New pending patent applications are published by the USPTO on Thursdays. This week's Spotlight Applications concern aspects of digital fingerprinting and digital watermarking. Assigned to Facebook, the first of this weeks Spotlight Applications discloses techniques for indexing based on time-variant transforms of an audio signal's spectrogram. Assigned to Nagravision, the second application discloses techniques for embedding watermark in uncompressed video data for use in a conditional access system.
20180047416, "Indexing based on time-variant transforms of an audio signal's spectrogram," assigned to Facebook.
An audio identification system generates audio fingerprints and indexes associated with the audio fingerprints based on discrete and overlapping frames within a sample of an audio signal. The system applies a time-to-frequency domain transform to a time-sequence of frames, which may be filtered. The audio identification system then applies a time-variant transformation (e.g., a Discrete Cosine Transform) to the transformed frames and generates an audio fingerprint and index by selecting sets of coefficients of the time-variant transformation. The system selects coefficients that are less sensitive to possible noise and/or distortions in the underlying signal, such as low-frequency coefficients. The time-variant transformation provides sufficient sampling among the indexes by incorporating the phase information of the frames into the indexes. The system stores the audio fingerprint and other identifying information by index for efficient retrieval and matching of the retrieved fingerprints.
20180048946, "Method and device to embed watermark in uncompressed video data," assigned to Nagravision (CH).
A system and method to watermark an uncompressed content received at a client device in a compressed form and encrypted by at least one content key, said content key as well as watermark instruction forming a Conditional Access Module (CAS) data, said CAS data being encrypted by a transmission key and comprising at least one signature to authenticate the CAS data, said client device comprising a CAS configured to process the CAS data, a descrambler having an input to receive the encrypted compressed content and an output to produce an compressed content, a decoder to convert the compressed content into uncompressed content, a watermark inserter connected to the output of the decoder, a secure activation module connected with the watermark inserter, a secure element connected with the watermark inserter and the secure activation module.