mpegtspacketizer: Handle PCR issues with adaptive streams

A lot of content producers out there targetting "adaptive streaming" are riddled
with non-compliant PCR streams (essentially all the players out there just use
PTS/DTS and don't care about the PCR).

In order to gracefully cope with these, we detect them appropriately and any
small (< 15s) PCR resets get gracefully ignored.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1785>
This commit is contained in:
Edward Hervey 2020-11-09 18:27:14 +01:00 committed by Edward Hervey
parent 168b5f6536
commit a2a73c02ef

View file

@ -1386,7 +1386,19 @@ calculate_skew (MpegTSPacketizer2 * packetizer,
/* Small jumps backward, assume some arrival jitter and skip it */
send_diff = 0;
if (pcr->last_pcrtime - gstpcrtime < GST_SECOND) {
/* The following code are the different ways we deal with small-ish
* jitter, ranging in severity from "can be ignored" to "this needs a full
* resync" */
if (time == pcr->base_time) {
/* If this comes from a non-fully-timestamped source (i.e. adaptive
* streams), then cope with the fact that some producers generate utter
* PCR garbage on fragment ends.
*
* We detect this comes from a non-fully-timestamped source by the fact
* that the buffer time never changes */
GST_DEBUG ("Ignoring PCR resets on non-fully timestamped stream");
} else if (pcr->last_pcrtime - gstpcrtime < GST_SECOND) {
GST_WARNING
("(small) backward timestamps at server or no buffer timestamps. Ignoring.");
/* This will trigger the no_skew logic before but leave other state
@ -1444,8 +1456,8 @@ calculate_skew (MpegTSPacketizer2 * packetizer,
* changed too quickly we have to resync because the server likely restarted
* its timestamps. */
if (ABS (delta - pcr->skew) > packetizer->pcr_discont_threshold) {
GST_WARNING ("delta - skew: %" GST_TIME_FORMAT " too big, reset skew",
GST_TIME_ARGS (delta - pcr->skew));
GST_WARNING ("delta - skew: %" GST_STIME_FORMAT " too big, reset skew",
GST_STIME_ARGS (delta - pcr->skew));
mpegts_packetizer_resync (pcr, time, gstpcrtime, TRUE);
send_diff = 0;
delta = 0;