rtpjitterbuffer: make sure not to drop packets based on skew

One of the jitterbuffers functions is to try and make sense of weird
network behavior.

It is quite unhelpful for the jitterbuffer to start dropping packets
itself when what you are trying to achieve is better network resilience.

In the case of a skew, this could often mean the sender has restarted
in some fashion, and then dropping the very first buffer of this "new"
stream could often mean missing valuable information, like in the case
of video and I-frames.

This patch simply reverts back to the old behavior, prior to 8d955fc32b
and includes the simplest test I could write to demonstrate the behavior,
where a single packet arrives "perfectly", then a 50ms gap happens,
and then two more packets arrive in perfect order after that.

# Conflicts:
#	tests/check/elements/rtpjitterbuffer.c
This commit is contained in:
Havard Graff 2019-10-20 12:17:25 +02:00 committed by GStreamer Merge Bot
parent a195d5a4a6
commit 87457a862d
2 changed files with 36 additions and 2 deletions

View file

@ -955,8 +955,8 @@ rtp_jitter_buffer_calculate_pts (RTPJitterBuffer * jbuf, GstClockTime dts,
GST_TIME_FORMAT ", reset jitterbuffer and discard", GST_TIME_ARGS (pts),
jbuf->delay, GST_TIME_ARGS (dts));
rtp_jitter_buffer_reset_skew (jbuf);
pts = GST_CLOCK_TIME_NONE;
goto done;
rtp_jitter_buffer_resync (jbuf, dts, gstrtptime, ext_rtptime, TRUE);
pts = dts;
}
jbuf->prev_out_time = pts;

View file

@ -2729,6 +2729,39 @@ GST_START_TEST (test_rtx_does_not_affect_pts_calculation)
GST_END_TEST;
GST_START_TEST (test_dont_drop_packet_based_on_skew)
{
GstHarness *h = gst_harness_new ("rtpjitterbuffer");
guint base_seqnum;
GstClockTime now;
guint i;
/* set up a deterministic state and take the time on the clock */
g_object_set (h->element, "do-retransmission", TRUE, "do-lost", TRUE, NULL);
base_seqnum = construct_deterministic_initial_state (h, 20);
now = gst_clock_get_time (GST_ELEMENT_CLOCK (h->element));
/* and after a delay of 50ms... */
now += GST_MSECOND * 50;
gst_test_clock_set_time (GST_TEST_CLOCK (GST_ELEMENT_CLOCK (h->element)),
now);
/* ..two more buffers arrive in perfect order */
for (i = 0; i < 2; i++) {
gst_harness_push (h, generate_test_buffer_full (now + i * GST_MSECOND * 20,
base_seqnum + i, (base_seqnum + i) * TEST_RTP_TS_DURATION));
}
/* verify we did not drop any of them */
for (i = 0; i < 2; i++) {
gst_buffer_unref (gst_harness_pull (h));
}
gst_harness_teardown (h);
}
GST_END_TEST;
GST_START_TEST (test_timer_queue_set_timer)
{
RtpTimerQueue *queue = rtp_timer_queue_new ();
@ -3364,6 +3397,7 @@ rtpjitterbuffer_suite (void)
tcase_add_test (tc_chain, test_minor_reorder_does_not_skew);
tcase_add_loop_test (tc_chain, test_rtx_does_not_affect_pts_calculation, 0,
G_N_ELEMENTS (rtx_does_not_affect_pts_calculation_input));
tcase_add_test (tc_chain, test_dont_drop_packet_based_on_skew);
tcase_add_test (tc_chain, test_deadline_ts_offset);
tcase_add_test (tc_chain, test_big_gap_seqnum);