ffmpeg_opt.c

        "set number of audio channels", "channels" },
    { "an",             OPT_AUDIO | OPT_BOOL | OPT_OFFSET | OPT_INPUT | OPT_OUTPUT,{ .off = OFFSET(audio_disable) },
        "disable audio" },
    { "acodec",         OPT_AUDIO | HAS_ARG  | OPT_PERFILE |
                        OPT_INPUT | OPT_OUTPUT,                                    { .func_arg = opt_audio_codec },
        "force audio codec ('copy' to copy stream)", "codec" },
    { "atag",           OPT_AUDIO | HAS_ARG  | OPT_EXPERT | OPT_PERFILE |
                        OPT_OUTPUT,                                                { .func_arg = opt_old2new },
        "force audio tag/fourcc", "fourcc/tag" },
    { "vol",            OPT_AUDIO | HAS_ARG  | OPT_INT,                            { &audio_volume },
        "change audio volume (256=normal)" , "volume" },
    { "sample_fmt",     OPT_AUDIO | HAS_ARG  | OPT_EXPERT | OPT_SPEC |
                        OPT_STRING | OPT_INPUT | OPT_OUTPUT,                       { .off = OFFSET(sample_fmts) },
        "set sample format", "format" },
    { "channel_layout", OPT_AUDIO | HAS_ARG  | OPT_EXPERT | OPT_PERFILE |
                        OPT_INPUT | OPT_OUTPUT,                                    { .func_arg = opt_channel_layout },
        "set channel layout", "layout" },
    { "af",             OPT_AUDIO | HAS_ARG  | OPT_PERFILE | OPT_OUTPUT,           { .func_arg = opt_audio_filters },
        "set audio filters", "filter_graph" },
    { "guess_layout_max", OPT_AUDIO | HAS_ARG | OPT_INT | OPT_SPEC | OPT_EXPERT | OPT_INPUT, { .off = OFFSET(guess_layout_max) },
      "set the maximum number of channels to try to guess the channel layout" },

    /* subtitle options */
    { "sn",     OPT_SUBTITLE | OPT_BOOL | OPT_OFFSET | OPT_INPUT | OPT_OUTPUT, { .off = OFFSET(subtitle_disable) },
        "disable subtitle" },
    { "scodec", OPT_SUBTITLE | HAS_ARG  | OPT_PERFILE | OPT_INPUT | OPT_OUTPUT, { .func_arg = opt_subtitle_codec },
        "force subtitle codec ('copy' to copy stream)", "codec" },
    { "stag",   OPT_SUBTITLE | HAS_ARG  | OPT_EXPERT  | OPT_PERFILE | OPT_OUTPUT, { .func_arg = opt_old2new }
        , "force subtitle tag/fourcc", "fourcc/tag" },
    { "fix_sub_duration", OPT_BOOL | OPT_EXPERT | OPT_SUBTITLE | OPT_SPEC | OPT_INPUT, { .off = OFFSET(fix_sub_duration) },
        "fix subtitles duration" },
    { "canvas_size", OPT_SUBTITLE | HAS_ARG | OPT_STRING | OPT_SPEC | OPT_INPUT, { .off = OFFSET(canvas_sizes) },
        "set canvas size (WxH or abbreviation)", "size" },

    /* grab options */
    { "vc", HAS_ARG | OPT_EXPERT | OPT_VIDEO, { .func_arg = opt_video_channel },
        "deprecated, use -channel", "channel" },
    { "tvstd", HAS_ARG | OPT_EXPERT | OPT_VIDEO, { .func_arg = opt_video_standard },
        "deprecated, use -standard", "standard" },
    { "isync", OPT_BOOL | OPT_EXPERT, { &input_sync }, "this option is deprecated and does nothing", "" },

    /* muxer options */
    { "muxdelay",   OPT_FLOAT | HAS_ARG | OPT_EXPERT | OPT_OFFSET | OPT_OUTPUT, { .off = OFFSET(mux_max_delay) },
        "set the maximum demux-decode delay", "seconds" },
    { "muxpreload", OPT_FLOAT | HAS_ARG | OPT_EXPERT | OPT_OFFSET | OPT_OUTPUT, { .off = OFFSET(mux_preload) },
        "set the initial demux-decode delay", "seconds" },
    { "override_ffserver", OPT_BOOL | OPT_EXPERT | OPT_OUTPUT, { &override_ffserver },
        "override the options from ffserver", "" },

    { "bsf", HAS_ARG | OPT_STRING | OPT_SPEC | OPT_EXPERT | OPT_OUTPUT, { .off = OFFSET(bitstream_filters) },
        "A comma-separated list of bitstream filters", "bitstream_filters" },
    { "absf", HAS_ARG | OPT_AUDIO | OPT_EXPERT| OPT_PERFILE | OPT_OUTPUT, { .func_arg = opt_old2new },
        "deprecated", "audio bitstream_filters" },
    { "vbsf", OPT_VIDEO | HAS_ARG | OPT_EXPERT| OPT_PERFILE | OPT_OUTPUT, { .func_arg = opt_old2new },
        "deprecated", "video bitstream_filters" },

    { "apre", HAS_ARG | OPT_AUDIO | OPT_EXPERT| OPT_PERFILE | OPT_OUTPUT,    { .func_arg = opt_preset },
        "set the audio options to the indicated preset", "preset" },
    { "vpre", OPT_VIDEO | HAS_ARG | OPT_EXPERT| OPT_PERFILE | OPT_OUTPUT,    { .func_arg = opt_preset },
        "set the video options to the indicated preset", "preset" },
    { "spre", HAS_ARG | OPT_SUBTITLE | OPT_EXPERT| OPT_PERFILE | OPT_OUTPUT, { .func_arg = opt_preset },
        "set the subtitle options to the indicated preset", "preset" },
    { "fpre", HAS_ARG | OPT_EXPERT| OPT_PERFILE | OPT_OUTPUT,                { .func_arg = opt_preset },
        "set options from indicated preset file", "filename" },
    /* data codec support */
    { "dcodec", HAS_ARG | OPT_DATA | OPT_PERFILE | OPT_EXPERT | OPT_INPUT | OPT_OUTPUT, { .func_arg = opt_data_codec },
        "force data codec ('copy' to copy stream)", "codec" },
    { "dn", OPT_BOOL | OPT_VIDEO | OPT_OFFSET | OPT_INPUT | OPT_OUTPUT, { .off = OFFSET(data_disable) },
        "disable data" },

    { NULL, },
};