webrtcsink: implement mechanism to forward metas over control channel

It may be desirable for the frontend to receive ancillary information over the control channel.

Such information includes but is not limited to time code metas, support for other metas (eg custom meta) might be implemented in the future, as well as downstream events.

This patch implements a new info message, probes buffers that arrive at nicesink to look up timecode metas and potentially forwards them to the consumer when the forward-metas property is set appropriately.

Internally, a "dye" meta is used to trace the media identifier the packet we are about to send over relates to, as rtpfunnel bundles all packets together.

The example frontend code also gets a minor update and now logs info messages to the console.

cc @neodesys, @thiblahute :)

Don't forget to add the new "info" event to the js API documentation. Apart from this for me that's OK

added 1 commit

• 398485fe - webrtcsink: implement mechanism to forward metas over control channel

Compare with previous version

assigned to @gstreamer-merge-bot

mentioned in commit meh/gst-plugins-rs@9c0d3d49

added 41 commits

• 398485fe...1675e517 - 40 commits from branch gstreamer:main
• 9c0d3d49 - webrtcsink: implement mechanism to forward metas over control channel

Compare with previous version

assigned to @meh and unassigned @gstreamer-merge-bot

I couldn't merge this branch: CI failed! See pipeline https://gitlab.freedesktop.org/meh/gst-plugins-rs/-/pipelines/1273316.

added 1 commit

• 30b97dd2 - webrtcsink: implement mechanism to forward metas over control channel

Compare with previous version

assigned to @gstreamer-merge-bot and unassigned @meh

mentioned in commit meh/gst-plugins-rs@046f77e8

added 41 commits

• 30b97dd2...1675e517 - 40 commits from branch gstreamer:main
• 046f77e8 - webrtcsink: implement mechanism to forward metas over control channel

Compare with previous version

I couldn't merge this branch: CI failed! See pipeline https://gitlab.freedesktop.org/meh/gst-plugins-rs/-/pipelines/1273450.

assigned to @meh and unassigned @gstreamer-merge-bot

added 1 commit

• e356aa1c - webrtcsink: implement mechanism to forward metas over control channel

Compare with previous version

assigned to @gstreamer-merge-bot and unassigned @meh

mentioned in commit meh/gst-plugins-rs@6a23ae16

added 43 commits

• e356aa1c...db026ad5 - 42 commits from branch gstreamer:main
• 6a23ae16 - webrtcsink: implement mechanism to forward metas over control channel

Compare with previous version

merged

changed milestone to %0.14.0