-nooption

[lucemia]

Note: the -nooption syntax cannot be used for boolean AVOptions, use -option 0/-option 1.

[lucemia]

https://ffmpeg.org/ffmpeg.html#Stream-specifiers-1

Options which do not take arguments are boolean options, and set the corresponding value to true. They can be set to false by prefixing the option name with "no". For example using "-nofoo" will set the boolean option with name "foo" to false.

Note: the -nooption syntax cannot be used for boolean AVOptions, use -option 0/-option 1.

When used as an input option (before -i), seeks in this input file to position. Note that in most formats it is not possible to seek exactly, so ffmpeg will seek to the closest seek point before position. When transcoding and -accurate_seek is enabled (the default), this extra segment between the seek point and position will be decoded and discarded. When doing stream copy or when -noaccurate_seek is used, it will be preserved.

-stats (global)
Print encoding progress/statistics. It is on by default, to explicitly disable it you need to specify -nostats.

-stdin
Enable interaction on standard input. On by default unless standard input is used as an input. To explicitly disable interaction you need to specify -nostdin.

Disabling interaction on standard input is useful, for example, if ffmpeg is in the background process group. Roughly the same result can be achieved with ffmpeg ... < /dev/null but it requires a shell.

-auto_conversion_filters (global)
Enable automatically inserting format conversion filters in all filter graphs, including those defined by -vf, -af, -filter_complex and -lavfi. If filter format negotiation requires a conversion, the initialization of the filters will fail. Conversions can still be performed by inserting the relevant conversion filter (scale, aresample) in the graph. On by default, to explicitly disable it you need to specify -noauto_conversion_filters.

-autorotate
Automatically rotate the video according to file metadata. Enabled by default, use -noautorotate to disable it.

-autoscale
Automatically scale the video according to the resolution of first frame. Enabled by default, use -noautoscale to disable it. When autoscale is disabled, all output frames of filter graph might not be in the same resolution and may be inadequate for some encoder/muxer. Therefore, it is not recommended to disable it unless you really know what you are doing. Disable autoscale at your own risk.

[lucemia]

int parse_option(void *optctx, const char *opt, const char *arg,
                 const OptionDef *options)
{
    static const OptionDef opt_avoptions = {
        .name       = "AVOption passthrough",
        .type       = OPT_TYPE_FUNC,
        .flags      = OPT_FUNC_ARG,
        .u.func_arg = opt_default,
    };

    const OptionDef *po;
    int ret;

    po = find_option(options, opt);
    if (!po->name && opt[0] == 'n' && opt[1] == 'o') {
        /* handle 'no' bool option */
        po = find_option(options, opt + 2);
        if ((po->name && po->type == OPT_TYPE_BOOL))
            arg = "0";
    } else if (po->type == OPT_TYPE_BOOL)
        arg = "1";

    if (!po->name)
        po = &opt_avoptions;
    if (!po->name) {
        av_log(NULL, AV_LOG_ERROR, "Unrecognized option '%s'\n", opt);
        return AVERROR(EINVAL);
    }
    if (opt_has_arg(po) && !arg) {
        av_log(NULL, AV_LOG_ERROR, "Missing argument for option '%s'\n", opt);
        return AVERROR(EINVAL);
    }