videorec: Appropriately rescale timestamps and duration
Applies to both audio and video for them to be in sync.
videorec: Always initialize audio and video time bases
In both context and stream.
videorec: Fix flushing encoders
When passing NULL frames, encoders empty their queues, but we have
to stop polling from them when they don't any more data.
[
bug #1] - Fixed simultaneous pressing of two arrow buttons on mobile