gst/rtpmanager/gstrtpjitterbuffer.c: Remove jitter correction code, it's now in the lower level object.

Original commit message from CVS:
* gst/rtpmanager/gstrtpjitterbuffer.c: (apply_latency),
(gst_rtp_jitter_buffer_loop), (gst_rtp_jitter_buffer_query):
Remove jitter correction code, it's now in the lower level object.
Use new -core method for doing a peer query.
* gst/rtpmanager/rtpjitterbuffer.c: (rtp_jitter_buffer_init),
(calculate_skew), (rtp_jitter_buffer_insert):
* gst/rtpmanager/rtpjitterbuffer.h:
Move jitter correction to the lowlevel jitterbuffer.
Increase the max window size.
When filling the window, already start estimating the skew using a
parabolic weighting factor so that we have a much better startup
behaviour that gets more accurate with the more samples we have.
Increase the default weighting factor for the steady state to get
smoother timestamps.
This commit is contained in:
Wim Taymans 2007-09-28 11:17:35 +00:00 committed by Tim-Philipp Müller
parent fa00695a39
commit 2b1f49a26e
3 changed files with 105 additions and 92 deletions

View file

@ -943,25 +943,14 @@ duplicate:
}
static GstClockTime
convert_rtptime_to_gsttime (GstRtpJitterBuffer * jitterbuffer,
guint64 exttimestamp)
apply_latency (GstRtpJitterBuffer * jitterbuffer, GstClockTime timestamp)
{
GstClockTime timestamp;
GstRtpJitterBufferPrivate *priv;
priv = jitterbuffer->priv;
/* construct a timestamp from the RTP timestamp now. We don't apply this
* timestamp to the outgoing buffer yet as the popped buffer might not be the
* one we need to push out right now. */
timestamp =
gst_util_uint64_scale_int (exttimestamp, GST_SECOND, priv->clock_rate);
/* apply first observed timestamp */
timestamp += priv->jbuf->base_time;
/* apply the current clock skew */
timestamp += priv->jbuf->skew;
if (timestamp == -1)
return -1;
/* apply the timestamp offset */
timestamp += priv->ts_offset;
@ -987,9 +976,7 @@ gst_rtp_jitter_buffer_loop (GstRtpJitterBuffer * jitterbuffer)
GstBuffer *outbuf = NULL;
GstFlowReturn result;
guint16 seqnum;
guint32 rtp_time;
GstClockTime timestamp;
guint64 exttimestamp;
GstClockTime timestamp, out_time;
priv = jitterbuffer->priv;
@ -1015,26 +1002,17 @@ again:
outbuf = rtp_jitter_buffer_pop (priv->jbuf);
seqnum = gst_rtp_buffer_get_seq (outbuf);
/* construct extended RTP timestamp from packet */
rtp_time = gst_rtp_buffer_get_timestamp (outbuf);
exttimestamp = gst_rtp_buffer_ext_timestamp (&priv->exttimestamp, rtp_time);
/* if no clock_base was given, take first ts as base */
if (priv->clock_base == -1) {
GST_DEBUG_OBJECT (jitterbuffer,
"no clock base, using exttimestamp %" G_GUINT64_FORMAT, exttimestamp);
priv->clock_base = exttimestamp;
}
/* subtract the base clock time so that we start counting from 0 */
exttimestamp -= priv->clock_base;
/* get the timestamp, this is already corrected for clock skew by the
* jitterbuffer */
timestamp = GST_BUFFER_TIMESTAMP (outbuf);
GST_DEBUG_OBJECT (jitterbuffer,
"Popped buffer #%d, rtptime %u, exttime %" G_GUINT64_FORMAT
", now %d left", seqnum, rtp_time, exttimestamp,
"Popped buffer #%d, timestamp %" GST_TIME_FORMAT ", now %d left",
seqnum, GST_TIME_ARGS (timestamp),
rtp_jitter_buffer_num_packets (priv->jbuf));
/* convert the RTP timestamp to a gstreamer timestamp. */
timestamp = convert_rtptime_to_gsttime (jitterbuffer, exttimestamp);
/* apply our latency to the incomming buffer before syncing. */
out_time = apply_latency (jitterbuffer, timestamp);
/* If we don't know what the next seqnum should be (== -1) we have to wait
* because it might be possible that we are not receiving this buffer in-order,
@ -1044,7 +1022,8 @@ again:
* determine if we have missing a packet. If we have a missing packet (which
* must be before this packet) we can wait for it until the deadline for this
* packet expires. */
if (priv->next_seqnum == -1 || priv->next_seqnum != seqnum) {
