Audio file transcription

Hi ..I am trying to find out a solution (cloud service or salesforce app) so that I can call from my salesforce instance to transcribe audio files (mp3) to text files. Like, for example, I get an audio recording from the telephone provider on calls and get it stored as attachments on records in Salesforce. I would like to pass that audio file to a service that would generate a text file that I would also attach to this record.

Any help?