Enables clocks to wait if the main sync clock has not been started yet. An example of this is a video stream (video/audio) being synced to the video clock. If an audio frame gets produced before the video clock has started it will wait.
Add referencing counting to determine when to release a clock Due to no fixed ownership of clocks (packets, frames, decoders and refresh thread all may own a clock at some point).
The bug was undetected because it accidentally fell into an error case that slept the correct amount of time. pthread_cond_timedwait takes an absolute time in the future to wait until. The value we were passing was always in the past so it was immediately failing with a TIMEDOUT error code.
This lets the decoder make decisions based on whether it is a hardware decoder or not. Specifically, hardware decoders are more strict as to which frames can be dropped in an h264 stream.
FFMpeg has an issue where png decoding will not correctly
begin until its optimal-thread-detection finishes in
multi-threaded mode. This unfortunately is after decoding
has begun.
