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uvgrtp-base
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Calculate RTP timestamp properly 

Generating NTP and random RTP timestamp allows us to sync different
media streams and provide useful RTP timestamps for RTCP Sender Reports
This commit is contained in:
Aaro Altonen 2019-06-26 12:32:08 +03:00
parent 00bca33585
commit f19fdbda7b
2 changed files with 10 additions and 1 deletions
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9
src/conn.cc
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@ -147,11 +147,18 @@ void kvz_rtp::connection::fill_rtp_header(uint8_t *buffer, uint32_t timestamp)
if (!buffer)
return;
/* This is the first RTP message, get wall clock reading (t = 0)
* and generate random RTP timestamp for this reading */
if (wc_start_ == 0) {
rtp_timestamp_ = generate_rand_32();
wc_start_ = tv_to_ntp();
}
buffer[0] = 2 << 6; // RTP version
buffer[1] = (rtp_payload_ & 0x7f) | (0 << 7);
*(uint16_t *)&buffer[2] = htons(rtp_sequence_);
*(uint32_t *)&buffer[4] = htonl(timestamp);
*(uint32_t *)&buffer[4] = htonl(rtp_timestamp_ + (ntp_diff_ms(tv_to_ntp(), wc_start_)) * clock_rate_ / 1000);
*(uint32_t *)&buffer[8] = htonl(rtp_ssrc_);
}

2
src/conn.hh
View File

@ -87,6 +87,8 @@ namespace kvz_rtp {
uint16_t rtp_sequence_;
uint8_t rtp_payload_;
uint32_t rtp_ssrc_;
uint32_t rtp_timestamp_;
uint64_t wc_start_;
uint32_t clock_rate_;
};
};