The previous commit (672378d20) was supposed to fix issues with the
encoder releasing while data was still being processed, but did not
account for when the encoder has never started up. That was my fault.
Furthermore, the way in which it was waiting to drain events was
incorrect. The encoder may still be active even though there aren't any
events queued. The proper way to wait for an async encoder to finish up
is to process output samples until it requests more input samples.
After I made it so that the encoder internal data gets destroyed when
all outputs stop using it (fa7286f8), the media foundation h264 encoder
started having crashes on shutdown. After a lot of testing, I realized
that the reason it started happening is almost assuredly because active
encoding events had not yet been completed.
After making it wait on those events by calling DrainEvents(true), the
crashes stopped. So asynchronous actions were clearly still occurring
and it was shutting down while data was still being processed, thus
leading to a crash.
Implements hardware encoders through the Media Foundation interface
provided by Microsoft.
Supports:
- Quicksync (Intel)
- VCE (AMD)
- NVENC (NVIDIA, might only be supported through MF on Windows 10)
Notes:
- NVENC and VCE do not appear to have proper CBR implementations. This
isn't a fault of our code, but the Media Foundation libraries.
Quicksync however appears to be fine.
