Decoupling the audio from the video causes the audio to be played right
when it's received rather than attempt to sync up to the video frames.
This is useful with certain async sources/devices when the audio/video
timestamps are not reliable.
Naturally because it plays audio right when it's received, this should
only be used when the async source is operating in unbuffered mode,
otherwise the video frame timing will be out of sync by the amount of
buffering the video currently has.
(Note: This commits also modifies the linux-pulseaudio, mac-capture, and
win-wasapi plugins)
Do not prevent the targeted output device from being monitored if the
selected monitor output device is a different one.
Closesjp9000/obs-studio#872
On windows, when a source has only audio (no video) yet is marked as
capable of both video and audio, it would be programmed to expect a
video frame to synchronize with. This fixes that potential issue by
detecting whether any video is actually playing or not.
Adds functions to turn on audio monitoring to allow the user to hear
playback of an audio source over the user's speaker. It can be set to
turn off monitoring and only output to stream, or it can be set to
output only to monitoring, or it can be set to both.
On windows, audio monitoring uses WASAPI. Windows also is capable of
syncing the audio to the video according to when the video frame itself
was played.
On mac, it uses AudioQueue.
On linux, it's not currently implemented and won't do anything (to be
implemented).
jp9000
Richard Stanway
Shaolin