ffmpeg.c

        if (opt[0] == '-' && opt[1] != '\0') {
            po = options;
            while (po->name != NULL) {
                if (!strcmp(opt + 1, po->name))
                    break;
                po++;
            }
            if (!po->name) {
                fprintf(stderr, "%s: unrecognized option '%s'\n", argv[0], opt);
                exit(1);
            }
            arg = NULL;
            if (po->flags & HAS_ARG)
                arg = argv[optindex++];
            if (po->flags & OPT_STRING) {
                char *str;
                str = strdup(arg);
                *po->u.str_arg = str;
            } else if (po->flags & OPT_BOOL) {
                *po->u.int_arg = 1;
            } else {
                po->u.func_arg(arg);
            }
        } else {
            if (!do_play) {
                opt_output_file(opt);
            } else {
                opt_input_file(opt);
            }
        }
    }


    if (!do_play) {
        /* file converter / grab */
        if (nb_output_files <= 0) {
            fprintf(stderr, "Must supply at least one output file\n");
            exit(1);
        }
        
        if (nb_input_files == 0) {
            prepare_grab();
        }
    } else {
        /* player */
        if (nb_input_files <= 0) {
            fprintf(stderr, "Must supply at least one input file\n");
            exit(1);
        }
        prepare_play();
    }

    ti = getutime();
    av_encode(output_files, nb_output_files, input_files, nb_input_files, 
              stream_maps, nb_stream_maps);
    ti = getutime() - ti;
    if (do_benchmark) {
        printf("bench: utime=%0.3fs\n", ti / 1000000.0);
    }

    /* close files */
    for(i=0;i<nb_output_files;i++) {
        if (!(output_files[i]->format->flags & AVFMT_NOFILE)) 
            url_fclose(&output_files[i]->pb);
    }
    for(i=0;i<nb_input_files;i++) {
        if (!(input_files[i]->format->flags & AVFMT_NOFILE)) 
            url_fclose(&input_files[i]->pb);
    }

    return 0;
}