c# - How to recognize a phrase from a voice file

Question

How to get the engine to successfully recognize a phrase from a voice file (wav/mp3/etc..)?

For example, if I'll have a voice file and a written text of the context of the same file, so to make it recognize the written words in the voice file.

I tried to play around with the SpeechRecognitionEngine, but without success so far.

I'll appreciate ideas, since this is my first time dealing with Speech Recognition techniques.

I've seen examples of speech-to-text using dictionaries, but I'm not sure how it can be useful here. I was thinking of maybe converting the all voice file to text, and then simply look for the specific phrase in that text, but I don't think it's the right way. Doesn't seem to make sense to convert for example 5hrs voice to text.... or maybe to use the specific phrase as a "dictionary" and to look for this item in the voice file.

Answer 1

It seems you need to look for a specific word in a long file. This technique is called "Keyword Spotting", it's quite different from speech recognition, way more efficient. Obviosly you do not need to transcribe the whole file to search a word in it, you can quickly scan through the file. Microsoft Speech Recognition engine have very limited support for keyword spotting.

Open source engines like CMUSphinx could be used to implement the keyword spotting efficiently. See for the further references the information on how to implement wake-up listening with pocketsphinx.

For the more information on the underlying algorithms see ACOUSTIC KEYWORD SPOTTING IN SPEECH WITH APPLICATIONs TO DATA MINING