These shortcuts work in the subtitle editor. While a dialog is open it owns the keyboard, and while you type in a field the letter and arrow keys belong to the field.
Playback and navigation
Space
Play or pause (when audio is loaded)
J or ←
Skip back 5 seconds
L or →
Skip forward 5 seconds
↑ / ↓
Move to the previous or next line (Shift extends the selection)
Enter
Start typing in the current line
Esc
Clear the selection
Ctrl/⌘+A
Select all lines
Timing
[
Set the selected line’s start to the playhead
]
Set the selected line’s end to the playhead
Alt+← / Alt+→
Nudge selected lines earlier or later by 0.1 seconds (Shift: 1 second)
↑ / ↓ in a time field
Change that time by 0.1 seconds (Shift: 1 second)
Editing
Delete / Backspace
Delete the selected lines
Ctrl/⌘+B, I, U
Bold, italic, underline (selected words while typing, otherwise the selected lines)
Ctrl/⌘+S
Save (works even with the cursor in a text field)
Ctrl/⌘+Z
Undo
Ctrl/⌘+Shift+Z or Ctrl+Y
Redo
Ctrl+wheel
Zoom the waveform
FAQ
Can I run Clean Up with a shortcut?
No. The editor no longer has Clean Up; it is in Tools → Clean Up.