H0( "Input/Output:\n" );    H0( "\n" );    H0( "  -o, --output                Specify output file\n" );    H0( "      --sar width:height      Specify Sample Aspect Ratio\n" );    H0( "      --fps <float|rational>  Specify framerate\n" );    H0( "      --seek <integer>        First frame to encode\n" );    H0( "      --frames <integer>      Maximum number of frames to encode\n" );    H0( "      --level <string>        Specify level (as defined by Annex A)\n" );    H0( "\n" );    H0( "  -v, --verbose               Print stats for each frame\n" );    H0( "      --progress              Show a progress indicator while encoding\n" );    H0( "      --quiet                 Quiet Mode\n" );    H0( "      --no-psnr               Disable PSNR computation\n" );    H0( "      --threads <integer>     Parallel encoding (uses slices)\n" );    H0( "      --thread-input          Run Avisynth in its own thread\n" );    H1( "      --no-asm                Disable all CPU optimizations\n" );    H1( "      --visualize             Show MB types overlayed on the encoded video\n" );    H1( "      --sps-id <integer>      Set SPS and PPS id numbers [%d]\n", defaults->i_sps_id );    H1( "      --aud                   Use access unit delimiters\n" );    H0( "\n" );}/***************************************************************************** * Parse: *****************************************************************************/static int  Parse( int argc, char **argv,                   x264_param_t *param, cli_opt_t *opt ){    char *psz_filename = NULL;    x264_param_t defaults = *param; //取默認參數值    char *psz;    int b_avis = 0;    int b_y4m = 0;    int b_thread_input = 0;    memset( opt, 0, sizeof(cli_opt_t) );  //清零    /* Default input file driver */    p_open_infile = open_file_yuv;                  // 給函數指針變量賦值（即函數入口地址）, 注意 open_file_yuv 為函數名    p_get_frame_total = get_frame_total_yuv;    p_read_frame = read_frame_yuv;    p_close_infile = close_file_yuv;    /* Default output file driver */    p_open_outfile = open_file_bsf;    p_set_outfile_param = set_param_bsf;    p_write_nalu = write_nalu_bsf;    p_set_eop = set_eop_bsf;    p_close_outfile = close_file_bsf;    /* Parse command line options */    for( ;; )    {        int b_error = 0;        int long_options_index = -1;#define OPT_FRAMES 256#define OPT_SEEK 257#define OPT_QPFILE 258#define OPT_THREAD_INPUT 259#define OPT_QUIET 260#define OPT_PROGRESS 261#define OPT_VISUALIZE 262#define OPT_LONGHELP 263        static struct option long_options[] =        {            { "help",    no_argument,       NULL, 'h' },            { "longhelp",no_argument,       NULL, OPT_LONGHELP },            { "version", no_argument,       NULL, 'V' },            { "bitrate", required_argument, NULL, 'B' },            { "bframes", required_argument, NULL, 'b' },            { "no-b-adapt", no_argument,    NULL, 0 },            { "b-bias",  required_argument, NULL, 0 },            { "b-pyramid", no_argument,     NULL, 0 },            { "min-keyint",required_argument,NULL,'i' },            { "keyint",  required_argument, NULL, 'I' },            { "scenecut",required_argument, NULL, 0 },            { "nf",      no_argument,       NULL, 0 },            { "filter",  required_argument, NULL, 'f' },            { "no-cabac",no_argument,       NULL, 0 },            { "qp",      required_argument, NULL, 'q' },            { "qpmin",   required_argument, NULL, 0 },            { "qpmax",   required_argument, NULL, 0 },            { "qpstep",  required_argument, NULL, 0 },            { "crf",     required_argument, NULL, 0 },            { "ref",     required_argument, NULL, 'r' },            { "no-asm",  no_argument,       NULL, 0 },            { "sar",     required_argument, NULL, 0 },            { "fps",     required_argument, NULL, 0 },            { "frames",  required_argument, NULL, OPT_FRAMES },            { "seek",    required_argument, NULL, OPT_SEEK },            { "output",  required_argument, NULL, 'o' },            { "analyse", required_argument, NULL, 'A' },            { "direct",  required_argument, NULL, 0 },            { "weightb", no_argument,       NULL, 'w' },            { "me",      required_argument, NULL, 0 },            { "merange", required_argument, NULL, 0 },            { "subme",   required_argument, NULL, 'm' },            { "b-rdo",   no_argument,       NULL, 0 },            { "mixed-refs", no_argument,    NULL, 0 },            { "no-chroma-me", no_argument,  NULL, 0 },            { "bime",    no_argument,       NULL, 0 },            { "8x8dct",  no_argument,       NULL, '8' },            { "trellis", required_argument, NULL, 't' },            { "no-fast-pskip", no_argument, NULL, 0 },            { "no-dct-decimate", no_argument, NULL, 0 },            { "level",   required_argument, NULL, 0 },            { "ratetol", required_argument, NULL, 0 },            { "vbv-maxrate", required_argument, NULL, 0 },            { "vbv-bufsize", required_argument, NULL, 0 },            { "vbv-init", required_argument,NULL,  0 },            { "ipratio", required_argument, NULL, 0 },            { "pbratio", required_argument, NULL, 0 },            { "chroma-qp-offset", required_argument, NULL, 0 },            { "pass",    required_argument, NULL, 'p' },            { "stats",   required_argument, NULL, 0 },            { "rceq",    required_argument, NULL, 0 },            { "qcomp",   required_argument, NULL, 0 },            { "qblur",   required_argument, NULL, 0 },            { "cplxblur",required_argument, NULL, 0 },            { "zones",   required_argument, NULL, 0 },            { "qpfile",  required_argument, NULL, OPT_QPFILE },            { "threads", required_argument, NULL, 0 },            { "thread-input", no_argument,  