Burned subs to CDs

[Shannon]

Masked subs don't use frequency differencing, they use volume differencing. Since mp3 encoding works by removing what is commonly considered "useless data" - such as audio too low in volume to hear or too high in pitch to hear - you can't encode them either. (EDIT: To clarify, we use special methods to retain subliminal audio data in our .mp3s. You the customer won't be able to in the vast majority of cases.) It is impossible to verify these, and the only way to know if they're being damaged is to examine the ultrasonics. If the ultrasonics are damaged or significantly altered, then it's a good bet the masked program is also being stripped of its subliminal audio.