- NDI HX Camera Android in the past used 1ns instead of 100ns as unit
for timecodes/timestamps.
- NDI HX Camera iOS uses 0 for all timecodes and the same non-zero
value for all audio timestamps
Detect such situations and try to compensate for them. Also add a new
"auto" timestamping mode that prefers to use timecodes and otherwise
falls back to timestamps or receive times.
Fixes https://github.com/teltek/gst-plugin-ndi/issues/79
Audio/video are in practice not always from the same clock and can have
different behaviours with regards to clock rate and jitter. Handling
them separately generally gives better results for the timestamps output
by the source element.