Method and apparatus for synchronizing midi data stored in sub-channel of CD-ROM disc main channel audio data
US5450597A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 12, 1991 |
| Grant date | Sep 12, 1995 |
| Priority date | — |
| Expiry date | Dec 12, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/2545
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for ensuring that MIDI data stored in the subcode channel area of a compact disc is synchronized with the main channel audio of the compact disc. Synchronization problems have been created when transferring audio on a tape from an audio studio to a PCM 1630 tape which is to be used as a compact disc master resulting in a squashing or stretching of the audio data with respect to the MIDI data. One reason this can occur is because F-1 tape records and plays back at 29.97 frames per second while PCM 1630 tape records and plays back at 30 frames per second. The result is that even if the MIDI data and main channel audio data begin in sync, they lose sync during transfers and may drift apart linearly over time as well as be offset with respect to each other. The present invention corrects such synchronization problems by playback simulation, MIDI data/Main channel audio sync measurement and MIDI data adjustment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.