Audio Window represents an audio waveform (Wave, MP3, Audio CD,...). Audio Window opens when you load a sound record from disk or when you record something with Wave Recorder. Only one Audio Window may be opened at a time.
Play All button plays back all the composition.
Play button plays the selection.
Pause button pauses the playback.
Stop button stops the playback
Transcribe button starts recognition of the selected fragment.
Select from Start button places the selection start at the beginning of the piece.
Select up to End button places the selection end at the end of the piece.
Left channel button selects the left stereo-recording channel for recognition.
Right channel button selects the right stereo-recording channel for recognition.
Combined channels button selects all of both the left and right stereo-recording channels for recognition. This option was used in previous WIDI versions.
Channel difference button selects the difference between left and right stereo-recording channels for recognition; this can be useful for removing the primary voice with a view to preparing recordings for karaoke.
Selection controls 
and 
show and set start and end of the selection.
Length control also acts as a "Select All" tool.
Selecting part of the wave - press the primary mouse button down above the Wave pane and move the mouse, then release the button.
Note: WIDI saves all audio files in the uncompressed Wave format. Be careful not to overwrite the original if you need it.