+GstClockTime
+rtp_jitter_buffer_calculate_pts (RTPJitterBuffer * jbuf, GstClockTime dts,
+ gboolean estimated_dts, guint32 rtptime, GstClockTime base_time,
+ gint gap, gboolean is_rtx)
+{
+ guint64 ext_rtptime;
+ GstClockTime gstrtptime, pts;
+ GstClock *media_clock, *pipeline_clock;
+ guint64 media_clock_offset;
+ gboolean rfc7273_mode;
+
+ /* rtp time jumps are checked for during skew calculation, but bypassed
+ * in other mode, so mind those here and reset jb if needed.
+ * Only reset if valid input time, which is likely for UDP input
+ * where we expect this might happen due to async thread effects
+ * (in seek and state change cycles), but not so much for TCP input */
+ if (GST_CLOCK_TIME_IS_VALID (dts) && !estimated_dts &&
+ jbuf->mode != RTP_JITTER_BUFFER_MODE_SLAVE &&
+ jbuf->base_time != -1 && jbuf->last_rtptime != -1) {
+ GstClockTime ext_rtptime = jbuf->ext_rtptime;
+
+ ext_rtptime = gst_rtp_buffer_ext_timestamp (&ext_rtptime, rtptime);
+ if (ext_rtptime > jbuf->last_rtptime + 3 * jbuf->clock_rate ||
+ ext_rtptime + 3 * jbuf->clock_rate < jbuf->last_rtptime) {
+ if (!is_rtx) {
+ /* reset even if we don't have valid incoming time;
+ * still better than producing possibly very bogus output timestamp */
+ GST_WARNING ("rtp delta too big, reset skew");
+ rtp_jitter_buffer_reset_skew (jbuf);
+ } else {
+ GST_WARNING ("rtp delta too big: ignore rtx packet");
+ media_clock = NULL;
+ pipeline_clock = NULL;
+ pts = GST_CLOCK_TIME_NONE;
+ goto done;
+ }
+ }
+ }
+
+ /* Return the last time if we got the same RTP timestamp again */
+ ext_rtptime = gst_rtp_buffer_ext_timestamp (&jbuf->ext_rtptime, rtptime);
+ if (jbuf->last_rtptime != -1 && ext_rtptime == jbuf->last_rtptime) {
+ return jbuf->prev_out_time;
+ }
+
+ /* keep track of the last extended rtptime */
+ jbuf->last_rtptime = ext_rtptime;
+
+ g_mutex_lock (&jbuf->clock_lock);
+ media_clock = jbuf->media_clock ? gst_object_ref (jbuf->media_clock) : NULL;
+ pipeline_clock =
+ jbuf->pipeline_clock ? gst_object_ref (jbuf->pipeline_clock) : NULL;
+ media_clock_offset = jbuf->media_clock_offset;
+ g_mutex_unlock (&jbuf->clock_lock);
+
+ gstrtptime =
+ gst_util_uint64_scale_int (ext_rtptime, GST_SECOND, jbuf->clock_rate);
+
+ if (G_LIKELY (jbuf->base_rtptime != -1)) {
+ /* check elapsed time in RTP units */
+ if (gstrtptime < jbuf->base_rtptime) {
+ if (!is_rtx) {
+ /* elapsed time at sender, timestamps can go backwards and thus be
+ * smaller than our base time, schedule to take a new base time in
+ * that case. */
+ GST_WARNING ("backward timestamps at server, schedule resync");
+ jbuf->need_resync = TRUE;
+ } else {
+ GST_WARNING ("backward timestamps: ignore rtx packet");
+ pts = GST_CLOCK_TIME_NONE;
+ goto done;
+ }
+ }
+ }
+
+ switch (jbuf->mode) {
+ case RTP_JITTER_BUFFER_MODE_NONE:
+ case RTP_JITTER_BUFFER_MODE_BUFFER:
+ /* send 0 as the first timestamp and -1 for the other ones. This will
+ * interpolate them from the RTP timestamps with a 0 origin. In buffering
+ * mode we will adjust the outgoing timestamps according to the amount of
+ * time we spent buffering. */
+ if (jbuf->base_time == -1)
+ dts = 0;
+ else
+ dts = -1;
+ break;
+ case RTP_JITTER_BUFFER_MODE_SYNCED:
+ /* synchronized clocks, take first timestamp as base, use RTP timestamps
