srs中时间戳抖动处理

/*** the time jitter algorithm:* 1. full, to ensure stream start at zero, and ensure stream monotonically increasing.* 2. zero, only ensure sttream start at zero, ignore timestamp jitter.* 3. off, disable the time jitter algorithm, like atc.*/enum SrsRtmpJitterAlgorithm{    SrsRtmpJitterAlgorithmFULL = 0x01,    SrsRtmpJitterAlgorithmZERO,    SrsRtmpJitterAlgorithmOFF};int _srs_time_jitter_string2int(std::string time_jitter);/*** time jitter detect and correct,* to ensure the rtmp stream is monotonically.*/class SrsRtmpJitter{private:    int64_t last_pkt_time;    int64_t last_pkt_correct_time;public:    SrsRtmpJitter();    virtual ~SrsRtmpJitter();public:    /**    * detect the time jitter and correct it.    * @param tba, the audio timebase, used to calc the "right" delta if jitter detected.    * @param tbv, the video timebase, used to calc the "right" delta if jitter detected.    * @param start_at_zero whether ensure stream start at zero.    * @param mono_increasing whether ensure stream is monotonically inscreasing.    */    virtual int correct(SrsSharedPtrMessage* msg, int tba, int tbv, SrsRtmpJitterAlgorithm ag);    /**    * get current client time, the last packet time.    */    virtual int get_time();};

超过抖动区域，置为默认值，都是相对时间

#define CONST_MAX_JITTER_MS         250#define CONST_MAX_JITTER_MS_NEG         -250#define DEFAULT_FRAME_TIME_MS         10// for 26ms per audio packet,// 115 packets is 3s.#define SRS_PURE_AUDIO_GUESS_COUNT 115// when got these videos or audios, pure audio or video, mix ok.#define SRS_MIX_CORRECT_PURE_AV 10// the time to cleanup source in ms.#define SRS_SOURCE_CLEANUP 30000int _srs_time_jitter_string2int(std::string time_jitter){    if (time_jitter == "full") {        return SrsRtmpJitterAlgorithmFULL;    } else if (time_jitter == "zero") {        return SrsRtmpJitterAlgorithmZERO;    } else {        return SrsRtmpJitterAlgorithmOFF;    }}SrsRtmpJitter::SrsRtmpJitter(){    last_pkt_correct_time = -1;    last_pkt_time = 0;}SrsRtmpJitter::~SrsRtmpJitter(){}int SrsRtmpJitter::correct(SrsSharedPtrMessage* msg, SrsRtmpJitterAlgorithm ag){    int ret = ERROR_SUCCESS;        // for performance issue    if (ag != SrsRtmpJitterAlgorithmFULL) {        // all jitter correct features is disabled, ignore.        if (ag == SrsRtmpJitterAlgorithmOFF) {            return ret;        }            // start at zero, but donot ensure monotonically increasing.        if (ag == SrsRtmpJitterAlgorithmZERO) {            // for the first time, last_pkt_correct_time is -1.            if (last_pkt_correct_time == -1) {                last_pkt_correct_time = msg->timestamp;            }            msg->timestamp -= last_pkt_correct_time;            return ret;        }                // other algorithm, ignore.        return ret;    }        // full jitter algorithm, do jitter correct.    // set to 0 for metadata.    if (!msg->is_av()) {        msg->timestamp = 0;        return ret;    }        /**    * we use a very simple time jitter detect/correct algorithm:    * 1. delta: ensure the delta is positive and valid,    *     we set the delta to DEFAULT_FRAME_TIME_MS,    *     if the delta of time is nagative or greater than CONST_MAX_JITTER_MS.    * 2. last_pkt_time: specifies the original packet time,    *     is used to detect next jitter.    * 3. last_pkt_correct_time: simply add the positive delta,     *     and enforce the time monotonically.    */    int64_t time = msg->timestamp;    int64_t delta = time - last_pkt_time;    // if jitter detected, reset the delta.    if (delta < CONST_MAX_JITTER_MS_NEG || delta > CONST_MAX_JITTER_MS) {        // use default 10ms to notice the problem of stream.        // @see https://github.com/ossrs/srs/issues/425        delta = DEFAULT_FRAME_TIME_MS;                srs_info("jitter detected, last_pts=%"PRId64", pts=%"PRId64", diff=%"PRId64", last_time=%"PRId64", time=%"PRId64", diff=%"PRId64"",            last_pkt_time, time, time - last_pkt_time, last_pkt_correct_time, last_pkt_correct_time + delta, delta);    } else {        srs_verbose("timestamp no jitter. time=%"PRId64", last_pkt=%"PRId64", correct_to=%"PRId64"",             time, last_pkt_time, last_pkt_correct_time + delta);    }        last_pkt_correct_time = srs_max(0, last_pkt_correct_time + delta);        msg->timestamp = last_pkt_correct_time;    last_pkt_time = time;        return ret;}int SrsRtmpJitter::get_time(){    return (int)last_pkt_correct_time;}