Editing : Editing Clips and Selections : Compacting an Audio File

Compacting an Audio File
The Compact command deletes unused portions of audio files to conserve disk space, and to prepare for cleaner hard drive back-ups. The Compact Selected command also deletes any audio files for which there are no clips on tracks referencing those files.
Because it permanently deletes audio data, the Compact command should be used only after you have completely finished your editing and are sure that you have no further use for the unused audio data.
The Compact command can pad the clips of the compacted file by a selectable amount. If clips in your session use crossfades, or if you want to pad the clips for the sake of any future trimming, you should enter an appropriate amount of padding (in milliseconds).
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The Compact command is destructive and cannot be undone. It permanently alters the original audio files. There is no way to recover data deleted by this command.
To compact an audio file:
1 In the Clip List, select the clip or clips you want to compact.
2 From the Clip List menu, choose Compact.
3 Enter the amount of padding in milliseconds that you want for each clip in the file.
4 Click Compact to compact the file or Cancel to cancel the command.
Once the Compact command has been completed, the session is saved automatically.