Method, medium, and system for generating a stereo signal
Surround audio decoding for selectively generating an audio signal from a multi-channel signal. In the surround audio decoding, a down-mixed signal, e.g., as down-mixed by an encoding terminal, is selectively up-mixed to a stereo signal or a multi-channel signal, by generating spatial information for generating the stereo signal, using spatial information for up-mixing the down-mixed signal to the multi-channel signal.
1. A method for generating a stereo signal, comprising:
calculating, using at least one processor, first spatial information for up-mixing a down-mixed mono signal to the stereo signal, using second spatial information for up-mixing the down-mixed mono signal to a multi-channel signal other than the stereo signal; and
up-mixing the down-mixed mono signal to the stereo signal using the calculated first spatial information for up-mixing the down-mixed mono signal to the stereo signal,
wherein the second spatial information for up-mixing the down-mixed mono signal to the multi-channel signal other than the stereo signal pre-exists as being generated by an encoder that generates the down-mixed mono signal.
2. The method of claim 1 , wherein the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal includes information about an energy ratio or difference between predetermined channels in multi-channels.
3. The method of claim 2 , wherein the calculating of the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal comprises:
summing an energy sum of multi-channels corresponding to a left channel with a value obtained by multiplying energy of a front center channel by a predetermined value, as a left channel sum;
summing an energy sum of multi-channels corresponding to a right channel with a value obtained by multiplying energy of a front center channel by another predetermined value, as a right channel sum; and
calculating the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal using a ratio of the left and right channel sums.
4. The method of claim 3 , wherein in the calculating of the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal, the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal is calculated using the following equation:
CLD′=( P FL +P BL +a*P FC )/( P FR +P BR +b*P FC )
where CLD′ is an energy ratio between channels included in the calculated first spatial information, PFL denotes energy of a front left (FL) channel, PBL denotes energy of a back left (BL) channel, PFC denotes energy of a front center (FC) channel, PFR denotes energy of a front right (FR) channel, PBR denotes energy of a back right (BR) channel, a and b are constants, and the * represents a multiplication operation.
5. The method of claim 1 , wherein the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal includes information about correlation or coherence between predetermined channels in multi-channels.
6. The method of claim 5 , wherein, in the calculating of the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal, the first spatial information for the up-mixing the down-mixed mono signal to the stereo signal is calculated by linear interpolation, using the correlation or coherence between the predetermined channels in the multi-channels.
7. The method of claim 6 , wherein, in the calculating of the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal, the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal is calculated using the following equation:
ICC′=α*ICC a +(1×α)*ICC b
where ICC′ denotes the correlation or coherence between the predetermined channels, ICCx denotes correlation or coherence of an OTTx module, a is a constant, α represents a value, and the * represents a multiplication operation.
8. The method of claim 6 , wherein, in the calculating of the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal, the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal is calculated by searching within a table storing spatial information about an energy ratio or difference between the predetermined channels in the multi-channels or spatial information corresponding to the correlation or coherence between the predetermined channels in the multi-channels.
9. The method of claim 1 , further comprising applying temporal processing (TP) or temporal envelope shaping (TES) to the stereo signal.
10. A method for generating an audio signal, comprising:
selectively up-mixing a down-mixed mono signal to at least one of a multi-channel signal and a stereo signal,
wherein up-mixing of the down-mixed mono signal to the multi-channel signal is accomplished through multi-staged up-mixings of the down-mixed mono signal based upon first spatial information for up-mixing the down-mixed mono signal to the multi-channel signal, and
wherein up-mixing of the down-mixed mono signal to the stereo signal is accomplished by calculating, using at least one processor, second spatial information for the up-mixing of the down-mixed mono signal to the stereo signal based on the first spatial information for up-mixing the down-mixed mono signal to the multi-channel signal, and by applying the calculated second spatial information to a single-staged up mixing to up-mix the down-mixed mono signal to the stereo signal differently from any stage of the multi-staged up-mixings of the down-mixed mono signal to any multi-channel signal in the up-mixing of the down-mixed mono signal to the multi-channel signal.
