iOS编译ffmpeg过程中遇到的问题

Undefined symbols for architecture armv7:
  "_av_read_frame", referenced from:
      -[KxMovieDecoder decodeFrames:] in KxMovieDecoder.o
  "_avformat_open_input", referenced from:
      -[KxMovieDecoder openInput:] in KxMovieDecoder.o
  "_avformat_find_stream_info", referenced from:
      -[KxMovieDecoder openInput:] in KxMovieDecoder.o
  "_av_register_all", referenced from:
      +[KxMovieDecoder initialize] in KxMovieDecoder.o
  "_avformat_close_input", referenced from:
      -[KxMovieDecoder openInput:] in KxMovieDecoder.o
      -[KxMovieDecoder closeFile] in KxMovieDecoder.o
  "_avformat_alloc_context", referenced from:
      -[KxMovieDecoder openInput:] in KxMovieDecoder.o
  "_av_dump_format", referenced from:
      -[KxMovieDecoder openInput:] in KxMovieDecoder.o
  "_avformat_network_init", referenced from:
      +[KxMovieDecoder initialize] in KxMovieDecoder.o
      -[KxMovieDecoder openFile:error:] in KxMovieDecoder.o
  "_avformat_free_context", referenced from:
      -[KxMovieDecoder openInput:] in KxMovieDecoder.o
  "_avformat_seek_file", referenced from:
      -[KxMovieDecoder setPosition:] in KxMovieDecoder.o
ld: symbol(s) not found for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)

在编译ffmpeg的过程中，遇到上面的问题，应该如何解决？
主要是这个问题：

 "_avformat_seek_file", referenced from:
      -[KxMovieDecoder setPosition:] in KxMovieDecoder.o

还有这个问题：

"_avpicture_deinterlace",referenced from:
-[KxMovieDecoder setPosition:] in KxMovieDecoder.o
ld: symbol(s) not found for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)

搞的我的头都大了，谢谢大家。