rtsp.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

    int content_length, line_count;
    unsigned char *content = NULL;

    memset(reply, 0, sizeof(RTSPHeader));

    rt->seq++;
    av_strlcpy(buf, cmd, sizeof(buf));
    snprintf(buf1, sizeof(buf1), "CSeq: %d\r\n", rt->seq);
    av_strlcat(buf, buf1, sizeof(buf));
    if (rt->session_id[0] != '\0' && !strstr(cmd, "\nIf-Match:")) {
        snprintf(buf1, sizeof(buf1), "Session: %s\r\n", rt->session_id);
        av_strlcat(buf, buf1, sizeof(buf));
    }
    av_strlcat(buf, "\r\n", sizeof(buf));
#ifdef DEBUG
    printf("Sending:\n%s--\n", buf);
#endif
    url_write(rt->rtsp_hd, buf, strlen(buf));

    /* parse reply (XXX: use buffers) */
    line_count = 0;
    rt->last_reply[0] = '\0';
    for(;;) {
        q = buf;
        for(;;) {
            if (url_readbuf(rt->rtsp_hd, &ch, 1) != 1)
                break;
            if (ch == '\n')
                break;
            if (ch == '$') {
                /* XXX: only parse it if first char on line ? */
                rtsp_skip_packet(s);
            } else if (ch != '\r') {
                if ((q - buf) < sizeof(buf) - 1)
                    *q++ = ch;
            }
        }
        *q = '\0';
#ifdef DEBUG
        printf("line='%s'\n", buf);
#endif
        /* test if last line */
        if (buf[0] == '\0')
            break;
        p = buf;
        if (line_count == 0) {
            /* get reply code */
            get_word(buf1, sizeof(buf1), &p);
            get_word(buf1, sizeof(buf1), &p);
            reply->status_code = atoi(buf1);
        } else {
            rtsp_parse_line(reply, p);
            av_strlcat(rt->last_reply, p,    sizeof(rt->last_reply));
            av_strlcat(rt->last_reply, "\n", sizeof(rt->last_reply));
        }
        line_count++;
    }

    if (rt->session_id[0] == '\0' && reply->session_id[0] != '\0')
        av_strlcpy(rt->session_id, reply->session_id, sizeof(rt->session_id));

    content_length = reply->content_length;
    if (content_length > 0) {
        /* leave some room for a trailing '\0' (useful for simple parsing) */
        content = av_malloc(content_length + 1);
        (void)url_readbuf(rt->rtsp_hd, content, content_length);
        content[content_length] = '\0';
    }
    if (content_ptr)
        *content_ptr = content;
    else
        av_free(content);
}


/* close and free RTSP streams */
static void rtsp_close_streams(RTSPState *rt)
{
    int i;
    RTSPStream *rtsp_st;

    for(i=0;i<rt->nb_rtsp_streams;i++) {
        rtsp_st = rt->rtsp_streams[i];
        if (rtsp_st) {
            if (rtsp_st->rtp_ctx)
                rtp_parse_close(rtsp_st->rtp_ctx);
            if (rtsp_st->rtp_handle)
                url_close(rtsp_st->rtp_handle);
            if (rtsp_st->dynamic_handler && rtsp_st->dynamic_protocol_context)
                rtsp_st->dynamic_handler->close(rtsp_st->dynamic_protocol_context);
        }
        av_free(rtsp_st);
    }
    av_free(rt->rtsp_streams);
}

static int rtsp_read_header(AVFormatContext *s,
                            AVFormatParameters *ap)
{
    RTSPState *rt = s->priv_data;
    char host[1024], path[1024], tcpname[1024], cmd[2048], *option_list, *option;
    URLContext *rtsp_hd;
    int port, i, j, ret, err;
    RTSPHeader reply1, *reply = &reply1;
    unsigned char *content = NULL;
    RTSPStream *rtsp_st;
    int protocol_mask = 0;
    AVStream *st;

    /* extract hostname and port */
    url_split(NULL, 0, NULL, 0,
              host, sizeof(host), &port, path, sizeof(path), s->filename);
    if (port < 0)
        port = RTSP_DEFAULT_PORT;

