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RTC: Merge srs_rtp_seq_distance with srs_seq_is_newer

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忘篱 2020-05-17 09:03:40 +08:00
parent 3f5ab8dc63
commit d603b1580e
5 changed files with 76 additions and 85 deletions
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2
trunk/src/kernel/srs_kernel_rtc_rtcp.hpp
View file

@ -61,7 +61,7 @@ struct SrsRtcpHeader
struct SrsSeqCompareLess {
bool operator()(const uint16_t &lhs, const uint16_t &rhs) const {
return SrsSeqIsNewer(rhs, lhs);
return srs_seq_is_newer(rhs, lhs);
}
};

48
trunk/src/kernel/srs_kernel_rtc_rtp.cpp
View file

@ -33,54 +33,24 @@ using namespace std;
#include <srs_kernel_utility.hpp>
#include <srs_kernel_flv.hpp>
//sn comparison，if current_sn is more(newer) than last_sn，return true，else return false
bool SrsSeqIsNewer(uint16_t current_sn, uint16_t last_sn) {
if(current_sn > last_sn) {
//current_sn 65533 last_sn 5
if(current_sn - last_sn > 0x8000) {
return false;
} else {
return true;
}
} else {
//current_sn 2 last_sn 65535
if(current_sn - last_sn < -0x8000) {
return true;
} else {
return false;
}
}
// If value is newer than pre_value，return true; otherwise false
bool srs_seq_is_newer(uint16_t value, uint16_t pre_value) {
return srs_rtp_seq_distance(pre_value, value) > 0;
}
bool SrsSeqIsRoolback(uint16_t current_sn, uint16_t last_sn)
bool srs_seq_is_roolback(uint16_t value, uint16_t pre_value)
{
if(SrsSeqIsNewer(current_sn, last_sn)) {
if((last_sn > current_sn)) {
if(srs_seq_is_newer(value, pre_value)) {
if((pre_value > value)) {
return true;
}
}
return false;
}
// caculate the difference between sn. If current_sn is more then last_sn, return positive difference, else return negative difference.
int32_t SrsSeqDistance(uint16_t current_sn, uint16_t last_sn) {
if(current_sn > last_sn) {
//current_sn 65535 last_sn 0
if(current_sn - last_sn > 0x8000) {
return (current_sn - last_sn - 1 - 65535);
} else {
return (current_sn - last_sn);
}
} else {
//current_sn 0 last_sn 65535
if(current_sn - last_sn < -0x8000) {
return (current_sn - last_sn + 65535 + 1);
} else {
return (current_sn - last_sn);
// current_sn 15039 last_sn 15042
//return last_sn - current_sn;
}
}
// If value is newer then pre_value, return positive, otherwise negative.
int32_t srs_seq_distance(uint16_t value, uint16_t pre_value) {
return srs_rtp_seq_distance(pre_value, value);
}
SrsRtpHeader::SrsRtpHeader()

21
trunk/src/kernel/srs_kernel_rtc_rtp.hpp
View file

@ -58,11 +58,22 @@ class SrsRtpRawPayload;
class SrsRtpFUAPayload2;
class SrsSharedPtrMessage;
// TODO: FIXME: Merge with srs_rtp_seq_distance
// @see https://mp.weixin.qq.com/s/JZTInmlB9FUWXBQw_7NYqg
bool SrsSeqIsNewer(uint16_t current_sn, uint16_t last_sn);
bool SrsSeqIsRoolback(uint16_t current_sn, uint16_t last_sn);
int32_t SrsSeqDistance(uint16_t current_sn, uint16_t last_sn);
// The "distance" between two uint16 number, for example:
// distance(prev_value=3, value=5) === (int16_t)(uint16_t)((uint16_t)3-(uint16_t)5) === -2
// distance(prev_value=3, value=65534) === (int16_t)(uint16_t)((uint16_t)3-(uint16_t)65534) === 5
// distance(prev_value=65532, value=65534) === (int16_t)(uint16_t)((uint16_t)65532-(uint16_t)65534) === -2
// For RTP sequence, it's only uint16 and may flip back, so 3 maybe 3+0xffff.
// @remark Note that srs_rtp_seq_distance(0, 32768)>0 is TRUE by https://mp.weixin.qq.com/s/JZTInmlB9FUWXBQw_7NYqg
// but for WebRTC jitter buffer it's FALSE and we follow it.
// @remark For srs_rtp_seq_distance(32768, 0)>0, it's FALSE definitely.
inline int16_t srs_rtp_seq_distance(const uint16_t& prev_value, const uint16_t& value)
{
return (int16_t)(value - prev_value);
}
bool srs_seq_is_newer(uint16_t value, uint16_t pre_value);
bool srs_seq_is_roolback(uint16_t value, uint16_t pre_value);
int32_t srs_seq_distance(uint16_t value, uint16_t pre_value);
class SrsRtpHeader
{