static int parse_inputs(const char **buf, AVFilterInOut **curr_inputs,
                        AVFilterInOut **open_outputs, AVClass *log_ctx)
{
    int pad = 0;

    while (**buf == '[') {
        char *name = parse_link_name(buf, log_ctx);
        AVFilterInOut *match;

        if (!name)
            return AVERROR(EINVAL);

        /* First check if the label is not in the open_outputs list */
        match = extract_inout(name, open_outputs);

        if (match) {
            av_free(name);
        } else {
            /* Not in the list, so add it as an input */
            if (!(match = av_mallocz(sizeof(AVFilterInOut))))
                return AVERROR(ENOMEM);
            match->name    = name;
            match->pad_idx = pad;
        }

        insert_inout(curr_inputs, match);

        *buf += strspn(*buf, WHITESPACES);
        pad++;
    }

    return pad;
}