    /* search for options */
    option_list = strchr(path, '?');
    if (option_list) {
        /* remove the options from the path */
        *option_list++ = 0;
        while(option_list) {
            /* move the option pointer */
            option = option_list;
            option_list = strchr(option_list, '&');
            if (option_list)
                *(option_list++) = 0;
            /* handle the options */
            if (strcmp(option, "udp") == 0)
                protocol_mask = (1<< RTSP_PROTOCOL_RTP_UDP);
            else if (strcmp(option, "multicast") == 0)
                protocol_mask = (1<< RTSP_PROTOCOL_RTP_UDP_MULTICAST);
            else if (strcmp(option, "tcp") == 0)
                protocol_mask = (1<< RTSP_PROTOCOL_RTP_TCP);
        }
    }

    if (!protocol_mask)
        protocol_mask = rtsp_default_protocols;

    /* open the tcp connexion */
    snprintf(tcpname, sizeof(tcpname), "tcp://%s:%d", host, port);
    if (url_open(&rtsp_hd, tcpname, URL_RDWR) < 0)
        return AVERROR(EIO);
    rt->rtsp_hd = rtsp_hd;
    rt->seq = 0;

    /* describe the stream */
    snprintf(cmd, sizeof(cmd),
             "DESCRIBE %s RTSP/1.0\r\n"
             "Accept: application/sdp\r\n",
             s->filename);
    rtsp_send_cmd(s, cmd, reply, &content);
    if (!content) {
        err = AVERROR_INVALIDDATA;
        goto fail;
    }
    if (reply->status_code != RTSP_STATUS_OK) {
        err = AVERROR_INVALIDDATA;
        goto fail;
    }

    /* now we got the SDP description, we parse it */
    ret = sdp_parse(s, (const char *)content);
    av_freep(&content);
    if (ret < 0) {
        err = AVERROR_INVALIDDATA;
        goto fail;
    }

    /* for each stream, make the setup request */
    /* XXX: we assume the same server is used for the control of each
       RTSP stream */

    for(j = RTSP_RTP_PORT_MIN, i = 0; i < rt->nb_rtsp_streams; ++i) {
        char transport[2048];

        rtsp_st = rt->rtsp_streams[i];

        /* compute available transports */
        transport[0] = '\0';

        /* RTP/UDP */
        if (protocol_mask & (1 << RTSP_PROTOCOL_RTP_UDP)) {
            char buf[256];

            /* first try in specified port range */
            if (RTSP_RTP_PORT_MIN != 0) {
                while(j <= RTSP_RTP_PORT_MAX) {
                    snprintf(buf, sizeof(buf), "rtp://?localport=%d", j);
                    if (url_open(&rtsp_st->rtp_handle, buf, URL_RDWR) == 0) {
                        j += 2; /* we will use two port by rtp stream (rtp and rtcp) */
                        goto rtp_opened;
                    }
                }
            }

/*            then try on any port
**            if (url_open(&rtsp_st->rtp_handle, "rtp://", URL_RDONLY) < 0) {
**                err = AVERROR_INVALIDDATA;
**                goto fail;
**            }
*/

        rtp_opened:
            port = rtp_get_local_port(rtsp_st->rtp_handle);
            if (transport[0] != '\0')
                av_strlcat(transport, ",", sizeof(transport));
            snprintf(transport + strlen(transport), sizeof(transport) - strlen(transport) - 1,
                     "RTP/AVP/UDP;unicast;client_port=%d-%d",
                     port, port + 1);
        }

        /* RTP/TCP */
        else if (protocol_mask & (1 << RTSP_PROTOCOL_RTP_TCP)) {
            if (transport[0] != '\0')
                av_strlcat(transport, ",", sizeof(transport));
            snprintf(transport + strlen(transport), sizeof(transport) - strlen(transport) - 1,
                     "RTP/AVP/TCP");
        }

        else if (protocol_mask & (1 << RTSP_PROTOCOL_RTP_UDP_MULTICAST)) {
            if (transport[0] != '\0')
                av_strlcat(transport, ",", sizeof(transport));
            snprintf(transport + strlen(transport),
                     sizeof(transport) - strlen(transport) - 1,
                     "RTP/AVP/UDP;multicast");
        }
        snprintf(cmd, sizeof(cmd),
                 "SETUP %s RTSP/1.0\r\n"
                 "Transport: %s\r\n",
                 rtsp_st->control_url, transport);
        rtsp_send_cmd(s, cmd, reply, NULL);
        if (reply->status_code != RTSP_STATUS_OK ||
            reply->nb_transports != 1) {
            err = AVERROR_INVALIDDATA;
            goto fail;
        }

        /* XXX: same protocol for all streams is required */
        if (i > 0) {
            if (reply->transports[0].protocol != rt->protocol) {
                err = AVERROR_INVALIDDATA;
                goto fail;
            }
        } else {
            rt->protocol = reply->transports[0].protocol;
        }

