In Audacity 1.2, there is one audio 'clip' per track. There is
no easy way to time-shift part of a track without moving the
rest. In Audacity 1.3, you can split a single track into multiple
clips. You can move these clips around between different tracks,
making it easy to construct complex compositions out of hundreds
of smaller audio samples.
3. Selection Bar
In Audacity 1.2, the current selection is contained in a
status bar at the bottom of the window. In Audacity 1.3,
this is replaced by a fully functional Selection Bar, which
displays and controls the current selection (your choice of
Start and End, or Start and Length), and the current audio
position. The selection bar is fully editable - just click
in any field and type to change the current selection precisely.
In addition, many formatting options allow you to view times in
different units, such as samples, CD frames, or NTSC video frames.
4. Improved Label Tracks
Label Tracks are Audacity's way for you to create markings 3
and annotations within your project. In Audacity 1.3, Label
Tracks are much improved, with support for overlapping labels,
and support for modifying both the left and right edge of the
label region just by clicking and dragging.
5. QuickTime and Audio Units on Mac OS X
On Mac OS X, Audacity can now import and audio file supported
by Apple's QuickTime technology. This includes .MOV and .MP4
(AAC) files. Unfortunately encrypted audio files (such as