if ((priv->next_seqnum == -1 || priv->next_seqnum != seqnum)
&& out_time != -1) {
GstClockID id;
GstClockTime sync_time;
GstClockReturn ret;
@ -1071,10 +1050,10 @@ again:
}
GST_DEBUG_OBJECT (jitterbuffer, "sync to timestamp %" GST_TIME_FORMAT,
GST_TIME_ARGS (timestamp));
GST_TIME_ARGS (out_time));
/* prepare for sync against clock */
sync_time = timestamp + GST_ELEMENT_CAST (jitterbuffer)->base_time;
sync_time = out_time + GST_ELEMENT_CAST (jitterbuffer)->base_time;
/* create an entry for the clock */
id = priv->clock_id = gst_clock_new_single_shot_id (clock, sync_time);
@ -1113,9 +1092,8 @@ again:
}
goto again;
}
/* After waiting, we might have a better estimate of skew, generate a new
* timestamp before pushing out the buffer */
timestamp = convert_rtptime_to_gsttime (jitterbuffer, exttimestamp);
/* Get new timestamp, latency might have changed */
out_time = apply_latency (jitterbuffer, timestamp);
}
push_buffer:
/* check if we are pushing something unexpected */
@ -1138,7 +1116,7 @@ push_buffer:
}
/* apply timestamp to buffer now */
GST_BUFFER_TIMESTAMP (outbuf) = timestamp;
GST_BUFFER_TIMESTAMP (outbuf) = out_time;
/* now we are ready to push the buffer. Save the seqnum and release the lock
* so the other end can push stuff in the queue again. */
@ -1147,7 +1125,9 @@ push_buffer:
JBUF_UNLOCK (priv);
/* push buffer */
GST_DEBUG_OBJECT (jitterbuffer, "Pushing buffer %d", seqnum);
GST_DEBUG_OBJECT (jitterbuffer,
"Pushing buffer %d, timestamp %" GST_TIME_FORMAT, seqnum,
GST_TIME_ARGS (out_time));
result = gst_pad_push (priv->srcpad, outbuf);
if (result != GST_FLOW_OK)
goto pause;
@ -1208,39 +1188,35 @@ gst_rtp_jitter_buffer_query (GstPad * pad, GstQuery * query)
* own */
GstClockTime min_latency, max_latency;
gboolean us_live;
GstPad *peer;
GstClockTime our_latency;
if ((peer = gst_pad_get_peer (priv->sinkpad))) {
if ((res = gst_pad_query (peer, query))) {
gst_query_parse_latency (query, &us_live, &min_latency, &max_latency);
if ((res = gst_pad_peer_query (priv->sinkpad, query))) {
gst_query_parse_latency (query, &us_live, &min_latency, &max_latency);
GST_DEBUG_OBJECT (jitterbuffer, "Peer latency: min %"
GST_TIME_FORMAT " max %" GST_TIME_FORMAT,
GST_TIME_ARGS (min_latency), GST_TIME_ARGS (max_latency));
GST_DEBUG_OBJECT (jitterbuffer, "Peer latency: min %"
GST_TIME_FORMAT " max %" GST_TIME_FORMAT,
GST_TIME_ARGS (min_latency), GST_TIME_ARGS (max_latency));
/* store this so that we can safely sync on the peer buffers. */
JBUF_LOCK (priv);
priv->peer_latency = min_latency;
our_latency = ((guint64) priv->latency_ms) * GST_MSECOND;
JBUF_UNLOCK (priv);
/* store this so that we can safely sync on the peer buffers. */
JBUF_LOCK (priv);
priv->peer_latency = min_latency;
our_latency = ((guint64) priv->latency_ms) * GST_MSECOND;
JBUF_UNLOCK (priv);
GST_DEBUG_OBJECT (jitterbuffer, "Our latency: %" GST_TIME_FORMAT,
GST_TIME_ARGS (our_latency));
GST_DEBUG_OBJECT (jitterbuffer, "Our latency: %" GST_TIME_FORMAT,
GST_TIME_ARGS (our_latency));
min_latency += our_latency;
/* max_latency can be -1, meaning there is no upper limit for the
* latency. */
if (max_latency != -1)
max_latency += our_latency * GST_MSECOND;
min_latency += our_latency;
/* max_latency can be -1, meaning there is no upper limit for the
* latency. */
if (max_latency != -1)
max_latency += our_latency;
GST_DEBUG_OBJECT (jitterbuffer, "Calculated total latency : min %"
GST_TIME_FORMAT " max %" GST_TIME_FORMAT,
GST_TIME_ARGS (min_latency), GST_TIME_ARGS (max_latency));
GST_DEBUG_OBJECT (jitterbuffer, "Calculated total latency : min %"
GST_TIME_FORMAT " max %" GST_TIME_FORMAT,
GST_TIME_ARGS (min_latency), GST_TIME_ARGS (max_latency));
gst_query_set_latency (query, TRUE, min_latency, max_latency);
}
gst_object_unref (peer);
gst_query_set_latency (query, TRUE, min_latency, max_latency);
}
break;
}

