Using libav without command line?
===

I using this command bellow for converting file 
"./avconv -i inputFile -vcodec libx264 -trellis 2 -crf 23 -tune psnr -vf crop='trunc(iw/2)*2:trunc(ih/2)*2' -y outputFile" 
But, I don't want to using this command, I want to make a function like convert(char *inputFile, char *outputFile). (The option of my function like option in command line) 
And then I will call it from my main function 
for example 

    int main(){ 
        convert(in01, out01); 
        convert(in02, out02); 
        convert(in03, out03); 
        return 0; 
    } 
I alse read [the article][1] But it is not clealy for me.
Could anyone tell me how to solve this problem? I have google many time but do not find the solution. 


  [1]: http://stackoverflow.com/questions/2401764/can-ffmpeg-be-used-as-a-library-instead-of-a-standalone-program