Sorry for bad search, but I only found this as related to variable tempo change editing:
There was proposal about marks, which could be dragged to control tempo change. I’m not sure, however, what is exactly supposed, so there is my version. There may be per-clip tempo editing mode. For begining is same as above proposal - there are control “points”, which could look more similar to selection borders.
Tempo edit mode.
When at least one tempo border is on some clip, it is meaned to be in tempo editing mode.
Since separate clips may be moved, tempo edit mode is probably makes sence only to be clip-wide.
When such mode is active, both original and changed audio data are stored.
Changed data are necessary to listen changes in progress.
Their update mode could be: auto or manual, auto - with optional timeout after user activity.
- blocked if data need update
- automatically update when pressed (makes sence in manual mode)
Exiting editing mode causes original data to be removed.
Other effects could work while in tempo editing, but should be applied to original data, to be preserved.
Tempo borders & regions.
Each mentioned point (further - margin) is only connection between regions, whose tempo are to be changed. When tempo editing is activated, there is one region for entire clip. Other margins are to be inserted (spliting regions).
Editing is to be done by dragging tempo margins horizontally (multiple margins could be selected for drag).
- when region is stretched - waveform, spectrogram, whatever represents data - may be just scaled.
- Per-region tempo change and other options could be displayed in overlay.
Tempo change per range could be locked/unlocked. When locked, dragging its margin moves entire range.
Example editing workflow:
- enter clip tempo editing
- create start/end ranges with locked tempo (alternative - use clip with pre/post sections cut, so that main clip has only modified range)
- stretch clip’s global tempo region
- subdivide region (insert more margins) and repeat 3 for each subrange unless satisfied
- finish editing (should exit tempo editing, fixing all changes).