Is it legal for my employer to record both audio/video of me during my shift without my consent?

As a general rule, videotaping employees in the workplace is legally permissable as long as it is limited to job performance and work activities. Accordingly, an employer may videotape to prevent such behavior such as employee theft and the like. However, such taperecordings may violate employees' rights to privacy if they are videotaped in areas considered private and personal, such as bathrooms, locker rooms and break rooms. Further, employers must notify all employees in writing that video surveillance is being conducted and where it is being used, as well as state the areas that are off limits from such surveillance.
As for voice recording employees, since there is no “expectation of privacy” in public areas (the lobby, stairwell, conference rooms, etc.), recording conversations in such areas is legal. Otherwise, recording employees without their permission is illegal unless the person recording the conversation is also a party to the conversation, although in some states all parties must consent to the recording (S.D. follows the 1-party consent rule).
 
To be certain of all of your rights under specific state law, you can contact your state's department of labor and/or consult directly with an employment law attorney in your area, they can best advise you further.