av_opt_get_int (o->g->swr_opts, "filter_type" , 0, &ost->swr_filter_type);
av_opt_get_int (o->g->swr_opts, "dither_method", 0, &ost->swr_dither_method);
av_opt_get_double(o->g->swr_opts, "dither_scale" , 0, &ost->swr_dither_scale);
av_opt_get_int (o->g->swr_opts, "filter_type" , 0, &ost->swr_filter_type);
av_opt_get_int (o->g->swr_opts, "dither_method", 0, &ost->swr_dither_method);
av_opt_get_double(o->g->swr_opts, "dither_scale" , 0, &ost->swr_dither_scale);