>>will this function only register changes to buffers ie.. from 128 to 512ms for mixing
No because mix recall only recalls project specific state not global preferences state.
>>change reverb fx to convolution reverb?
Yes. Mix recall will restore all effects used in user fx bins as well as the prochannel.
ie low latency plugins for recording swapped with pre determined fx for mixing/mastering.
Mix recall is very powerful and can be used for a lot of operations besides simply restoring a mix. For example you can do stuff like selectively change fx or settings in groups of tracks, reset offset mode settings or even reset an entire project to flat settings removing all plugins, envelopes mix settings. Its highly configurable.
The state that is saved via Mix recall is as follows:
Track controls. Track controls include the following parameters:
* Gain
* Pan
* Manual mute
* Automated mute
* Solo
* Volume trim
* Input gain
* Input pan
* Send gain
* Send pan
* Send enable
* Send pre/post
Track automation. All automation envelopes that live in tracks, including track parameters and plug-in parameters.
Track FX. All plug-ins that live in tracks, including ProChannel and synths that are referenced by tracks.
Bus controls. Bus controls include the same settings as tracks, but for buses.
Bus automation. All automation envelopes that live in buses, including bus parameters and plug-in parameters.
Bus FX. All plug-ins that live in buses, including ProChannel.
Mains. Main bus settings include the following parameters:
* Main bus left gain
* Main bus right gain
* Main bus left mute
* Main bus right mute
* Offset values. Apply any Offset Mode values. For details, see Envelope mode and Offset mode.
The preferences allow you to:
* Auto-save when switching scenes. Before loading a different Mix Scene, automatically save the current mix to the current Mix Scene.
* Apply to. Apply the operation to the entire project, or only to selected tracks or buses.
* Track/bus selection. Apply the operation only to selected tracks or buses.