int ff_wms_parse_sdp_a_line(AVFormatContext *s, const char *p)
{
    int ret = 0;
    if (av_strstart(p, "pgmpu:data:application/vnd.ms.wms-hdr.asfv1;base64,", &p)) {
        AVIOContext pb = { 0 };
        RTSPState *rt = s->priv_data;
        AVDictionary *opts = NULL;
        int len = strlen(p) * 6 / 8;
        char *buf = av_mallocz(len);
        AVInputFormat *iformat;

        if (!buf)
            return AVERROR(ENOMEM);
        av_base64_decode(buf, p, len);

        if (rtp_asf_fix_header(buf, len) < 0)
            av_log(s, AV_LOG_ERROR,
                   "Failed to fix invalid RTSP-MS/ASF min_pktsize\n");
        init_packetizer(&pb, buf, len);
        if (rt->asf_ctx) {
            avformat_close_input(&rt->asf_ctx);
        }

        if (!(iformat = av_find_input_format("asf")))
            return AVERROR_DEMUXER_NOT_FOUND;

        rt->asf_ctx = avformat_alloc_context();
        if (!rt->asf_ctx) {
            av_free(buf);
            return AVERROR(ENOMEM);
        }
        rt->asf_ctx->pb      = &pb;
        av_dict_set(&opts, "no_resync_search", "1", 0);

        if ((ret = ff_copy_whiteblacklists(rt->asf_ctx, s)) < 0) {
            av_dict_free(&opts);
            return ret;
        }

        ret = avformat_open_input(&rt->asf_ctx, "", iformat, &opts);
        av_dict_free(&opts);
        if (ret < 0) {
            av_free(buf);
            return ret;
        }
        av_dict_copy(&s->metadata, rt->asf_ctx->metadata, 0);
        rt->asf_pb_pos = avio_tell(&pb);
        av_free(buf);
        rt->asf_ctx->pb = NULL;
    }
    return ret;
}