Audio matrix encoding
US5862228A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 21, 1997 |
| Grant date | Jan 19, 1999 |
| Priority date | — |
| Expiry date | Feb 21, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04S3/02
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A surround sound encoder, intended for implementation in software, runs in real time on a personal computer using low mips and a small fraction of available CPU cycles. In the principal application for the encoder, the Lt and Rt signals of the encoder are mixed with the Lt and Rt signals of a pre-recorded source (e.g., computer game soundtrack, CD ROM, Internet audio, etc.). Alternatively, the encoder may be used by itself or with one or more other virtual encoders to provide a totally user-generated soundfield. The encoder is implemented in either of two ways: the signal being encoded may be panned to one or more of the four inputs of a surround-sound fixed matrix encoder or the signal may be encoded by applying the signal to a surround-sound variable-matrix encoder. Phase shifting, required in the encoder, is achieved by applying a signal to two phase-shifting processes, producing two signals whose relative phase difference is sufficiently close to the desired phase shift over at least a substantial part of the frequency band of interest. Satisfactory audible results may be achieved, using very low computer processing power, when one of the phase shifting processes is implemented…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.