Server side 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:
• receiving an audio signal encoding one or more utterances including a first utterance;
• determining whether at least a portion of the first utterance satisfies a first threshold of being at least a portion of a key phrase;
• in response to determining that at least the portion of the first utterance satisfies the first threshold of being at least a portion of a key phrase, sending the audio signal to a server system that determines whether the first utterance satisfies a second threshold of being the key phrase, the second threshold being more restrictive than the first threshold;
• and
• receiving, from the server system, data that indicates that the server system determined that the first utterance does not satisfy the second threshold.

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:

• receiving an audio signal encoding one or more utterances including a first utterance;
• determining whether at least a portion of the first utterance satisfies a first threshold of being at least a portion of a key phrase;
• in response to determining that at least the portion of the first utterance satisfies the first threshold of being at least a portion of a key phrase, sending the audio signal to a server system that determines whether the first utterance satisfies a second threshold of being the key phrase, the second threshold being more restrictive than the first threshold;
• and
• receiving, from the server system, data that indicates that the server system determined that the first utterance does not satisfy the second threshold.