+ * to interpolate */
+ if (jbuf->base_time != -1 && !jbuf->need_resync)
+ dts = -1;
+ break;
+ case RTP_JITTER_BUFFER_MODE_SLAVE:
+ default:
+ break;
+ }
+
+ /* need resync, lock on to time and gstrtptime if we can, otherwise we
+ * do with the previous values */
+ if (G_UNLIKELY (jbuf->need_resync && dts != -1)) {
+ if (is_rtx) {
+ GST_DEBUG ("not resyncing on rtx packet, discard");
+ pts = GST_CLOCK_TIME_NONE;
+ goto done;
+ }
+ GST_INFO ("resync to time %" GST_TIME_FORMAT ", rtptime %"
+ GST_TIME_FORMAT, GST_TIME_ARGS (dts), GST_TIME_ARGS (gstrtptime));
+ rtp_jitter_buffer_resync (jbuf, dts, gstrtptime, ext_rtptime, FALSE);
+ }
+
+ GST_DEBUG ("extrtp %" G_GUINT64_FORMAT ", gstrtp %" GST_TIME_FORMAT ", base %"
+ GST_TIME_FORMAT ", send_diff %" GST_TIME_FORMAT, ext_rtptime,
+ GST_TIME_ARGS (gstrtptime), GST_TIME_ARGS (jbuf->base_rtptime),
+ GST_TIME_ARGS (gstrtptime - jbuf->base_rtptime));
+
+ rfc7273_mode = media_clock && pipeline_clock
+ && gst_clock_is_synced (media_clock);
+
+ if (rfc7273_mode && jbuf->mode == RTP_JITTER_BUFFER_MODE_SLAVE
+ && (media_clock_offset == -1 || !jbuf->rfc7273_sync)) {
+ GstClockTime internal, external;
+ GstClockTime rate_num, rate_denom;
+ GstClockTime nsrtptimediff, rtpntptime, rtpsystime;
+
+ gst_clock_get_calibration (media_clock, &internal, &external, &rate_num,
+ &rate_denom);
+
+ /* Slave to the RFC7273 media clock instead of trying to estimate it
+ * based on receive times and RTP timestamps */
+
+ if (jbuf->media_clock_base_time == -1) {
+ if (jbuf->base_time != -1) {
+ jbuf->media_clock_base_time =
+ gst_clock_unadjust_with_calibration (media_clock,
+ jbuf->base_time + base_time, internal, external, rate_num,
+ rate_denom);
+ } else {
+ if (dts != -1)
+ jbuf->media_clock_base_time =
+ gst_clock_unadjust_with_calibration (media_clock, dts + base_time,
+ internal, external, rate_num, rate_denom);
+ else
+ jbuf->media_clock_base_time =
+ gst_clock_get_internal_time (media_clock);
+ jbuf->base_rtptime = gstrtptime;
+ }
+ }
+
+ if (gstrtptime > jbuf->base_rtptime)
+ nsrtptimediff = gstrtptime - jbuf->base_rtptime;
+ else
+ nsrtptimediff = 0;
+
+ rtpntptime = nsrtptimediff + jbuf->media_clock_base_time;
+
+ rtpsystime =
+ gst_clock_adjust_with_calibration (media_clock, rtpntptime, internal,
+ external, rate_num, rate_denom);
+
+ if (rtpsystime > base_time)
+ pts = rtpsystime - base_time;
+ else
+ pts = 0;
+
+ GST_DEBUG ("RFC7273 clock time %" GST_TIME_FORMAT ", out %" GST_TIME_FORMAT,
+ GST_TIME_ARGS (rtpsystime), GST_TIME_ARGS (pts));
+ } else if (rfc7273_mode && (jbuf->mode == RTP_JITTER_BUFFER_MODE_SLAVE
+ || jbuf->mode == RTP_JITTER_BUFFER_MODE_SYNCED)
+ && media_clock_offset != -1 && jbuf->rfc7273_sync) {
+ GstClockTime ntptime, rtptime_tmp;
+ GstClockTime ntprtptime, rtpsystime;
+ GstClockTime internal, external;
+ GstClockTime rate_num, rate_denom;
+
+ /* Don't do any of the dts related adjustments further down */
+ dts = -1;
+
+ /* Calculate the actual clock time on the sender side based on the
+ * RFC7273 clock and convert it to our pipeline clock
+ */
+
+ gst_clock_get_calibration (media_clock, &internal, &external, &rate_num,
+ &rate_denom);
+
+ ntptime = gst_clock_get_internal_time (media_clock);
+