View file

@ -27,6 +27,9 @@
GST_DEBUG_CATEGORY_STATIC (rtp_jitter_buffer_debug);
#define GST_CAT_DEFAULT rtp_jitter_buffer_debug
#define MAX_WINDOW RTP_JITTER_BUFFER_MAX_WINDOW
#define MAX_TIME (2 * GST_SECOND)
/* signals and args */
enum
{
@ -61,18 +64,11 @@ rtp_jitter_buffer_class_init (RTPJitterBufferClass * klass)
static void
rtp_jitter_buffer_init (RTPJitterBuffer * jbuf)
{
gint i;
jbuf->packets = g_queue_new ();
jbuf->base_time = -1;
jbuf->base_rtptime = -1;
jbuf->ext_rtptime = -1;
for (i = 0; i < 100; i++) {
jbuf->window[i] = 0;
}
jbuf->window_pos = 0;
jbuf->window_size = 100;
jbuf->window_filling = TRUE;
jbuf->window_min = 0;
jbuf->skew = 0;
@ -183,9 +179,17 @@ rtp_jitter_buffer_get_clock_rate (RTPJitterBuffer * jbuf)
*
* Both the window and the weighting used for averaging influence the accuracy
* of the drift estimation. Finding the correct parameters turns out to be a
* compromise between accuracy and inertia.
* compromise between accuracy and inertia.
*
* We use a 2 second window or up to 512 data points, which is statistically big
* enough to catch spikes (FIXME, detect spikes).
* We also use a rather large weighting factor (125) to smoothly adapt. During
* startup, when filling the window) we use a parabolic weighting factor, the
* more the window is filled, the faster we move to the detected possible skew.
*
* Returns: @time adjusted with the clock skew.
*/
static void
static GstClockTime
calculate_skew (RTPJitterBuffer * jbuf, guint32 rtptime, GstClockTime time)
{
guint64 ext_rtptime;
@ -193,7 +197,12 @@ calculate_skew (RTPJitterBuffer * jbuf, guint32 rtptime, GstClockTime time)
gint64 delta;
gint64 old;
gint pos, i;
GstClockTime gstrtptime;
GstClockTime gstrtptime, out_time;
/* we don't have an arrival timestamp so we can't do skew detection. FIXME, we
* should still apply a timestamp based on RTP timestamp and base_time */
if (time == -1)
return -1;
ext_rtptime = gst_rtp_buffer_ext_timestamp (&jbuf->ext_rtptime, rtptime);
@ -218,25 +227,39 @@ calculate_skew (RTPJitterBuffer * jbuf, guint32 rtptime, GstClockTime time)
if (jbuf->window_filling) {
/* we are filling the window */
GST_DEBUG ("filling %d %" G_GINT64_FORMAT ", diff %" G_GUINT64_FORMAT, pos,
delta, send_diff);
GST_DEBUG ("filling %d %" G_GINT64_FORMAT ", send_diff %" G_GUINT64_FORMAT,
pos, delta, send_diff);
jbuf->window[pos++] = delta;
/* calc the min delta we observed */
if (pos == 1 || delta < jbuf->window_min)
jbuf->window_min = delta;
if (send_diff >= 2 * GST_SECOND || pos >= 100) {
if (send_diff >= MAX_TIME || pos >= MAX_WINDOW) {
jbuf->window_size = pos;
/* window filled, fill window with min */
/* window filled */
GST_DEBUG ("min %" G_GINT64_FORMAT, jbuf->window_min);
for (i = 0; i < jbuf->window_size; i++)
jbuf->window[i] = jbuf->window_min;
/* the skew is initially the min */
/* the skew is now the min */
jbuf->skew = jbuf->window_min;
jbuf->window_filling = FALSE;
} else {
gint perc_time, perc_window, perc;
/* figure out how much we filled the window, this depends on the amount of
* time we have or the max number of points we keep. */
perc_time = send_diff * 100 / MAX_TIME;
perc_window = pos * 100 / MAX_WINDOW;
perc = MAX (perc_time, perc_window);
/* make a parabolic function, the closer we get to the MAX, the more value
