{    RTPDemuxContext *s;    s = av_mallocz(sizeof(RTPDemuxContext));    if (!s)        return NULL;    s->payload_type = payload_type;    s->last_rtcp_ntp_time = AV_NOPTS_VALUE;    s->first_rtcp_ntp_time = AV_NOPTS_VALUE;    s->ic = s1;    s->st = st;    s->rtp_payload_data = rtp_payload_data;    rtp_init_statistics(&s->statistics, 0); // do we know the initial sequence from sdp?    av_set_pts_info(s->st, 32, 1, 90000);    if (!strcmp(ff_rtp_enc_name(payload_type), "MP2T")) {        s->ts = mpegts_parse_open(s->ic);        if (s->ts == NULL) {            av_free(s);            return NULL;        }    } else {        switch(st->codec->codec_id) {        case CODEC_ID_MPEG1VIDEO:        case CODEC_ID_MPEG2VIDEO:        case CODEC_ID_MP2:        case CODEC_ID_MP3:        case CODEC_ID_MPEG4:        case CODEC_ID_H264:            st->need_parsing = AVSTREAM_PARSE_FULL;            break;        default:            if (st->codec->codec_type == CODEC_TYPE_AUDIO) {                av_set_pts_info(st, 32, 1, st->codec->sample_rate);            }            break;        }    }    // needed to send back RTCP RR in RTSP sessions    s->rtp_ctx = rtpc;    gethostname(s->hostname, sizeof(s->hostname));    return s;}static int rtp_parse_mp4_au(RTPDemuxContext *s, const uint8_t *buf){    int au_headers_length, au_header_size, i;    GetBitContext getbitcontext;    rtp_payload_data_t *infos;    infos = s->rtp_payload_data;    if (infos == NULL)        return -1;    /* decode the first 2 bytes where the AUHeader sections are stored       length in bits */    au_headers_length = AV_RB16(buf);    if (au_headers_length > RTP_MAX_PACKET_LENGTH)      return -1;    infos->au_headers_length_bytes = (au_headers_length + 7) / 8;    /* skip AU headers length section (2 bytes) */    buf += 2;    init_get_bits(&getbitcontext, buf, infos->au_headers_length_bytes * 8);    /* XXX: Wrong if optionnal additional sections are present (cts, dts etc...) */    au_header_size = infos->sizelength + infos->indexlength;    if (au_header_size <= 0 || (au_headers_length % au_header_size != 0))        return -1;    infos->nb_au_headers = au_headers_length / au_header_size;    infos->au_headers = av_malloc(sizeof(struct AUHeaders) * infos->nb_au_headers);    /* XXX: We handle multiple AU Section as only one (need to fix this for interleaving)       In my test, the FAAD decoder does not behave correctly when sending each AU one by one       but does when sending the whole as one big packet...  */    infos->au_headers[0].size = 0;    infos->au_headers[0].index = 0;    for (i = 0; i < infos->nb_au_headers; ++i) {        infos->au_headers[0].size += get_bits_long(&getbitcontext, infos->sizelength);        infos->au_headers[0].index = get_bits_long(&getbitcontext, infos->indexlength);    }    infos->nb_au_headers = 1;    return 0;}/** * This was the second switch in rtp_parse packet.  Normalizes time, if required, sets stream_index, etc. */static void finalize_packet(RTPDemuxContext *s, AVPacket *pkt, uint32_t timestamp){    if (s->last_rtcp_ntp_time != AV_NOPTS_VALUE) {        int64_t addend;        int delta_timestamp;        /* compute pts from timestamp with received ntp_time */        delta_timestamp = timestamp - s->last_rtcp_timestamp;        /* convert to the PTS timebase */        addend = av_rescale(s->last_rtcp_ntp_time - s->first_rtcp_ntp_time, s->st->time_base.den, (uint64_t)s->st->time_base.num << 32);        pkt->pts = addend + delta_timestamp;    }    pkt->stream_index = s->st->index;}/** * Parse an RTP or RTCP packet directly sent as a buffer. * @param s RTP parse context. * @param pkt returned packet * @param buf input buffer or NULL to read the next packets * @param len buffer len * @return 0 if a packet is returned, 1 if a packet is returned and more can follow * (use buf as NULL to read the next). -1 if no packet (error or no more packet). */int rtp_parse_packet(RTPDemuxContext *s, AVPacket *pkt,                     const uint8_t *buf, int len){    unsigned int ssrc, h;    int payload_type, seq, ret, flags = 0;    AVStream *st;    uint32_t timestamp;    int rv= 0;    if (!buf) {        /* return the next packets, if any */        if(s->st && s->parse_packet) {            timestamp= 0; ///< Should not be used if buf is NULL, but should be set to the timestamp of the packet returned....            