[ardour-dev] latest CVS commit

[Paul Davis]

This commit fixes several issues with monitoring and metering. First,
here is the state table derived from mantis #177, and it shows what is
monitored by a track depending on various states:

("AI" is auto-input)

                    AI off     AI on
        ------------------------------
        [stopped]:
        rec en:     input      input
        rec dis:    tape       input
	          (silent)   

        [rolling]:
        rec en:      input     tape
        rec dis:     tape      tape

        [recording]:
        rec en:      input     input
        rec dis:     tape      tape

This finally matches the table for the Alesis M20, from which
"autoinput" was derived.

Secondly, if monitoring is disabled, then no track should ever be
audible unless it is playing back existing material.

Finally, metering has now been subtly modified.

When rec-enabled, the "pre" button will now always cause
metering to reflect the inputs to the track, whether we are actively
recording or not.

When not rec-enabled, the "pre" button will cause metering
to reflect the signal level immediately pre-fader.

There may be still holes in this scheme, but now its your turn (once
again) to find them and report back.

       * libardour: 0.847.1

--p