* we give to the scaling factor of the new value */
perc = perc * perc;
/* quickly go to the min value when we are filling up, slowly when we are
* just starting because we're not sure it's a good value yet. */
jbuf->skew =
(perc * jbuf->window_min + ((10000 - perc) * jbuf->skew)) / 10000;
jbuf->window_size = pos + 1;
}
} else {
@ -265,7 +288,7 @@ calculate_skew (RTPJitterBuffer * jbuf, guint32 rtptime, GstClockTime time)
jbuf->window_min = min;
}
/* average the min values */
jbuf->skew = (jbuf->window_min + (15 * jbuf->skew)) / 16;
jbuf->skew = (jbuf->window_min + (124 * jbuf->skew)) / 125;
GST_DEBUG ("new min: %" G_GINT64_FORMAT ", skew %" G_GINT64_FORMAT,
jbuf->window_min, jbuf->skew);
}
@ -273,6 +296,17 @@ calculate_skew (RTPJitterBuffer * jbuf, guint32 rtptime, GstClockTime time)
if (pos >= jbuf->window_size)
pos = 0;
jbuf->window_pos = pos;
/* the output time is defined as the base timestamp plus the RTP time
* adjusted for the clock skew .*/
out_time = jbuf->base_time + send_diff + jbuf->skew;
GST_DEBUG ("base %" GST_TIME_FORMAT ", diff %" GST_TIME_FORMAT ", skew %"
G_GINT64_FORMAT ", out %" GST_TIME_FORMAT,
GST_TIME_ARGS (jbuf->base_time), GST_TIME_ARGS (send_diff),
jbuf->skew, GST_TIME_ARGS (out_time));
return out_time;
}
static gint
@ -296,7 +330,7 @@ compare_seqnum (GstBuffer * a, GstBuffer * b, RTPJitterBuffer * jbuf)
* rtp_jitter_buffer_insert:
* @jbuf: an #RTPJitterBuffer
* @buf: a buffer
* @time: a timestamp when this buffer was received in nanoseconds
* @time: a running_time when this buffer was received in nanoseconds
*
* Inserts @buf into the packet queue of @jbuf. The sequence number of the
* packet will be used to sort the packets. This function takes ownerhip of
@ -327,11 +361,11 @@ rtp_jitter_buffer_insert (RTPJitterBuffer * jbuf, GstBuffer * buf,
return FALSE;
/* do skew calculation by measuring the difference between rtptime and the
* receive time */
if (time != -1) {
rtptime = gst_rtp_buffer_get_timestamp (buf);
calculate_skew (jbuf, rtptime, time);
}
* receive time, this function will retimestamp @buf with the skew corrected
* running time. */
rtptime = gst_rtp_buffer_get_timestamp (buf);
time = calculate_skew (jbuf, rtptime, time);
GST_BUFFER_TIMESTAMP (buf) = time;
if (list)
g_queue_insert_before (jbuf->packets, list, buf);
@ -350,7 +384,9 @@ rtp_jitter_buffer_insert (RTPJitterBuffer * jbuf, GstBuffer * buf,
* rtp_jitter_buffer_pop:
* @jbuf: an #RTPJitterBuffer
*
* Pops the oldest buffer from the packet queue of @jbuf.
* Pops the oldest buffer from the packet queue of @jbuf. The popped buffer will
* have its timestamp adjusted with the incomming running_time and the detected
* clock skew.
*
* Returns: a #GstBuffer or %NULL when there was no packet in the queue.
*/

View file

@ -43,6 +43,7 @@ typedef struct _RTPJitterBufferClass RTPJitterBufferClass;
*/
typedef void (*RTPTailChanged) (RTPJitterBuffer *jbuf, gpointer user_data);
#define RTP_JITTER_BUFFER_MAX_WINDOW 512
/**
* RTPJitterBuffer:
*
@ -59,7 +60,7 @@ struct _RTPJitterBuffer {
GstClockTime base_time;
GstClockTime base_rtptime;
guint64 ext_rtptime;
gint64 window[100];
gint64 window[RTP_JITTER_BUFFER_MAX_WINDOW];
guint window_pos;
guint window_size;
gboolean window_filling;