        /* close RTP connection if not choosen */
        if (reply->transports[0].protocol != RTSP_PROTOCOL_RTP_UDP &&
            (protocol_mask & (1 << RTSP_PROTOCOL_RTP_UDP))) {
            url_close(rtsp_st->rtp_handle);
            rtsp_st->rtp_handle = NULL;
        }

        switch(reply->transports[0].protocol) {
        case RTSP_PROTOCOL_RTP_TCP:
            rtsp_st->interleaved_min = reply->transports[0].interleaved_min;
            rtsp_st->interleaved_max = reply->transports[0].interleaved_max;
            break;

        case RTSP_PROTOCOL_RTP_UDP:
            {
                char url[1024];

                /* XXX: also use address if specified */
                snprintf(url, sizeof(url), "rtp://%s:%d",
                         host, reply->transports[0].server_port_min);
                if (rtp_set_remote_url(rtsp_st->rtp_handle, url) < 0) {
                    err = AVERROR_INVALIDDATA;
                    goto fail;
                }
            }
            break;
        case RTSP_PROTOCOL_RTP_UDP_MULTICAST:
            {
                char url[1024];
                struct in_addr in;

                in.s_addr = htonl(reply->transports[0].destination);
                snprintf(url, sizeof(url), "rtp://%s:%d?multicast=1&ttl=%d",
                         inet_ntoa(in),
                         reply->transports[0].port_min,
                         reply->transports[0].ttl);
                if (url_open(&rtsp_st->rtp_handle, url, URL_RDWR) < 0) {
                    err = AVERROR_INVALIDDATA;
                    goto fail;
                }
            }
            break;
        }
        /* open the RTP context */
        st = NULL;
        if (rtsp_st->stream_index >= 0)
            st = s->streams[rtsp_st->stream_index];
        if (!st)
            s->ctx_flags |= AVFMTCTX_NOHEADER;
        rtsp_st->rtp_ctx = rtp_parse_open(s, st, rtsp_st->rtp_handle, rtsp_st->sdp_payload_type, &rtsp_st->rtp_payload_data);

        if (!rtsp_st->rtp_ctx) {
            err = AVERROR(ENOMEM);
            goto fail;
        } else {
            if(rtsp_st->dynamic_handler) {
                rtsp_st->rtp_ctx->dynamic_protocol_context= rtsp_st->dynamic_protocol_context;
                rtsp_st->rtp_ctx->parse_packet= rtsp_st->dynamic_handler->parse_packet;
            }
        }
    }

    rt->state = RTSP_STATE_IDLE;
    rt->seek_timestamp = 0; /* default is to start stream at position
                               zero */
    if (ap->initial_pause) {
        /* do not start immediately */
    } else {
        if (rtsp_read_play(s) < 0) {
            err = AVERROR_INVALIDDATA;
            goto fail;
        }
    }
    return 0;
 fail:
    rtsp_close_streams(rt);
    av_freep(&content);
    url_close(rt->rtsp_hd);
    return err;
}

static int tcp_read_packet(AVFormatContext *s, RTSPStream **prtsp_st,
                           uint8_t *buf, int buf_size)
{
    RTSPState *rt = s->priv_data;
    int id, len, i, ret;
    RTSPStream *rtsp_st;

#ifdef DEBUG_RTP_TCP
    printf("tcp_read_packet:\n");
#endif
 redo:
    for(;;) {
        ret = url_readbuf(rt->rtsp_hd, buf, 1);
#ifdef DEBUG_RTP_TCP
        printf("ret=%d c=%02x [%c]\n", ret, buf[0], buf[0]);
#endif
        if (ret != 1)
            return -1;
        if (buf[0] == '$')
            break;
    }
    ret = url_readbuf(rt->rtsp_hd, buf, 3);
    if (ret != 3)
        return -1;
    id = buf[0];
    len = AV_RB16(buf + 1);
#ifdef DEBUG_RTP_TCP
    printf("id=%d len=%d\n", id, len);
#endif
    if (len > buf_size || len < 12)
        goto redo;
    /* get the data */
    ret = url_readbuf(rt->rtsp_hd, buf, len);
    if (ret != len)
        return -1;

    /* find the matching stream */
    for(i = 0; i < rt->nb_rtsp_streams; i++) {
        rtsp_st = rt->rtsp_streams[i];
        if (id >= rtsp_st->interleaved_min &&
            id <= rtsp_st->interleaved_max)
            goto found;
    }
    goto redo;