website offering audio transcription speech to text

website offering transcription speech to text a website that allows anonymous visitors to transcript English speech files to written text. Two different chances: small audio files and large audio files. small audio files: visitors upload audio file and website convert them i written text. large audio files: This transcription service have to be done locally: people can't upload their mp3 files on server. The transcription service works from the client side, no bandiwth consumption except for script downloading, but visitor does need to open the website to have the task done