* Do server PLI when sync is required.
A few changes
- Run key frame requester goroutine always. Runs every 200 ms which is
not bad.
- Post a key frame request when server knows it needs one, like after an
allocation. This ensures that the initial request is not delayed.
- Periodic check will ensure PLI for cases like all frame chains of a
dependency descriptor being broken.
* simplify
When starting from scratch (like mute -> unmute), it is possible
that the check sync does not detect a broken chain. That results
in PLIs not being sent and the video frozen till a gratuitous key
frame arrives.
Unclear why there are not PLIs from client side. That is something else to
dig into.
SVC has only one stream and when calculating reference time stamp,
irrespective of reference layer, reference time stamp will be the
same as the given time stamp as there is only one stream and no offset.
TODO: Need better all around SVC handling.
* Remove parked layer feature.
Not worth the added complexity.
Several reasons
- Not seeing black frames on pub mute always.
- If they are there, it can consume more than 30kbps if the parked layer
is high res. That is wasted bandwidth downstream when pub is muted.
- On resume, client some time sends PLI and that triggers a key frame
request.
But, leaving the separate `PubMuted` flag in forwarder in case we can
use it for better handling.
* need the request spatial
* Check for request layer lock only in the goroutine
* check before sending PLI
* max layer notifier worker
* test cleanup
* clean up
* do notification in the callback
* Mark active when switching to parked layer.
Parked layer lock is not a switch. It is just a restart at the same
layer.
* make explicit bool for switching
* Add ability to roll back video layer selection.
Not currently useful, but it is possible to do things like not
applying a layer switch if the switch point time stamp is too far back.
Add ability to roll back a layer switch and invoke rollback if
a packet was selected for forwarding, but a subsequent error or decision
to drop the packet can rollback layer switch if that was the switching
packet.
In current code, the paths where a packet can be dropped after selection
does not happen at switch points. So, it was okay to apply the selection
unconditionally. But, adding the call to rollback in the current code
also in all paths where packet is dropped after selection for consistent
code flow.
* separate switch for temporal layer
* Don't update dependency info if unordered packet received
* Trace all active svc chains for downtrack
* Try to keep lower decode target decodable
* remove comments
* Test case
* clean code
* solve comments
* Return max spatial layer from selectors.
With differing requirements of SVC and allowing overshoot in Simulcast,
selectors are best placed to indicate what is the max spatial layer when
they indicate a switch to max spatial layer.
* fix test
* prevent race
* Decode chains
* clean up
* clean up
* decode targets only on publisher side
* comment out supported codecs
* fix test compile
* fix another test compile
* Adding TODO notes
* chainID -> chainIdx
* do not need to check for switch up point when using chains, as long as chain integrity is good, can switch
* more comments
* address comments
cnderrauber