Audio Translation is the translation of audio content into written form in a different language. For example, you may have a focus group interview conducted in Mandarin, recorded and saved as an audio file like mp3 or video file like mp4, and you need it to be translated into an English transcript.
Subtitling Translation is sometimes categorised under this broad category. The difference between subtitling and audio translation is that subtitling involves the use of subtitling software and includes timecoding. A translator/subtitler makes judgement calls on words and expressions, sentence length and word order in order for subtitles to match the speakers in a natural manner that makes viewing easy and coherent.