static int create_filter(AVFilterContext **filt_ctx, AVFilterGraph *ctx, int index,
                         const char *filt_name, const char *args, void *log_ctx)
{
    AVFilter *filt;
    char inst_name[30];
    char *tmp_args = NULL;
    int ret;

    snprintf(inst_name, sizeof(inst_name), "Parsed_%s_%d", filt_name, index);

    filt = avfilter_get_by_name(filt_name);

    if (!filt) {
        av_log(log_ctx, AV_LOG_ERROR,
               "No such filter: '%s'\n", filt_name);
        return AVERROR(EINVAL);
    }

    *filt_ctx = avfilter_graph_alloc_filter(ctx, filt, inst_name);
    if (!*filt_ctx) {
        av_log(log_ctx, AV_LOG_ERROR,
               "Error creating filter '%s'\n", filt_name);
        return AVERROR(ENOMEM);
    }

    if (!strcmp(filt_name, "scale") && args && !strstr(args, "flags") &&
        ctx->scale_sws_opts) {
        tmp_args = av_asprintf("%s:%s",
                 args, ctx->scale_sws_opts);
        if (!tmp_args)
            return AVERROR(ENOMEM);
        args = tmp_args;
    }

    ret = avfilter_init_str(*filt_ctx, args);
    if (ret < 0) {
        av_log(log_ctx, AV_LOG_ERROR,
               "Error initializing filter '%s'", filt_name);
        if (args)
            av_log(log_ctx, AV_LOG_ERROR, " with args '%s'", args);
        av_log(log_ctx, AV_LOG_ERROR, "\n");
    }

    av_free(tmp_args);
    return ret;
}