Flash MX 2004.
soundItem.compressionType
Property; a string that specifies that compression type for a sound in the library. Acceptable values are "Default", "ADPCM", "MP3", "Raw", and "Speech". If you want to specify a value for this property, set soundItem.useImportedMP3Quality to false.
The following example changes an item in the library to compression type Raw:
fl.getDocumentDOM().library.items[0].compressionType = "Raw";The following example changes the compression type of the selected library items to Speech:
fl.getDocumentDOM().library.getSelectedItems().compressionType = "Speech";