There should be a managed latency control for VS API

[ph3-der-loewe]

There should be a sub-module of VS API to manage latency. This module should check the latency and adjust buffers and such according to the control goal.

There should be 3 different modes:

1. full automatic mode (may search a good latency which is not minimum to make it more robust against buffer underruns. Maybe it should soft control the latency to be at (min + (max - min)/2).)
2. get latency as low as possible. maybe with different levels of aggression.
3. fixed latency mode. A mode in which the closed loop control will try to get latency to a fixed and given value.

[ph3-der-loewe]

• Does mainly apply to buffered mode
• P-controller seems to be best for within/near tolerance band. Maybe different P-gain or additional D for out of band controlling to optimize speed. (Only of interest at start of stream and on change of target latency)
• Depends on changes in VIO layer to support better buffer control
• Can be done within normal calls to roar_vs_latency() and operate in background.

[ph3-der-loewe]

simple implementation is done.