Proposal Easy Avoid Clipping on many tracks

The Problem
Multiple tracks will probably be collapsed. Therefore the gain sliders may be especially hard to access with a mouse. Probably the track info should be the first content to disappear when dragging the track up, not the last.

Tracking
Bug 565: Easier way to avoid clipping on multiple tracks. Update the Bugzilla issue with the consensus solution achieved here.

Proposed Solution
There are several ideas, not necessarily mutually exclusive, but of increasing complexity and functionality:
 * Shortcut and/or "always visible" master fader slider that moves all gain sliders by the same amount.
 * Incorporate the master fader slider into the playback meter (and the recording input slider into the recording meter).
 * Interface to select multiple tracks on which selected tracks the mute/gain/pan solo controls operate in tandem. Could be integrated into Mixer Board.
 * Automatic gain adjustment (Mix and Scale) so that the mix in unmuted tracks can never clip. Could be a control that sets the target level of the mix.
 * Separate mixing window (like Mixer Board but with a "Master-Fader" control).
 * Master-Fader or Master Envelope track, used additional to and independently of Envelope Tool.
 * Fader Automation. Adjust the Mixer Board or Track Control Panel gain sliders while playing then record the slider moves so you can render them if desired.

QA Backing
Gale: who prefers "automatic mix and scale", or a slider/shortcut to move all gain sliders in tandem. I understand these are easier to implement than envelope solutions (at least to begin with).

Automatic Mix and Scale
This means that the tracks never clip. If you add a track, or change a gain on one track, then on mix or playback the gain sliders adjust to respect the proportional volume of each track, without clipping. Probably best as a Preference to choose scaling or not.

Keyboard shortcut to move gain sliders in tandem
When the shortcut is held down, moving the gain slider on one track moves the gain sliders on all the other tracks by the same amount. User decides if the final level clips or not.

Master Fader Slider
See http://forum.audacityteam.org/viewtopic.php?p=185748#p185748 for idea by Steve/Bill for a Master Fader slider which would be accessible in two places
 * in a Master Fader Track (with envelope points written when moving the fader)
 * in Mixer Board.

Mixer Lister
Suggested by Alex Taddei. See http://wiki.audacityteam.org/pdf/mixer_lister.pdf. This idea creates a tabular interface for all the tracks, not unlike Mixer Board, with gain/pan/mute/solo controls and a right-click context menu for Sample Format and Sample Rate.

Gale 17Feb13: I give it a cautious welcome if integrated into Mixer Board as a way of changing controls on multiple selected tracks at the same time. I don't think we need "OK". If you lock tracks together by the checkbox, then the controls for those tracks move in sympathy and affect the Track Control Panels simultaneously. I am not sure how often you would want to change the sample rate or format of all (or individual) tracks - this may be unwanted. I'm not sure how often you would want to gain or pan large numbers of chosen multiple tracks by the same amount (as opposed to gaining or panning all tracks by the same amount). For gaining all tracks I still prefer a clean "Mix and Scale" Preference or a shortcut slider to move gain sliders in tandem.
 * Each track has a checkbox to select that track, and a "Select All" button.
 * Changing any control, rate or format in a selected track makes the same changes in all the selected tracks in the interface.
 * Tracks can be dragged up and down as in Track Control Panel (Mixer Board does not support this).
 * Changes are not applied to the Track Control Panels until pressing "OK" in the interface.
 * Selecting tracks in the interface does not select tracks for editing in Track Control Panel.

Indicative Feature Requests July 2012

 * One-step way to avoid clipping on multiple tracks:
 * Master Fader ability:
 * Automatic gain adjustment (Mix and Scale): so that the mix in unmuted tracks can never clip. Could be a control that sets the target level of the mix.
 * Shortcut that moves all gain sliders by same amount
 * Separate mixing window (like Mixer Board but with a "Master-Fader" control):
 * Master-Fader or Master Envelope track: Like the Envelope Tool but in its own track and applies to all tracks, used additional to and independently of Envelope Tool. On playback, fader position is interpolated (linearly in dB) between the track points and the result is added (in dB thus multiplied) with the current "envelope" value.


 * Fader Automation:
 * Adjust the Mixer Board or Track Control Panel gain sliders while playing then record the slider moves so you can render them if desired. . Common feature on many other multi-track audio programs. In this way one can build up a mix, adjusting individual tracks and tweaking levels until just right. This would first require changing to linear envelope points. Could be extended to panning (if we had a pan envelope).
 * Panning Envelope has 42 votes on Wiki Feature Requests.