There is a report (#1342) of a device setting multiple bits for AAC
object type in SetConfiguration, although this appears to be forbidden.
It's not completely clear if this was due to e.g. some BlueZ bug, but it
should be safe to be lax and try to guess what is wanted in such case,
instead of being strict, in case it was due to device bug.
Make easier to package A2DP codecs separately, by splitting each to a
separate SPA plugin. Adjust the code to not use a global variable for
the codec list.
The A2DP SPA interface API is in the bluez5 private headers, and not
exposed in installed SPA headers, as it's too close to the
implementation.
Mark some structures, arrays static/const at various places.
In some cases this prevents unnecessary initialization
when a function is entered.
All in all, the text segments across all shared
libraries are reduced by about 2 KiB. However,
the total size increases by about 2 KiB as well.
Let codec decides when rtp packet need to be sent (terminated by MTU size in most case).
LDAC encoding loop can now be terminated by reading if frame_num is written, no 'frame_count' updating is needed.
RTP payload fragmentation can now be implemented more easily based on this.
Initial Props value are parsed from device settings, further changes are triggered by 'set_param' on a2dp node.
Codec can then use props to tweak its transcoder.