11. The method of claim 10 , wherein selection of the up-mixing of the down-mixed mono signal to the at least one of the multi-channel signal and the stereo signal is based upon a number of speakers available in a corresponding decoding system or locations of available speakers among speakers included in the corresponding decoding system.
12. A method for generating an audio signal, comprising:
selectively up-mixing a down-mixed mono signal to at least one of a multi-channel signal and a stereo signal,
wherein up-mixing of the down-mixed mono signal to the multi-channel signal is accomplished through a multi-staged up-mixing of the down-mixed mono signal based upon first spatial information for up-mixing the down-mixed mono signal to the multi-channel signal, and
wherein up-mixing of the down-mixed mono signal to the stereo signal is accomplished by calculating, using at least one processor, second spatial information for the up-mixing of the down-mixed mono signal to the stereo signal based on the first spatial information for up-mixing the down-mixed mono signal to the multi-channel signal, and by applying the calculated second spatial information to a single stage to up-mix the down-mixed mono signal to the stereo signal, wherein the first spatial information for the up-mixing of the down-mixed mono signal to the multi-channel signal pre-exists as being generated by an encoder that generates the down-mixed mono signal.
13. At least one non-transitory computer readable medium comprising computer readable code to control at least one processing element to implement the method of claim 1 .
14. At least one non-transitory computer readable medium comprising computer readable code to control at least one processing element to implement the method of claim 10 .
15. A system for generating a stereo signal, comprising:
a spatial information generator to calculate first spatial information for up-mixing a down-mixed mono signal to the stereo signal, using second spatial information for up-mixing the down-mixed mono signal to a multi-channel signal other than the stereo signal; and
an up-mixing unit to up-mix the down-mixed mono signal to the stereo signal, using the calculated first spatial information for up-mixing the down-mixed mono signal to the stereo signal,
wherein the second spatial information for up-mixing the down-mixed mono signal to the multi-channel signal other than the stereo signal pre-exists as being generated by an encoder that generates the down-mixed mono signal.
16. The system of claim 15 , wherein the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal includes information about an energy ratio or difference between predetermined channels in multi-channels.
17. The system of claim 16 , wherein the spatial information generator comprises:
a first summing unit to sum an energy sum of channels corresponding to a left channel with a value obtained by multiplying energy of a front center channel by a predetermined value, as a left channel sum;
a second summing unit summing an energy sum of channels corresponding to a right channel with a value obtained by multiplying energy of a front center channel by another predetermined value, as a right channel sum; and
an information generator calculating the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal using a ratio of the left and right channel sums.
18. The system of claim 17 , wherein the spatial information generator calculates the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal, using the following equation:
CLD′=( P FL +P BL +α*P FC )/( P FR +P BR +b*P FC )
where CLD′ denotes an energy ratio between channels included in the calculated first spatial information, PFL denotes energy of a front left (FL) channel, PBL denotes energy of a back left (BL) channel, PFC denotes energy of a front center (FC) channel, PFR denotes energy of a front right (FR) channel, PBR denotes energy of a back right (BR) channel, a and b are constants, and the * represents a multiplication operation.
19. The system of claim 15 , wherein the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal includes information about correlation or coherence between predetermined channels in multi-channels.
20. The system of claim 19 , wherein the spatial information generator calculates the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal, by linear interpolation, using the correlation or coherence between the predetermined channels in the multi-channels.
21. The system of claim 20 , wherein the spatial information generator calculates the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal, using the following equation:
ICC′=α*ICC a +(1×α)*ICC b
where ICC′ denotes the correlation or coherence between the predetermined channels, ICC 0 denotes correlation or coherence of an OTTx module, a is a constant, a represents a value, and the * represents a multiplication operation.
22. The system of claim 19 , wherein the spatial information generator calculates the first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal, by searching for spatial information about an energy ratio or difference between the predetermined channels in the multi-channels or correlation or coherence between the predetermined channels in the multi-channels, from a table storing the spatial information about the energy ratio or difference between the predetermined channels in the multi-channels or the spatial information corresponding to the correlation or coherence between the predetermined channels in the multi-channels.
23. The system of claim 15 , further comprising a TP/TES applying unit to apply temporal processing (TP) or temporal envelope shaping (TES) to the stereo signal.
