Question #661623 on rohc changed:
https://answers.launchpad.net/rohc/+question/661623
regulararmy posted a new comment:
I modify the code in the RTP callback,it shows as follows:
uint8_t count = 0;
uint32_t ssrc[4] = {0};
static bool rtp_detect_cb(const unsigned char *const ip,
const unsigned char *const udp,
const unsigned char *const payload,
const unsigned int payload_size,
void *const rtp_private)
{
const uint16_t max_well_known_port = 1024;
const uint16_t sip_port = 5060;
uint16_t udp_sport;
uint16_t udp_dport;
uint16_t udp_len;
uint8_t rtp_pt;
uint32_t currentSsrc ;
bool is_rtp = false;
assert(ip != NULL);
assert(udp != NULL);
assert(payload != NULL);
assert(rtp_private == NULL);
/* retrieve UDP source and destination ports and UDP length */
memcpy(&udp_sport, udp, sizeof(uint16_t));
memcpy(&udp_dport, udp + 2, sizeof(uint16_t));
memcpy(&udp_len, udp + 4, sizeof(uint16_t));
/* RTP streams do not use well known ports */
if(ntohs(udp_sport) <= max_well_known_port ||
ntohs(udp_dport) <= max_well_known_port)
{
goto not_rtp;
}
/* SIP (UDP/5060) is not RTP */
if(ntohs(udp_sport) == sip_port && ntohs(udp_dport) == sip_port)
{
goto not_rtp;
}
/* the UDP destination port of RTP packet is even (the RTCP destination
* port are RTP destination port + 1, so it is odd) */
if((ntohs(udp_dport) % 2) != 0)
{
goto not_rtp;
}
/* UDP Length shall not be too large */
if(ntohs(udp_len) > 200)
{
goto not_rtp;
}
/* UDP payload shall at least contain the smallest RTP header */
if(payload_size < 12)
{
goto not_rtp;
}
/* RTP version bits shall be 2 */
if(((payload[0] >> 6) & 0x3) != 0x2)
{
goto not_rtp;
}
/* RTP payload type shall be GSM (0x03), ITU-T G.723 (0x04),
* ITU-T G.729 (0x12), dynamic RTP type 97 (0x61),
* telephony-event (0x65), Speex (0x72),
* or dynamic RTP type 125 (0x7d) */
rtp_pt = payload[1] & 0x7f;
if(rtp_pt != 0x03 && rtp_pt != 0x04 && rtp_pt != 0x12 && rtp_pt != 0x61
&&
rtp_pt != 0x65 && rtp_pt != 0x72 && rtp_pt != 0x7d)
{
goto not_rtp;
}
memcpy(¤tSsrc, payload + 8, sizeof(uint32_t));
if(ssrc[0] != ntohl(currentSsrc) || ssrc[1] != ntohl(currentSsrc)||ssrc[2]
!= ntohl(currentSsrc) || ssrc[3] != ntohl(currentSsrc))
{
ssrc[count++ & 0x03] = ntohl(currentSsrc);
goto not_rtp;
}
/* we think that the UDP packet is a RTP packet */
is_rtp = true;
not_rtp:
return is_rtp;
}
--
You received this question notification because your team ROHC Team is
an answer contact for rohc.
_______________________________________________
Mailing list: https://launchpad.net/~rohc
Post to : [email protected]
Unsubscribe : https://launchpad.net/~rohc
More help : https://help.launchpad.net/ListHelp
