Claims
- 1. A method of down mixing a plurality of signals including at least a left surround signal, a right surround signal, a left front signal and a right front signal into a stereophonic pair that is a left transmitted signal and a right transmitted signal including,summing the left surround and right surround signals to provide a monophonic surround signal, filtering the monophonic surround signal to provide a filtered monophonic signal having properties related to the diffraction pattern around the head of a listener, multiplying the filtered monophonic surround signal with a right coefficient signal related to the ratio of the magnitude of the right surround signal to the sum of the magnitudes of the left surround signal and the right surround signal to provide a left product signal and multiplying the filtered monophonic surround signal with a left coefficient signal related to the ratio of the magnitude of the left surround signal to the sum of the magnitudes of the left surround signal and the right surround signal to provide a right product signal, combining signals related to the left product signal and the left front signal to provide the left transmitted signal, and combining signals related to the right product signal and the right front signal to provide the right transmitted signal.
- 2. A method of down mixing a plurality of signals including at least a left surround signal, a right surround signal, a left front signal and a right front signal into a stereophonic pair that is a left transmitted signal and a right transmitted signal including,summing the left surround and right surround signals to provide a monophonic surround signal, filtering the monophonic surround signal to provide a filtered monophonic signal having properties related to the diffraction pattern around the head of a listener, multiplying the filtered monophonic signal with a right coefficient signal related to the magnitude of the right surround signal to provide a left product signal, multiplying the filtered monophonic signal with a left coefficient signal related to the magnitude of the left surround signal to provide right product signal, combining signals related to the left product signal and the left front signal to provide the left transmitted signal, and combining signals related to the right product signal and the right front signal to provide the right transmitted signal.
- 3. A method of down mixing a plurality of signals including a left front signal, a right front signal and a surround signal into a stereophonic pair that is a left transmitted signal and a right transmitted signal including,filtering the surround signal to provide a filtered monophonic signal having properties related to the diffraction pattern around the head of a listener, multiplying the filtered monophonic surround signal with a right coefficient signal related the ratio of the magnitude of the right signal to the sum of the magnitudes of the left signal and the right signal to provide a left product signal and multiplying the filtered monophonic signal with a left coefficient signal related to the ratio of the magnitude of the left signal to the sum of the magnitudes of the left signal and the right signal to provide a right product signal, combining signals related to the left product signal and the left front signal to provide the left transmitted signal, and combining signals related to the right product signal and the right front signal to provide the right transmitted signal.
- 4. Apparatus for downmixing a plurality of signals including at least a left surround signal, a right surround signal, a left front signal and a right front signal into a stereophonic pair that is a left transmitted signal and a right transmitted signal comprising,a summer having a left surround input and a right surround input for receiving the left surround signal and right surround signal respectively to provide a monophonic surround signal, a filter coupled to said summer for providing a filtered monophonic signal having properties related to the diffraction pattern around the head of a listener, a left multiplier having one input coupled to the filter and a second input constructed and arranged to receive a right coefficient signal related to the ratio of the magnitude of the right surround signal to the sum of the magnitudes of the left surround signal and the right surround signal to provide a left product signal, a right multiplier having one input coupled to the filter and another input constructed and arranged to receive a left coefficient signal related to the ratio of the magnitude of the left surround signal to the sum of the magnitudes of the left surround signal and the right surround signal to provide a right product signal, a left output combiner having an input coupled to the left multiplier constructed and arranged to receive the left product signal and another input constructed and arranged to receive the left front signal for providing the left transmitted signal, and a right output combiner having one input coupled to the right multiplier constructed and arranged to receive the right product signal and another input constructed and arranged to receive the right front signal for providing the right transmitted signal.
- 5. A method of downmixing a plurality of signals in accordance with claim 1 and further including detecting the magnitude of said left surround signal to provide a left surround magnitude signal,detecting the magnitude of said right surround signal to provide a right surround magnitude signal, combining said left surround magnitude signal and said right surround magnitude signal to form said right coefficient signal and said left coefficient signal, differentially combining the monophonic surround signal with the filtered monophonic signal to provide a differential monophonic signal, differentially combining the filtered monophonic signal with the left product signal to provide a left differential product signal, differentially combining the differential monophonic signal the right product signal to provide a differential right product signal, cumulatively combining the differential monophonic signal with the differential left product signal to provide a left cumulative signal, cumulatively combining the differential monophonic signal with the differential left product signal to provide a cumulative right product signal, cumulatively combining the left front signal with the left cumulative product signal to provide a component of the left transmitted signal, and cumulatively combining the right front signal with the right cumulative product signal to form a component of said right transmitted signal.
- 6. A method of downmixing a plurality of signals in accordance with claim 5 wherein said plurality of signals further includes a center front signal and further including,cumulatively combining said center front signal with said left front signal and said cumulative left product signal to form a component of said left transmitted signal, and cumulatively combining said center front signal and said right front signal while differentially combining said cumulative right product signal to form a component of said right transmitted signal.
- 7. A method of downmixing a plurality of signals in accordance with claim 1 and further including,detecting the magnitude of said left surround signal to provide a left surround magnitude signal, detecting the magnitude of said right surround signal to provide a right surround magnitude signal, combining said left surround magnitude signal and said right magnitude surround signal to provide said right coefficient signal and said left coefficient signal, differentially combining said left product signal with said monophonic signal to provide a differential left surround signal, differentially combining said right product signal and said monophonic surround signal to provide a differential right surround signal, cumulatively combining said left front signal and said differential left product signal to provide a component of said left transmitted signal, and differentially combining said differential right product signal with said right front signal to provide a component of said right transmitted signal.
- 8. A method of downmixing a plurality of signals in accordance with claim 7 wherein said plurality of signals also include a center front signal and further including,cumulatively combining said center front signal with said left front signal and said differential left surround signal to form a component of said left transmitted signal, and cumulatively combining said center front signal with said right front signal differentially combined with differential right product signal to form a component of said right transmitted signal.
- 9. A method of downmixing a plurality of signals including at least a left surround signal, a right surround signal, a left front signal and a right front signal into a stereophonic pair that is a left transmitted signal and a right transmitted signal including,summing the left surround and right surround signals to provide a monophonic surround signal, filtering the monophonic surround signal to provide a filtered monophonic signal having properties related to the diffraction pattern around the head of a listener, and multiplying the filtered monophonic surround signal with a time varying coefficient signal related to the surround signals.
- 10. A method of downmixing a plurality of signals in accordance with claim 1 wherein said coefficient signal is related to the magnitude of the larger of the magnitudes of said left and right surround signals.
- 11. A method of downmixing a plurality of signals in accordance with claim 1 wherein the steps of combining signals relating to the left product signal and the left front signal and combining signals related to the right product signal and the right front signal is performed acoustically to provide the left and right transmitted signals as left transmitted sound signals and right transmitted sound signals respectively.
Parent Case Info
This application is a continuing application of U.S. application Ser. No. 08/796,285, filed Feb. 7, 1997, entitled SURROUND SOUND CHANNEL ENCODING AND DECODING.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
5579396 |
Iida et al. |
Nov 1996 |
A |
Foreign Referenced Citations (3)
Number |
Date |
Country |
54123902 |
Sep 1979 |
JP |
06165079 |
Oct 1994 |
JP |
9820709 |
May 1998 |
WO |
Continuations (1)
|
Number |
Date |
Country |
Parent |
08/796285 |
Feb 1997 |
US |
Child |
09/122988 |
|
US |