# US 8,542,749 B2 · Method and apparatus for measuring audiovisual synchronisation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,542,749 B2 - Document ID: US8542749B2 - Status: Granted - Kind: B2 - Application number: 13/140,681 - Filed: 2008-12-17 - Published: 2012-03-08 - Granted: 2013-09-24 - Earliest claimed: 2008-12-17 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Sally Bush - Inventors: Sally Bush - Web page: https://patentgrep.com/patent/US8542749B2 ## CPC - H04N 5/04: Synchronising (for television systems using pulse code modulation H04N7/56) - H04N 17/02: for colour television signals - H04N 21/2368: Multiplexing of audio and video streams - H04N 21/4305: {Synchronising client clock from received content stream, e.g. locking decoder clock with encoder clock, extraction of the PCR packets (arrangements for synchronising receiver with transmitter by comparing receiver clock with transmitter clock H04L7/0012; arrangements for synchronising receiver with transmitter wherein the receiver takes measures against momentary loss of synchronisation H04L7/0083)} - H04N 21/43072: {of multiple content streams on the same device} - H04N 21/4341: {Demultiplexing of audio and video streams} - H04N 21/4394: {involving operations for analysing the audio stream, e.g. detecting features or characteristics in audio streams (arrangements characterised by components specially adapted for monitoring, identification or recognition of audio in broadcast systems H04H60/58)} - H04N 21/44008: {involving operations for analysing video streams, e.g. detecting features or characteristics in the video stream (arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59)} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract There is provided a method of measuring audiovisual synchronization between at least one encoded audio stream and at least one encoded video stream, comprising measuring the time of input into an audio encoder of source audio data to be encoded into said encoded audio stream, measuring the time of input into a video encoder of source video data to be encoded into said encoded video stream, determining a Presentation Time Stamp value, indicative of a time of presentation, for each of the respective at least one encoded audio stream and at least one encoded video stream, and transmitting a measured audio input time, a measured video input time and presentation time stamp values to a downstream component. There is also provided an apparatus and system for measuring audiovisual synchronization between at least one encoded audio stream and at least one encoded video stream. ## Claims ### Claim 1 A method of measuring audiovisual synchronisation between at least one encoded audio strewn and at least one encoded video stream, comprising: measuring the time of input into an audio encoder of source audio data to be encoded into said encoded audio stream; measuring the time of input into a video encoder of source video data to be encoded into said encoded video stream; determining a Presentation Time Stamp value, indicative of a time of presentation, for each of the respective at least one encoded audio stream and at least one encoded video stream; and transmitting the measured audio input time, the measured video input time, and the presentation time stamp values to a downstream component. ### Claim 2 (depends on 1) The method of claim 1, wherein the time of input into an audio encoder of source audio data to be encoded into said encoded audio stream and the time of input into a video encoder of source video data to be encoded into said encoded video stream are measured using a clock also used to produce the Presentation Time Stamp value. ### Claim 3 (depends on 2) The method of claim 2, wherein the clock is the encoder system clock. ### Claim 4 (depends on 1) The method of claim 1, wherein the Presentation Time Stamp value is determined according to one or more digital compression standards in use to compress the encoded audio stream and encoded video stream. ### Claim 5 (depends on 1) The method of claim 1, wherein the measured audio input time and the measured video input time are inserted into a transport stream containing the encoded audio stream and encoded video stream, for use by downstream components in determining the delay of an upstream audio and video encoder pair. ### Claim 6 (depends on 5) The method of claim 5, wherein downstream components display said measured audio input time and the measured video input time. ### Claim 7 (depends on 1) The method of claim 1, wherein each at least one encoded audio stream and at least one encoded video stream comprises a corresponding audiovisual pair to be presented in synchronisation. ### Claim 8 (depends on 1) Apparatus for measuring audiovisual synchronisation between at least one encoded audio stream and at least one encoded video stream, comprising: a delay calculation unit confirmed to measure audiovisual synchronisation according to claim 1; and a private data encoder confirmed to encode data indicative of the measured audiovisual synchronisation into a transport stream. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein the apparatus is an audiovisual encoder. ### Claim 10 (depends on 9) A system for measuring audiovisual synchronisation between at least one encoded audio stream and at least one encoded video stream and outputting a measured audiovisual synchronisation value, comprising: the encoder apparatus of claim 9; and a decoder apparatus comprising a private data decoder adapted to decode private data in a audiovisual transport stream containing said data indicative of the measured audiovisual synchronisation. ### Claim 11 (depends on 1) The method of claim 1, wherein the audiovisual synchronisation value is inserted into a transport stream containing the encoded audio stream and encoded video stream, for use by downstream components in determining the delay of an upstream audio and video encoder pair. ### Claim 12 (depends on 11) The method of claim 11, wherein downstream components display said audiovisual synchronisation value. ### Claim 13 (depends on 11) The method of claim 11, wherein downstream components use said audiovisual synchronisation value to automatically re-align the encoded audio stream and the encoded video stream. ### Claim 14 A method of measuring audiovisual synchronisation between at least one encoded audio stream and at least one encoded, video stream, comprising: measuring the time of input into an audio encoder of source audio data to be encoded into said encoded audio stream; measuring the time of input into a video encoder of source video data to be encoded into said encoded video strewn; determining a time of presentation value for each of the respective at least one encoded audio stream and at least one encoded video stream; calculating a difference between the time of presentation and the measured time of input for each of the at least one encoded audio stream and at least one encoded video stream; and determining an audiovisual synchronisation value from the calculated difference. ### Claim 15 (depends on 14) The method of claim 14, wherein the step of determining an audiovisual synchronisation value comprises: subtracting the calculated difference between the time of presentation and the measured time of input for the encoded audio stream from the calculated difference between the time of presentation and the measured time of input for the encoded video stream. ### Claim 16 (depends on 14) The method of claim 14, wherein the time of input into an audio encoder of source audio data to be encoded into said encoded audio stream and the time of input into a video encoder of source video data to be encoded into said encoded video stream are measured using a clock also used to produce the time of presentation value. ### Claim 17 (depends on 16) The method of claim 16, wherein the clock is the encoder system clock. ### Claim 18 (depends on 14) The method of claim 14, wherein the time of presentation value is determined according to one or more digital compression standards in use to compress the encoded audio stream and encoded video stream. ### Claim 19 (depends on 14) The method of claim 14, wherein each at least one encoded audio stream and at least one encoded video stream comprises a corresponding audiovisual pair to be presented in synchronisation. ### Claim 20 (depends on 14) Apparatus for measuring audiovisual synchronisation between at least one encoded, audio stream and at least one encoded video stream, comprising: a delay calculation unit confirmed to measure audiovisual synchronisation according to claim 14; and a private data encoder confirmed to encode data indicative of the measured audiovisual synchronisation into a transport stream. ### Claim 21 (depends on 20) The apparatus of claim 20, wherein the apparatus is an audiovisual encoder. ### Claim 22 (depends on 21) A system for measuring audiovisual synchronisation between at least one encoded audio stream and at least one encoded video stream and outputting a measured audiovisual synchronisation value, comprising: the encoder apparatus of claim 21; and a decoder apparatus comprising a private data decoder adapted to decode private data in a audiovisual transport stream containing said data indicative of the measured audiovisual synchronisation.