2 #if !((SDL_MAJOR_VERSION<<16 | SDL_MINOR_VERSION<<8 | SDL_PATCHLEVEL) >= 0x010201)

    3 #error "unsatisfied condition: (SDL_MAJOR_VERSION<<16 | SDL_MINOR_VERSION<<8 | SDL_PATCHLEVEL) >= 0x010201"

    4 #endif

END /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.mfC1B2mW.c

gcc -D_ISOC99_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -DPIC -std=c99 -mdynamic-no-pic -fomit-frame-pointer -fPIC -I/usr/local/include/SDL2 -I/usr/X11R6/include -D_THREAD_SAFE -E -o /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.E9d2cGZ6.o /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.mfC1B2mW.c

check_cpp_condition SDL.h (SDL_MAJOR_VERSION<<16 | SDL_MINOR_VERSION<<8 | SDL_PATCHLEVEL) < 0x010300 -I/usr/local/include/SDL2 -I/usr/X11R6/include -D_THREAD_SAFE

check_cpp -I/usr/local/include/SDL2 -I/usr/X11R6/include -D_THREAD_SAFE

BEGIN /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.mfC1B2mW.c

    1 #include <SDL.h>

    2 #if !((SDL_MAJOR_VERSION<<16 | SDL_MINOR_VERSION<<8 | SDL_PATCHLEVEL) < 0x010300)

    3 #error "unsatisfied condition: (SDL_MAJOR_VERSION<<16 | SDL_MINOR_VERSION<<8 | SDL_PATCHLEVEL) < 0x010300"

    4 #endif

bbs.chinaffmpeg.com 孙悟空

END /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.mfC1B2mW.c

gcc -D_ISOC99_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -DPIC -std=c99 -mdynamic-no-pic -fomit-frame-pointer -fPIC -I/usr/local/include/SDL2 -I/usr/X11R6/include -D_THREAD_SAFE -E -o /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.E9d2cGZ6.o /var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.mfC1B2mW.c

/var/folders/z5/31tj_ff977n3r59bx1cwg98c0000gn/T//ffconf.mfC1B2mW.c:3:2: error: #error "unsatisfied
condition: (SDL_MAJOR_VERSION<<16 | SDL_MINOR_VERSION<<8 | SDL_PATCHLEVEL) < 0x010300"

根据对ffplay与ffmpeg中libavdevice中SDL相关的接口与SDL1和SDL2的初步对比，发现SDL2与SDL1差别还是蛮大的，要改libavdevice也是力气活，所以如果SDL1不影响太多的话，还是用SDL1吧