rv= s->parse_packet(s, pkt, &timestamp, NULL, 0, flags);            finalize_packet(s, pkt, timestamp);            return rv;        } else {            // TODO: Move to a dynamic packet handler (like above)            if (s->read_buf_index >= s->read_buf_size)                return -1;            ret = mpegts_parse_packet(s->ts, pkt, s->buf + s->read_buf_index,                                      s->read_buf_size - s->read_buf_index);            if (ret < 0)                return -1;            s->read_buf_index += ret;            if (s->read_buf_index < s->read_buf_size)                return 1;            else                return 0;        }    }    if (len < 12)        return -1;    if ((buf[0] & 0xc0) != (RTP_VERSION << 6))        return -1;    if (buf[1] >= 200 && buf[1] <= 204) {        rtcp_parse_packet(s, buf, len);        return -1;    }    payload_type = buf[1] & 0x7f;    seq  = AV_RB16(buf + 2);    timestamp = AV_RB32(buf + 4);    ssrc = AV_RB32(buf + 8);    /* store the ssrc in the RTPDemuxContext */    s->ssrc = ssrc;    /* NOTE: we can handle only one payload type */    if (s->payload_type != payload_type)        return -1;    st = s->st;    // only do something with this if all the rtp checks pass...    if(!rtp_valid_packet_in_sequence(&s->statistics, seq))    {        av_log(st?st->codec:NULL, AV_LOG_ERROR, "RTP: PT=%02x: bad cseq %04x expected=%04x\n",               payload_type, seq, ((s->seq + 1) & 0xffff));        return -1;    }    s->seq = seq;    len -= 12;    buf += 12;    if (!st) {        /* specific MPEG2TS demux support */        ret = mpegts_parse_packet(s->ts, pkt, buf, len);        if (ret < 0)            return -1;        if (ret < len) {            s->read_buf_size = len - ret;            memcpy(s->buf, buf + ret, s->read_buf_size);            s->read_buf_index = 0;            return 1;        }    } else if (s->parse_packet) {        rv = s->parse_packet(s, pkt, &timestamp, buf, len, flags);    } else {        // at this point, the RTP header has been stripped;  This is ASSUMING that there is only 1 CSRC, which in't wise.        switch(st->codec->codec_id) {        case CODEC_ID_MP2:            /* better than nothing: skip mpeg audio RTP header */            if (len <= 4)                return -1;            h = AV_RB32(buf);            len -= 4;            buf += 4;            av_new_packet(pkt, len);            memcpy(pkt->data, buf, len);            break;        case CODEC_ID_MPEG1VIDEO:        case CODEC_ID_MPEG2VIDEO:            /* better than nothing: skip mpeg video RTP header */            if (len <= 4)                return -1;            h = AV_RB32(buf);            buf += 4;            len -= 4;            if (h & (1 << 26)) {                /* mpeg2 */                if (len <= 4)                    return -1;                buf += 4;                len -= 4;            }            av_new_packet(pkt, len);            memcpy(pkt->data, buf, len);            break;            // moved from below, verbatim.  this is because this section handles packets, and the lower switch handles            // timestamps.            // TODO: Put this into a dynamic packet handler...        case CODEC_ID_AAC:            if (rtp_parse_mp4_au(s, buf))                return -1;            {                rtp_payload_data_t *infos = s->rtp_payload_data;                if (infos == NULL)                    return -1;                buf += infos->au_headers_length_bytes + 2;                len -= infos->au_headers_length_bytes + 2;                /* XXX: Fixme we only handle the case where rtp_parse_mp4_au define                    one au_header */                av_new_packet(pkt, infos->au_headers[0].size);                memcpy(pkt->data, buf, infos->au_headers[0].size);                buf += infos->au_headers[0].size;                len -= infos->au_headers[0].size;            }            s->read_buf_size = len;            rv= 0;            break;        default:            av_new_packet(pkt, len);            memcpy(pkt->data, buf, len);            break;        }        // now perform timestamp things....        finalize_packet(s, pkt, timestamp);    }    return rv;}void rtp_parse_close(RTPDemuxContext *s){    // TODO: fold this into the protocol specific data fields.    if (!strcmp(ff_rtp_enc_name(s->payload_type), "MP2T")) {        mpegts_parse_close(s->ts);    }    av_free(s);}