I want to be able to capture live audio and loop it, with positional info for each stream. But there's no way to get real-time positional info from [mc.groove~]? And there is with [mc.sfplay~], but it can't play from [buffer]?
If I'm reading the documentation correctly, I think you can use the rightmost output from mc.groove~ to get what you need:
Out right outlet: Sync output. During the loop portion of the sample, this outlet outputs a signal that goes from 0. when the loop starts to 1. when the loop ends.
Note: In order for buffer playback to begin (and consequently for sync output), one of the groove~ object's output channels must be connected to another signal object.