cannot compile the library !!!

[tachyonus]

ubuntu 14.04 32 bits

i got this chinese message while compiling :

Linking CXX executable openshot-example
libopenshot.so.0.0.6: undefined reference to `swr_free'
libopenshot.so.0.0.6: undefined reference to `swr_init'
libopenshot.so.0.0.6: undefined reference to `swr_close'
libopenshot.so.0.0.6: undefined reference to `swr_convert'
libopenshot.so.0.0.6: undefined reference to `swr_alloc'
libopenshot.so.0.0.6: undefined reference to `swr_is_initialized'
collect2: error: ld returned 1 exit status

what should I understand ???