24. An system for generating an audio signal, comprising:
a plurality of up-mixing modules to selectively up-mix a down-mixed mono signal to at least one of a stereo signal and a multi-channel signal; and
a spatial information generator to calculate first spatial information for up-mixing the down-mixed mono signal to the stereo signal, using second spatial information for up-mixing the down-mixed mono signal to the multi-channel signal,
wherein up-mixing of the down-mixed mono signal to the multi-channel signal is accomplished through multi-staged up-mixings by the plurality of up-mixing modules based upon the second spatial information for up-mixing the down-mixed mono signal to the multi-channel signal, and
wherein up-mixing of the down-mixed mono signal to the stereo signal is accomplished through a single-staged up-mixing by one of the plurality of up-mixing modules based upon the calculated first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal differently from any stage of the multi-staged up-mixings of the down-mixed mono signal to any multi-channel signal in the up-mixing of the down-mixed mono signal to the multi-channel signal.
25. The system of claim 24 , wherein the selection of the up-mixing of the down-mixed mono signal to at least one of the multi-channel signal and the stereo signal is based upon a number of speakers available in a corresponding decoding system or locations of available speakers among speakers included in the corresponding decoding system.
26. A system for generating an audio signal, comprising:
a plurality of up-mixing modules to selectively up-mix a down-mixed mono signal to at least one of a stereo signal and a multi-channel signal; and
a spatial information generator to calculate first spatial information for up-mixing the down-mixed mono signal to the stereo signal, using second spatial information for up-mixing the down-mixed mono signal to the multi-channel signal,
wherein up-mixing of the down-mixed mono signal to the multi-channel signal is accomplished through staged up-mixing by the plurality of up-mixing modules based upon the second spatial information for up-mixing the down-mixed mono signal to the multi-channel signal, and
wherein up-mixing of the down-mixed mono signal to the stereo signal is accomplished through a single up-mixing by one of the plurality of up-mixing modules based upon the calculated first spatial information for the up-mixing of the down-mixed mono signal to the stereo signal, wherein the second spatial information for the up-mixing of the down-mixed mono signal to the multi-channel signal pre-exists as being generated by an encoder that generates the down-mixed mono signal.
27. A method for generating a stereo signal, comprising:
calculating, using at least one processor, first information including channel level differences and inter-channel correlation for up-mixing a down-mixed mono signal to the stereo signal, based on second information including channel level differences and inter-channel correlation for up-mixing a multi-channel signal, other than the stereo signal, from a down-mixed mono signal; and
up mixing the down-mixed mono signal transmitted from the encoder to the stereo signal using the calculated first information including the channel level differences and the inter-channel correlation.
28. A method for generating a stereo signal, comprising:
calculating, using at least one processor, first spatial information for up-mixing a down-mixed mono signal to the stereo signal, based on second spatial information for up-mixing a down-mixed mono signal to a multi-channel signal other than the stereo signal, and including channel level differences and inter-channel correlation; and
up-mixing the down-mixed mono signal to the stereo signal by an OTT module, using the calculated first spatial information,
wherein the calculated first spatial information is obtained from a power ratio between a first power and second power, and the first power is calculated using power of a front left channel, power of a back left channel, and power of a front center channel of the multi-channel signal, and the second power is calculated using power of a front right channel, power of a back right channel, and the power of the front center channel of the multi-channel signal.
29. A method for generating a stereo signal from a down-mixed mono signal, the method comprising:
calculating, using at least one processor, first spatial parameters for up-mixing the down-mixed mono signal to the stereo signal, based on second spatial parameters for up-mixing the down-mixed mono signal to a multi-channel signal other than the stereo signal which are used; and
generating the stereo signal from the down-mixed mono signal by using the first spatial parameters.
30. The method of claim 29 , wherein the first spatial parameters include Channel Level Difference (CLD) and Inter-Channel Correlation (ICC).
31. The method of claim 30 , wherein the CLD included in the first spatial parameters is calculated by using a power ratio between a first power and a second power,
wherein the first power is obtained using power of a front left channel, power of a back left channel and power of a front center channel, of the multi-channel signal and
the second power is obtained using power of a front center channel, power of a front right channel and power of a back right channel, of the multi-channel signal.