I acquired Switch v1.29 to convert dvf files (SONY digital recorder format) to mp3 for general use.
The program is working well for that purpose.
But the conversion increases file size by a factor of 6.6. A 83 minute lecture in mp3 format takes 78MB.
How do I compress the mp3 files so that they can still be used by general users, and what sort of compression factor should I expect?