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jitterbuffer: reorganize timer handling

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Restructure handling of incomming packet and the gap with the expected seqnum
and register all timers from the _chain function.
Convert a timer to a LOST packet timer when the max amount of retransmission
requests has been reached.
This commit is contained in:
Wim Taymans 2013-08-19 21:10:00 +02:00
parent d9d6eac4bb
commit a88db5fa2c
1 changed files with 92 additions and 77 deletions
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169
gst/rtpmanager/gstrtpjitterbuffer.c
View file

@ -1599,19 +1599,13 @@ update_timers (GstRtpJitterBuffer * jitterbuffer, guint16 seqnum,
GST_DEBUG_OBJECT (jitterbuffer, "%d, #%d<->#%d gap %d", i,
test->seqnum, seqnum, gap);
if (test->type == TIMER_TYPE_LOST) {
if (gap == 0) {
remove_timer (jitterbuffer, test);
len--;
i--;
}
continue;
} else if (test->type != TIMER_TYPE_EXPECTED)
if (test->type == TIMER_TYPE_DEADLINE)
continue;
if (gap == 0) {
/* the timer for the current seqnum */
timer = test;
break;
} else if (gap > priv->rtx_delay_reorder) {
/* max gap, we exceeded the max reorder distance and we don't expect the
* missing packet to be this reordered */
@ -1659,6 +1653,47 @@ calculate_packet_spacing (GstRtpJitterBuffer * jitterbuffer, guint32 rtptime,
}
}
static void
calculate_expected (GstRtpJitterBuffer * jitterbuffer, guint32 expected,
guint16 seqnum, GstClockTime dts, gint gap)
{
GstRtpJitterBufferPrivate *priv = jitterbuffer->priv;
GstClockTime duration, expected_dts;
TimerType type;
GST_DEBUG_OBJECT (jitterbuffer,
"dts %" GST_TIME_FORMAT ", last %" GST_TIME_FORMAT,
GST_TIME_ARGS (dts), GST_TIME_ARGS (priv->last_in_dts));
/* interpolate between the current time and the last time based on
* number of packets we are missing, this is the estimated duration
* for the missing packet based on equidistant packet spacing. Also make
* sure we never go negative. */
if (dts >= priv->last_in_dts)
duration = (dts - priv->last_in_dts) / (gap + 1);
else
/* packet already lost, timer will timeout quickly */
duration = 0;
GST_DEBUG_OBJECT (jitterbuffer, "duration %" GST_TIME_FORMAT,
GST_TIME_ARGS (duration));
expected_dts = priv->last_in_dts + duration;
if (priv->do_retransmission) {
expected++;
type = TIMER_TYPE_EXPECTED;
} else {
type = TIMER_TYPE_LOST;
}
while (expected < seqnum) {
add_timer (jitterbuffer, type, expected, expected_dts);
expected_dts += duration;
expected++;
}
}
static GstFlowReturn
gst_rtp_jitter_buffer_chain (GstPad * pad, GstObject * parent,
GstBuffer * buffer)
@ -1747,27 +1782,42 @@ gst_rtp_jitter_buffer_chain (GstPad * pad, GstObject * parent,
if (G_LIKELY (expected != -1)) {
gint gap;
/* now calculate gap */
gap = gst_rtp_buffer_compare_seqnum (expected, seqnum);
if (G_UNLIKELY (gap != 0)) {
GST_DEBUG_OBJECT (jitterbuffer, "expected #%d, got #%d, gap of %d",
expected, seqnum, gap);
if (G_LIKELY (gap == 0)) {
/* packet is expected */
calculate_packet_spacing (jitterbuffer, rtptime, dts);
do_next_seqnum = TRUE;
} else {
gboolean reset = FALSE;
GST_DEBUG_OBJECT (jitterbuffer, "expected #%d, got #%d, gap of %d",
expected, seqnum, gap);
/* expected >= seqnum, this packet is too late or the
* sender might have been restarted with different seqnum. */
if (gap < -RTP_MAX_MISORDER) {
GST_DEBUG_OBJECT (jitterbuffer, "reset: buffer too old %d", gap);
reset = TRUE;
}
/* expected < seqnum, this is a new packet */
else if (G_UNLIKELY (gap > RTP_MAX_DROPOUT)) {
GST_DEBUG_OBJECT (jitterbuffer, "reset: too many dropped packets %d",
gap);
reset = TRUE;
if (gap < 0) {
/* we received an old packet */
if (G_UNLIKELY (gap < -RTP_MAX_MISORDER)) {
/* too old packet, reset */
GST_DEBUG_OBJECT (jitterbuffer, "reset: buffer too old %d < %d", gap,
-RTP_MAX_MISORDER);
reset = TRUE;
} else {
GST_DEBUG_OBJECT (jitterbuffer, "old packet received");
}
} else {
GST_DEBUG_OBJECT (jitterbuffer, "tolerable gap");
if (gap > 0)
/* new packet, we are missing some packets */
if (G_UNLIKELY (gap > RTP_MAX_DROPOUT)) {
/* packet too far in future, reset */
GST_DEBUG_OBJECT (jitterbuffer, "reset: buffer too new %d > %d", gap,
RTP_MAX_DROPOUT);
reset = TRUE;
} else {
GST_DEBUG_OBJECT (jitterbuffer, "%d missing packets", gap);
/* fill in the gap with EXPECTED timers */
calculate_expected (jitterbuffer, expected, seqnum, dts, gap);
