Efficient utterance-specific endpointer triggering for always-on hotwording

A system comprising:

• one or more computers;
• and
• one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising:
• obtaining an audio input signal representing an utterance of a user;
• determining that a shape of at least a portion of the audio input signal matches a shape of at least a portion of an audio trigger signal corresponding to a keyword;
• and
• based at least on determining that the shape of at least the portion of the audio input signal matches the shape of at least the portion of an audio trigger signal corresponding to the keyword, classifying the utterance as a trigger utterance that corresponds to the keyword.

A non-transitory computer-readable medium storing software comprising instructions executable by one or more computers which, upon such execution, cause the one or more computers to perform operations comprising:

• obtaining an audio input signal representing an utterance of a user;
• determining that a shape of at least a portion of the audio input signal matches a shape of at least a portion of an audio trigger signal corresponding to a keyword;
• and
• based at least on determining that the shape of at least the portion of the audio input signal matches the shape of at least the portion of an audio trigger signal corresponding to the keyword, classifying the utterance as a trigger utterance that corresponds to the keyword.