NULL, OPT_THREAD_INPUT },            { "no-psnr", no_argument,       NULL, 0 },            { "quiet",   no_argument,       NULL, OPT_QUIET },            { "verbose", no_argument,       NULL, 'v' },            { "progress",no_argument,       NULL, OPT_PROGRESS },            { "visualize",no_argument,      NULL, OPT_VISUALIZE },            { "sps-id",  required_argument, NULL, 0 },            { "aud",     no_argument,       NULL, 0 },            { "nr",      required_argument, NULL, 0 },            { "cqm",     required_argument, NULL, 0 },            { "cqmfile", required_argument, NULL, 0 },            { "cqm4",    required_argument, NULL, 0 },            { "cqm4i",   required_argument, NULL, 0 },            { "cqm4iy",  required_argument, NULL, 0 },            { "cqm4ic",  required_argument, NULL, 0 },            { "cqm4p",   required_argument, NULL, 0 },            { "cqm4py",  required_argument, NULL, 0 },            { "cqm4pc",  required_argument, NULL, 0 },            { "cqm8",    required_argument, NULL, 0 },            { "cqm8i",   required_argument, NULL, 0 },            { "cqm8p",   required_argument, NULL, 0 },            { "overscan", required_argument, NULL, 0 },            { "videoformat", required_argument, NULL, 0 },            { "fullrange", required_argument, NULL, 0 },            { "colorprim", required_argument, NULL, 0 },            { "transfer", required_argument, NULL, 0 },            { "colormatrix", required_argument, NULL, 0 },            { "chromaloc", required_argument, NULL, 0 },            {0, 0, 0, 0}        };        int c = getopt_long( argc, argv, "8A:B:b:f:hI:i:m:o:p:q:r:t:Vvw",                             long_options, &long_options_index);     //默認設置時返回 c=111 即 "o" , 作用?        if( c == -1 )          {            break;        }        switch( c )        {            case 'h':                Help( &defaults, 0 ); //static void Help( x264_param_t *defaults, int b_longhelp )                exit(0);            case OPT_LONGHELP:                Help( &defaults, 1 );                exit(0);            case 'V':#ifdef X264_POINTVER                printf( "x264 "X264_POINTVER"\n" );#else                printf( "x264 0.%d.X\n", X264_BUILD );#endif                exit(0);            case OPT_FRAMES:                param->i_frame_total = atoi( optarg );                break;            case OPT_SEEK:                opt->i_seek = atoi( optarg );                break;            case 'o':                if( !strncasecmp(optarg + strlen(optarg) - 4, ".mp4", 4) )                {#ifdef MP4_OUTPUT                    p_open_outfile = open_file_mp4;                    p_write_nalu = write_nalu_mp4;                    p_set_outfile_param = set_param_mp4;                    p_set_eop = set_eop_mp4;                    p_close_outfile = close_file_mp4;#else                    fprintf( stderr, "x264 [error]: not compiled with MP4 output support\n" );                    return -1;#endif                }                else if( !strncasecmp(optarg + strlen(optarg) - 4, ".mkv", 4) )                {                    p_open_outfile = open_file_mkv;                    p_write_nalu = write_nalu_mkv;                    p_set_outfile_param = set_param_mkv;                    p_set_eop = set_eop_mkv;                    p_close_outfile = close_file_mkv;                }                if( !strcmp(optarg, "-") )                    opt->hout = stdout;                else if( p_open_outfile( optarg, &opt->hout ) )                {                    fprintf( stderr, "x264 [error]: can't open output file `%s'\n", optarg );                    return -1;                }                break;            case OPT_QPFILE:   //  #define OPT_QPFILE 258                opt->qpfile = fopen( optarg, "r" );                if( !opt->qpfile )                {                    fprintf( stderr, "x264 [error]: can't open `%s'\n", optarg );                    return -1;                }                param->i_scenecut_threshold = -1;                param->b_bframe_adaptive = 0;                break;            case OPT_THREAD_INPUT:                b_thread_input = 1;                break;            case OPT_QUIET:                param->i_log_level = X264_LOG_NONE;                param->analyse.b_psnr = 0;                break;            case 'v':                param->i_log_level = X264_LOG_DEBUG;                break;            case OPT_PROGRESS:                opt->b_progress = 1;                break;            case OPT_VISUALIZE:#ifdef VISUALIZE                param->b_visualize = 1;                b_exit_on_ctrl_c = 1;#else                fprintf( stderr, "x264 [warning]: not compiled with visualization support\n" );#endif                break;            default:            {                int i;                if( long_options_index < 0 )                {                    for( i = 0; long_options[i].name; i++ )                        if( long_options[i].val == c )                        {                            long_options_index = i;                            break;                        }                    if( long_options_index < 0 )                    {                        /* getopt_long already printed an error message */                        return -1;                    }                }                b_error |= x264_param_parse( param, long_options[long_options_index].name, optarg ? optarg : "true" );            }        }        if( b_error )          {            const char *name = long_options_index > 0 ? long_options[long_options_index].name : argv[optind-2];            fprintf( stderr, "x264 [error]: invalid argument: %s = %s\n", name, optarg );            return -1;        }    }