# US 12,002,478 B2 · Methods and apparatus to perform audio watermarking and watermark detection and extraction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,002,478 B2 - Document ID: US12002478B2 - Status: Granted - Kind: B2 - Application number: 17/860,920 - Filed: 2022-07-08 - Published: 2022-11-03 - Granted: 2024-06-04 - Earliest claimed: 2008-10-24 - Assignees: The Nielsen Company (US), LLC - Applicants: The Nielsen Company (US), LLC - Inventors: Venugopal Srinivasan; Alexander Pavlovich Topchy - Web page: https://patentgrep.com/patent/US12002478B2 ## CPC - G10L 19/018: Audio watermarking, i.e. embedding inaudible data in the audio signal - G10L 19/0208: {Subband vocoders} - G10L 19/173: {Transcoding, i.e. converting between two coded representations avoiding cascaded coding-decoding} - G11B 20/10: Digital recording or reproducing - H04H 20/31: using in-band signals, e.g. subsonic or cue signal - H04H 60/37: for identifying segments of broadcast information, e.g. scenes or extracting programme ID - H04H 60/58: of audio {(determination or detection of speech characteristics in general G10L25/00; speech recognition in general G10L15/00)} - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) - H04H: BROADCAST COMMUNICATION (multiplex communication H04J; pictorial communication aspects of broadcast systems H04N) ## Abstract Example methods and apparatus to audio watermarking and watermark detection and extraction are disclosed herein. An example apparatus disclosed herein includes memory, computer readable instructions, and processor circuitry to execute the computer readable instructions to at least detect a first symbol, a second symbol, a third symbol, and a fourth symbol sequentially in encoded audio samples, determine whether the first symbol is a synchronization symbol, in response to a determination that the first symbol is a synchronization symbol, determine that the first symbol and the third symbol are associated with a first message and the second symbol and the fourth symbol are associated with a second message, and output at least one of the first message or the second message. ## Claims ### Claim 1 An apparatus to transform media content into a message, the apparatus comprising: memory; computer readable instructions; and one or more processors configured to execute the computer readable instructions to at least: detect a first symbol, a second symbol, a third symbol, and a fourth symbol sequentially in encoded audio samples; determine whether the first symbol is a synchronization symbol; in response to a determination that the first symbol is a synchronization symbol, determine that the first symbol and the third symbol are associated with a first message and the second symbol and the fourth symbol are associated with a second message; and output at least one of the first message or the second message in response to a determination that a number of audio samples between the first message and the second message corresponds to an encoding repetition rate. ### Claim 2 (depends on 1) The apparatus as defined in claim 1, wherein the one or more processors are configured to store the first symbol, the second symbol, the third symbol, and the fourth symbol in at least one circular buffer. ### Claim 3 (depends on 1) The apparatus as defined in claim 1, wherein the one or more processors are configured to store the first symbol in a first location of a first circular buffer, the second symbol in a second location in a second circular buffer, the third symbol in a third location in the first circular buffer, and the fourth symbol in a fourth location in the second circular buffer, the first location of the first circular buffer corresponding to the second location in the second circular buffer and the third location in the first circular buffer corresponding to the fourth location in the second circular buffer, the first circular buffer and the second circular buffer corresponding to a first set of circular buffers. ### Claim 4 (depends on 3) The apparatus as defined in claim 3, wherein the one or more processors are configured to store the first symbol, the second symbol, the third symbol, and the fourth symbol as a data symbol in a second set of circular buffers different from the first set of circular buffers. ### Claim 5 (depends on 4) The apparatus as defined in claim 4, wherein the one or more processors are configured to: determine whether the first symbol is a pre-existing code synchronization symbol; and in response to a determination that the first symbol is the pre-existing code synchronization symbol, determine that the encoded audio samples include a first set of encoded messages and a second set of encoded messages that were encoded in the encoded audio samples prior to the first set of encoded messages being encoded. ### Claim 6 (depends on 5) The apparatus as defined claim 5, wherein the one or more processors are configured to, in response to the determination that the first symbol is the pre-existing code synchronization symbol, identify the second set of encoded messages based on the data symbol in the second set of circular buffers. ### Claim 7 (depends on 1) The apparatus as defined in claim 1, wherein the one or more processors are configured to: determine whether the first message matches the second message; and in response to a determination that the first message matches the second message, output a single message corresponding to the first message and the second message. ### Claim 8 A non-transitory computer readable medium comprising instructions to cause a machine to at least: detect a first symbol, a second symbol, a third symbol, and a fourth symbol sequentially in encoded audio samples; determine whether the first symbol is a synchronization symbol; in response to a determination that the first symbol is a synchronization symbol, determine