do_next_seqnum = TRUE;
}
}
if (G_UNLIKELY (reset)) {
GST_DEBUG_OBJECT (jitterbuffer, "flush and reset jitterbuffer");
@ -1781,13 +1831,13 @@ gst_rtp_jitter_buffer_chain (GstPad * pad, GstObject * parent,
/* reset spacing estimation when gap */
priv->ips_rtptime = -1;
priv->ips_dts = GST_CLOCK_TIME_NONE;
} else {
/* packet is expected */
calculate_packet_spacing (jitterbuffer, rtptime, dts);
do_next_seqnum = TRUE;
}
} else {
/* unknow first seqnum */
GST_DEBUG_OBJECT (jitterbuffer, "First buffer #%d", seqnum);
/* we don't know what the next_in_seqnum should be, wait for the last
* possible moment to push this buffer, maybe we get an earlier seqnum
* while we wait */
set_timer (jitterbuffer, TIMER_TYPE_DEADLINE, seqnum, dts);
do_next_seqnum = TRUE;
}
if (do_next_seqnum) {
@ -1828,6 +1878,7 @@ gst_rtp_jitter_buffer_chain (GstPad * pad, GstObject * parent,
}
}
/* we need to make the metadata writable before pushing it in the jitterbuffer
* because the jitterbuffer will update the PTS */
buffer = gst_buffer_make_writable (buffer);
@ -2064,38 +2115,6 @@ out_flushing:
}
}
static GstClockTime
estimate_dts (GstRtpJitterBuffer * jitterbuffer, GstClockTime dts, gint gap)
{
GstRtpJitterBufferPrivate *priv = jitterbuffer->priv;
GstClockTime duration;
if (dts == -1 || priv->last_out_dts == -1)
return dts;
GST_DEBUG_OBJECT (jitterbuffer,
"dts %" GST_TIME_FORMAT ", last %" GST_TIME_FORMAT,
GST_TIME_ARGS (dts), GST_TIME_ARGS (priv->last_out_dts));
/* interpolate between the current time and the last time based on
* number of packets we are missing, this is the estimated duration
* for the missing packet based on equidistant packet spacing. Also make
* sure we never go negative. */
if (dts >= priv->last_out_dts)
duration = (dts - priv->last_out_dts) / (gap + 1);
else
/* packet already lost, timer will timeout quickly */
duration = 0;
GST_DEBUG_OBJECT (jitterbuffer, "duration %" GST_TIME_FORMAT,
GST_TIME_ARGS (duration));
/* add this duration to the timestamp of the last packet we pushed */
dts = (priv->last_out_dts + duration);
return dts;
}
#define GST_FLOW_WAIT GST_FLOW_CUSTOM_SUCCESS
/* Peek a buffer and compare the seqnum to the expected seqnum.
@ -2115,7 +2134,6 @@ handle_next_buffer (GstRtpJitterBuffer * jitterbuffer)
GstFlowReturn result = GST_FLOW_OK;
GstBuffer *outbuf;
guint16 seqnum;
GstClockTime dts;
guint32 next_seqnum;
gint gap;
GstRTPBuffer rtp = { NULL, };
@ -2142,16 +2160,13 @@ again:
next_seqnum = priv->next_seqnum;
dts = GST_BUFFER_DTS (outbuf);
/* get the gap between this and the previous packet. If we don't know the
* previous packet seqnum assume no gap. */
if (G_UNLIKELY (next_seqnum == -1)) {
GST_DEBUG_OBJECT (jitterbuffer, "First buffer #%d", seqnum);
/* we don't know what the next_seqnum should be, wait for the last
* possible moment to push this buffer, maybe we get an earlier seqnum
* while we wait */
set_timer (jitterbuffer, TIMER_TYPE_DEADLINE, seqnum, dts);
/* we don't know what the next_seqnum should be, the chain function should
* have scheduled a DEADLINE timer that will increment next_seqnum when it
* fires, so wait for that */
result = GST_FLOW_WAIT;
} else {
/* else calculate GAP */
@ -2172,10 +2187,6 @@ again:
GST_DEBUG_OBJECT (jitterbuffer,
"Sequence number GAP detected: expected %d instead of %d (%d missing)",
next_seqnum, seqnum, gap);
/* packet missing, estimate when we should ultimately push this packet */
dts = estimate_dts (jitterbuffer, dts, gap);
/* and set a timer for it */
set_timer (jitterbuffer, TIMER_TYPE_LOST, next_seqnum, dts);
result = GST_FLOW_WAIT;
}
}
@ -2213,11 +2224,15 @@ do_expected_timeout (GstRtpJitterBuffer * jitterbuffer, TimerData * timer,
JBUF_LOCK (priv);
timer->rtx_retry += (priv->rtx_retry_timeout * GST_MSECOND);
if (timer->rtx_retry > (priv->rtx_retry_period * GST_MSECOND))
remove_timer (jitterbuffer, timer);
else
reschedule_timer (jitterbuffer, timer, timer->seqnum,
timer->rtx_base + timer->rtx_retry);
if (timer->rtx_retry > (priv->rtx_retry_period * GST_MSECOND)) {
GST_DEBUG_OBJECT (jitterbuffer, "reschedule as LOST timer");
/* too many retransmission request, we now convert the timer
* to a lost timer */
timer->type = TIMER_TYPE_LOST;
timer->rtx_retry = 0;
}
reschedule_timer (jitterbuffer, timer, timer->seqnum,
timer->rtx_base + timer->rtx_retry);
return priv->srcresult;
}