Synchronization of digital video with digital audio

• US 5,557,423 A
• Filed: 11/23/1994
• Issued: 09/17/1996
• Est. Priority Date: 04/16/1993
• Status: Expired due to Term

• Current Assignee: Avid Technology Incorporated
• Original Assignee: Avid Technology Incorporated
• Inventors: Phillips, Michael, O'Connor, Patrick, Peters, Eric
• Primary Examiner(s): Chin, Tommy P.
• Assistant Examiner(s): Truong, Khoi
• Application Number:
  US08/344,409
• Time in Patent Office: 664 Days
• Field of Search: 358/335, 358/311, 358/341, 358/343, 358/337, 358/339, 360/33.1, 360/13, 360/14.1, 360/14.2, 360/14.3, 360/27, 360/32
• US Class Current: 386/201
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 27/002 Programmed access in sequence to a plurality of record carriers or indexed parts, e.g. tracks, thereof, e.g. for editing; transfer of record carriers from magazine G11B15/68, G11B17/10; G11B17/22
• CPC Class Codes: G11B 27/031 Electronic editing of digitised analogue information signals, e.g. audio or video signals
• CPC Class Codes: G11B 27/06 Cutting and rejoining; Notching, or perforating record carriers otherwise than by recording styli record carriers with provision for splicing G11B23/20
• CPC Class Codes: G11B 27/10 Indexing; Addressing; Timing or synchronising; Measuring tape travel
• CPC Class Codes: G11B 27/11 by using information not detectable on the record carrier
• CPC Class Codes: G11B 27/24 by sensing features on the record carrier other than the transducing track ; sensing signals or marks recorded by another method than the main recording
• CPC Class Codes: G11B 27/323 Time code signal, e.g. on a cue track as SMPTE- or EBU-time code
• CPC Class Codes: H04N 5/85 on discs or drums
• CPC Class Codes: H04N 5/926 by pulse code modulation H04N5/919 takes precedence
• CPC Class Codes: H04N 5/9265 with processing of the sound signal
• CPC Class Codes: H04N 5/9267 using time division multiplex of the PCM audio and PCM video signals

Abstract

A method of synchronizing digitized audio information and digitized picture information establishes a reference time base based on timecodes included with the audio and picture information. The reference time base may be used to synchronize output between a digitized source and one which may be digitized or undigitized.

Claims

1. A method of synchronizing a plurality of streams of digitized audio/visual data including corresponding streams of absolute time indications with each other, comprising the steps of:

creating digital reference time base including periodic timing information and a predetermined start time;

identifying a first relationship between the periodic timing information and a first stream of absolute time indicators that corresponds to a first stream of the plurality of streams of digitized audio/visual data, such that the predetermined start time is coincident with a start time of the first stream of absolute time indicators;

identifying a second relationship between the periodic timing information and a second stream of absolute time indicators that corresponds to a second stream of the plurality of streams of digitized audio/visual data, such that the predetermined start time is coincident with a start time of the second stream of absolute time indicators; and

outputting the first and second streams of digitized audio/visual data corresponding to the digital reference time base in accordance with the first relationship and the second relationship, so that the first and second streams of digitized audio/visual data are synchronized.