+ ntprtptime = gst_util_uint64_scale (ntptime, jbuf->clock_rate, GST_SECOND);
+ ntprtptime += media_clock_offset;
+ ntprtptime &= 0xffffffff;
+
+ rtptime_tmp = rtptime;
+ /* Check for wraparounds, we assume that the diff between current RTP
+ * timestamp and current media clock time can't be bigger than
+ * 2**31 clock units */
+ if (ntprtptime > rtptime_tmp && ntprtptime - rtptime_tmp >= 0x80000000)
+ rtptime_tmp += G_GUINT64_CONSTANT (0x100000000);
+ else if (rtptime_tmp > ntprtptime && rtptime_tmp - ntprtptime >= 0x80000000)
+ ntprtptime += G_GUINT64_CONSTANT (0x100000000);
+
+ if (ntprtptime > rtptime_tmp)
+ ntptime -=
+ gst_util_uint64_scale (ntprtptime - rtptime_tmp, GST_SECOND,
+ jbuf->clock_rate);
+ else
+ ntptime +=
+ gst_util_uint64_scale (rtptime_tmp - ntprtptime, GST_SECOND,
+ jbuf->clock_rate);
+
+ rtpsystime =
+ gst_clock_adjust_with_calibration (media_clock, ntptime, internal,
+ external, rate_num, rate_denom);
+ /* All this assumes that the pipeline has enough additional
+ * latency to cover for the network delay */
+ if (rtpsystime > base_time)
+ pts = rtpsystime - base_time;
+ else
+ pts = 0;
+
+ GST_DEBUG ("RFC7273 clock time %" GST_TIME_FORMAT ", out %" GST_TIME_FORMAT,
+ GST_TIME_ARGS (rtpsystime), GST_TIME_ARGS (pts));
+ } else {
+ /* If we used the RFC7273 clock before and not anymore,
+ * we need to resync it later again */
+ jbuf->media_clock_base_time = -1;
+
+ /* do skew calculation by measuring the difference between rtptime and the
+ * receive dts, this function will return the skew corrected rtptime. */
+ pts = calculate_skew (jbuf, ext_rtptime, gstrtptime, dts, gap, is_rtx);
+ }
+
+ /* check if timestamps are not going backwards, we can only check this if we
+ * have a previous out time and a previous send_diff */
+ if (G_LIKELY (pts != -1 && jbuf->prev_out_time != -1
+ && jbuf->prev_send_diff != -1)) {
+ /* now check for backwards timestamps */
+ if (G_UNLIKELY (
+ /* if the server timestamps went up and the out_time backwards */
+ (gstrtptime - jbuf->base_rtptime > jbuf->prev_send_diff
+ && pts < jbuf->prev_out_time) ||
+ /* if the server timestamps went backwards and the out_time forwards */
+ (gstrtptime - jbuf->base_rtptime < jbuf->prev_send_diff
+ && pts > jbuf->prev_out_time) ||
+ /* if the server timestamps did not change */
+ gstrtptime - jbuf->base_rtptime == jbuf->prev_send_diff)) {
+ GST_DEBUG ("backwards timestamps, using previous time");
+ pts = jbuf->prev_out_time;
+ }
+ }
+
+ if (gap == 0 && dts != -1 && pts + jbuf->delay < dts) {
+ /* if we are going to produce a timestamp that is later than the input
+ * timestamp, we need to reset the jitterbuffer. Likely the server paused
+ * temporarily */
+ GST_DEBUG ("out %" GST_TIME_FORMAT " + %" G_GUINT64_FORMAT " < time %"
+ GST_TIME_FORMAT ", reset jitterbuffer and discard", GST_TIME_ARGS (pts),
+ jbuf->delay, GST_TIME_ARGS (dts));
+ rtp_jitter_buffer_reset_skew (jbuf);
+ rtp_jitter_buffer_resync (jbuf, dts, gstrtptime, ext_rtptime, TRUE);
+ pts = dts;
+ }
+
+ jbuf->prev_out_time = pts;
+ jbuf->prev_send_diff = gstrtptime - jbuf->base_rtptime;
+
+done:
+ if (media_clock)
+ gst_object_unref (media_clock);
+ if (pipeline_clock)
+ gst_object_unref (pipeline_clock);
+
+ return pts;
+}
+
+