# US 10,121,478 B2 · Audio watermark and synchronization tones for recording devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,121,478 B2 - Document ID: US10121478B2 - Status: Granted - Kind: B2 - Application number: 15/446,224 - Filed: 2017-03-01 - Published: 2017-09-14 - Granted: 2018-11-06 - Earliest claimed: 2016-03-10 - Assignees: TASER International, Inc. - Applicants: TASER International, Inc. - Inventors: James N. Reitz; Patrick W. Smith - Web page: https://patentgrep.com/patent/US10121478B2 ## CPC - G10L 19/018: Audio watermarking, i.e. embedding inaudible data in the audio signal - G11B 27/10: Indexing; Addressing; Timing or synchronising; Measuring tape travel - G11B 27/3009: {used signal is a pilot signal inside the frequency band of the recorded main information signal} - G11B 27/3045: {superimposed on the recorded main signal, e.g. burn-in-time code} - 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) ## Abstract A recording device, such as a video camera, emits audio watermarks (e.g., audible tones, inaudible tones) and records audio watermarks emitted by other recording devices. The audio watermarks provide information (e.g., data) such as an identifier of the camera and the identity of the operate. Audio watermarks may further include time information such as a timestamp indicating the time that the audio watermark was emitted by the camera. Audio watermarks may be emitted and recorded at intervals while recording an incident. A processing system, such as a digital video and audio processing system, may receive video information and recorded watermarks from multiple recording devices. The processing system may use the audio watermarks recorded by each recording device to determine which recording devices were in the vicinity of an incident. The processing system may also use the audio watermarks to align (e.g., synchronize) the video recorded by the various recording devices. Alignment of recorded video may permit synchronized playback of the recorded video from the various recording devices. Alignment may further identify at what point during an incident a recording device began and terminated recording. ## Claims ### Claim 1 A first camera comprising: a video sensor that collects video data at an incident; an audio sensor that collects audio data at the incident; a rendering engine; a first speaker; a control engine, the control engine includes a processor; and a data store; wherein: the data store stores a first identifier that identifies the first camera; the rendering engine receives the first identifier from the data store and renders a first audio watermark, the first audio watermark includes one or more tones that represent the first identifier; the first speaker outputs the first audio watermark; the audio data collected by the audio sensor includes the first audio watermark as output by the first speaker; the audio data collected by the audio sensor includes a second audio watermark, the second audio watermark output by a provided second speaker of a provided second camera at the incident, the second audio watermark includes one or more tones that represent a second identifier of the second camera; and the control engine stores the video data and the audio data, including the first audio watermark and the second audio watermark, in the data store. ### Claim 2 (depends on 1) The first camera of claim 1 wherein at least one of the first audio watermark and the second audio watermark is audible to a human. ### Claim 3 (depends on 1) The first camera of claim 1 wherein at least one of the first audio watermark and the second audio watermark is inaudible to a human. ### Claim 4 (depends on 1) The first camera of claim 1 wherein at least one of the first identifier and the second identifier include a numerical number. ### Claim 5 (depends on 1) The first camera of claim 1 wherein the first camera transfers the video data and the audio data to a server. ### Claim 6 (depends on 1) The first camera of claim 1 wherein: the control engine generates a timestamp; the rendering engine renders a first audio timestamp in accordance with the timestamp, the first audio timestamp includes one or more tones that represent the first audio timestamp; and the first speaker further outputs the first audio timestamp. ### Claim 7 (depends on 1) The first camera of claim 1 wherein the audio data collected by the audio sensor includes a second audio timestamp, the second audio timestamp further output by the second speaker of the second camera at the incident, the second audio timestamp includes one or more tones that represent the second audio timestamp. ### Claim 8 (depends on 1) The first camera of claim 1 wherein the first camera transfers the audio data to a server. ### Claim 9 (depends on 1) The first camera of claim 1 wherein the first speaker outputs the first audio watermark multiple times while the first camera is positioned at the incident. ### Claim 10 (depends on 1) The first camera of claim 1 wherein the control engine encodes the audio data using a technique that reduces distortion of first audio water mark and the second audio watermark. ### Claim 11 (depends on 1) The first camera of claim 1 wherein at least one of the first audio watermark and the second audio watermark is at least one of preceded by an audio start code and followed by an audio end code. ### Claim 12 (depends on 1) The first camera of claim 1 wherein: the rendering engine renders a first audio synchronization tone, the first audio synchronization tone includes one or more tones that represent the first identifier; the first speaker further outputs the first audio synchronization tone; and the audio data collected by the audio sensor includes the first audio synchronization tone as output by the first speaker. ### Claim 13 (depends on 1) The first camera of claim 1 wherein the audio data includes a second audio synchronization tone, the second audio synchronization tone further output by the second speaker of the second camera at the incident, the second audio synchronization tone includes one or more tones that represent the second identifier. ### Claim 14 A first camera comprising: a video sensor that collects video data at an incident; an audio sensor that collects audio data at the incident; a first speaker; a data store; wherein: the first speaker outputs a first audio watermark, the first audio watermark includes one or more tones that represent a first identifier, the first identifier identifies the first camera; the audio data collected by the audio sensor includes the first audio watermark as output by the first speaker; the audio data collected by the audio sensor includes a second audio watermark, the second audio watermark output by a provided second speaker of a provided second camera at the incident, the second audio watermark includes one or more tones that represent a second identifier of the second camera; and the data store stores the video data and the audio data, including the first audio watermark and the second audio watermark. ### Claim 15 (depends on 14) The first camera of claim 14 wherein the audio data includes a first audio synchronization tone and a second audio synchronization tone collected by the audio sensor, the first audio synchronization tone further output by the first speaker. ### Claim 16 (depends on 14) The first camera of claim 14 wherein at least one of the first audio watermark and the second audio watermark is at least one of preceded by an audio start code and followed by an audio end code. ### Claim 17 (depends on 14) The first camera of claim 14 wherein: the first speaker further outputs a first audio synchronization tone, the first audio synchronization tone includes one or more tones that represent the first identifier; and the audio data collected by the audio sensor includes the first audio synchronization tone as output by the first speaker. ### Claim 18 A first camera comprising: a video sensor that collects video data at an incident; an audio sensor that collects audio data at the incident; a first speaker; a data store; wherein: the first speaker outputs a first audio watermark, the first audio watermark includes one or more tones that represent a first identifier and a first timestamp, the first identifier identifies the first camera; the audio data collected by the audio sensor includes the first audio watermark as output by the first speaker; the audio data collected by the audio sensor includes a second audio watermark, the second audio watermark output by a provided second speaker of a provided second camera at the incident, the second audio watermark includes one or more tones that represent a second identifier and a second timestamp, the second identifier identifies the second camera; and the data store stores the video data and the audio data, including the first audio watermark and the second audio watermark. ### Claim 19 (depends on 18) The first camera of claim 18 wherein at least one of the first audio watermark and the second audio watermark is at least one of preceded by an audio start code and followed by an audio end code.