rtpjitterbuffer: add DTX functionality

Some audio-codecs (like opus) uses DTX (Discontinuous transmission),
in the way that they simply stop sending audio-packets when there is
no audio detected.

The expectation is then that the codec will use its internal PLC (packet
loss concealment) to create packets in place of those missing.

This patch is reusing the timer already existing for RTX and lost-events,
scheduling a lost-timer for the next sequence-number based on the
inter-packet spacing.
26 jobs for !600 with hgr/jb-dtx in 27 minutes and 32 seconds (queued for 2 seconds)
latest detached
Status Job ID Name Coverage
  Preparation
passed #2968323
gst indent

00:00:29

passed #2968321
manual
manifest

00:00:58

 
  Build
passed #2968341
gstreamer
build cerbero cross-android universal

00:09:50

passed #2968348
gst-ios-13.2
build cerbero cross-ios universal

00:22:19

passed #2968343
gstreamer
build cerbero cross win32

00:04:32

passed #2968345
gstreamer
build cerbero cross win64

00:05:55

passed #2968339
gstreamer
build cerbero fedora x86_64

00:04:38

passed #2968347
gst-macos-10.15
build cerbero macos x86_64

00:09:54

passed #2968330
build clang fedora x86_64

00:04:50

manual #2968336
1809 windows docker allowed to fail manual
build msys2
passed #2968325
build nodebug fedora x86_64

00:03:49

passed #2968326
build static fedora x86_64

00:03:43

passed #2968328
build static nodebug fedora x86_64

00:03:31

passed #2968332
1809 windows docker
build vs2017 amd64

00:12:34

passed #2968334
1809 windows docker
build vs2017 x86

00:12:56

 
  Test
passed #2968351
gstreamer
check fedora

00:05:39

passed #2968353
gstreamer
integration testsuites fedora 1/4

00:13:22

passed #2968354
gstreamer
integration testsuites fedora 2/4

00:15:59

passed #2968355
gstreamer
integration testsuites fedora 3/4

00:13:17

passed #2968356
gstreamer
integration testsuites fedora 4/4

00:14:16

passed #2968358
gstreamer
valgrind bad

00:06:29

passed #2968359
gstreamer
valgrind ges

00:06:41

passed #2968357
gstreamer
valgrind good

00:10:18

 
  Integrate
passed #2968360
cross-android universal examples

00:06:25

passed #2968362
gst-ios-13.2
cross-ios universal examples

00:03:42

passed #2968361
documentation

00:05:56