New patents are issued on Tuesdays by the USPTO. Both of today's Spotlight Patents concern aspects of digital fingerprinting. Assigned to Facebook, the first patent addresses techniques for managing silence in audio signal identification. Assigned to Google, the second patent addresses techniques for adding pitch shift resistance to an audio fingerprint.
9,679,583, "Managing silence in audio signal identification," assigned to Facebook
An audio identification system determines whether a portion of a sample of an audio signal includes silence and generates a test audio fingerprint for the audio signal based on the presence of silence. In one embodiment, the audio identification system uses a value indicating silence for a portion of the test audio fingerprint corresponding to the portion of the audio signal that includes silence. When comparing the test audio fingerprint to reference audio fingerprints, the portion of the test audio fingerprint including the value indicating the presence of silence is not used. In another embodiment, the audio identification system replaces the portion including silence with additive audio and generates a test audio fingerprint for comparison based on the resulting modified sample.
9,679,573, "System and method for adding pitch shift resistance to an audio fingerprint," assigned to Google.
Systems and techniques for adding pitch shift resistance to an audio fingerprint are presented. In particular, an audio track for a media file is received. A first audio fingerprint for the audio track with a first pitch shift and an Nth audio fingerprint for the audio track with an Mth pitch shift are generated, where N is an integer greater than or equal to two and M is an integer greater than or equal to two. A combined audio fingerprint is generated from at least the first audio fingerprint and the Nth audio fingerprint.