static ASS_RenderPriv *get_render_priv(ASS_Renderer *render_priv,
                                       ASS_Event *event)
{
    if (!event->render_priv) {
        event->render_priv = calloc(1, sizeof(ASS_RenderPriv));
        if (!event->render_priv)
            return NULL;
    }
    if (render_priv->render_id != event->render_priv->render_id) {
        memset(event->render_priv, 0, sizeof(ASS_RenderPriv));
        event->render_priv->render_id = render_priv->render_id;
    }

    return event->render_priv;
}
Unknown