that the first symbol and the third symbol are associated with a first message and the second symbol and the fourth symbol are associated with a second message; and output at least one of the first message or the second message in response to a determination that a number of audio samples between the first message and the second message corresponds to an encoding repetition rate. ### Claim 9 (depends on 8) The non-transitory computer readable medium as defined in claim 8, wherein the instructions, when executed, cause the machine to store the first symbol, the second symbol, the third symbol, and the fourth symbol in at least one circular buffer. ### Claim 10 (depends on 8) The non-transitory computer readable medium as defined in claim 8, wherein the instructions, when executed, further cause the machine to store the first symbol in a first location of a first circular buffer, the second symbol in a second location in a second circular buffer, the third symbol in a third location in the first circular buffer, and the fourth symbol in a fourth location in the second circular buffer, the first location of the first circular buffer corresponding to the second location in the second circular buffer and the third location in the first circular buffer corresponding to the fourth location in the second circular buffer, the first circular buffer and the second circular buffer corresponding to a first set of circular buffers. ### Claim 11 (depends on 10) The non-transitory computer readable medium as defined in claim 10, wherein the instructions, when executed, further cause the machine to store the first symbol, the second symbol, the third symbol, and the fourth symbol as a data symbol in a second set of circular buffers different from the first set of circular buffers. ### Claim 12 (depends on 11) The non-transitory computer readable medium as defined in claim 11, wherein the instructions, when executed, further cause the machine to store to: determine whether the first symbol is a pre-existing code synchronization symbol; and in response to a determination that the first symbol is the pre-existing code synchronization symbol, determine that the encoded audio samples include a first set of encoded messages and a second set of encoded messages that were encoded in the encoded audio samples prior to the first set of encoded messages being encoded. ### Claim 13 (depends on 12) The non-transitory computer readable medium as defined in claim 12, wherein the instructions, when executed, further cause the machine to, in response to the determination that the first symbol is the pre-existing code synchronization symbol, identify the second set of encoded messages based on the data symbol in the second set of circular buffers. ### Claim 14 (depends on 11) The non-transitory computer readable medium as defined in claim 11, wherein the instructions, when executed, further cause the machine to: determine whether the first message matches the second message; and in response to a determination that the first message matches the second message, output a single message corresponding to the first message and the second message. ### Claim 15 A method to transform media content into a message, the method comprising: detecting a first symbol, a second symbol, a third symbol, and a fourth symbol sequentially in encoded audio samples; determining whether the first symbol is a synchronization symbol; in response to a determination that the first symbol is a synchronization symbol, determining that the first symbol and the third symbol are associated with a first message and the second symbol and the fourth symbol are associated with a second message; and outputting at least one of the first message or the second message in response to a determination that a number of audio samples between the first message and the second message corresponds to an encoding repetition rate. ### Claim 16 (depends on 15) The method as defined in claim 15, further including storing the first symbol, the second symbol, the third symbol, and the fourth symbol in at least one circular buffer. ### Claim 17 (depends on 15) The method as defined in claim 15, further including storing the first symbol in a first location of a first circular buffer, the second symbol in a second location in a second circular buffer, the third symbol in a third location in the first circular buffer, and the fourth symbol in a fourth location in the second circular buffer, the first location of the first circular buffer corresponding to the second location in the second circular buffer and the third location in the first circular buffer corresponding to the fourth location in the second circular buffer, the first circular buffer and the second circular buffer corresponding to a first set of circular buffers. ### Claim 18 (depends on 17) The method as defined in claim 17, further including storing the first symbol, the second symbol, the third symbol, and the fourth symbol as a data symbol in a second set of circular buffers different from the first set of circular buffers. ### Claim 19 (depends on 18) The method as defined in claim 18, further including: determining whether the first symbol is a pre-existing code synchronization symbol; and in response to a determination that the first symbol is the pre-existing code synchronization symbol, determining that the encoded audio samples include a first set of encoded messages and a second set of encoded messages that were encoded in the encoded audio samples prior to the first set of encoded messages being encoded. ### Claim 20 (depends on 19) The method as defined in claim 19, further including, in response to the determination that the first symbol is the pre-existing code synchronization symbol, identifying the second set of encoded messages based on the data symbol in the second set of circular buffers.