High-band residual prediction with time-domain inter-channel bandwidth extension

1. A device comprising a decoder configured to receive, via a receiver, a bitstream that includes at least an encoded mid signal, the decoder including:

a high-band residual prediction unit configured to process a time-domain decoded high-band mid signal to generate a time-domain high-band residual prediction signal, the time-domain decoded high-band mid signal based on the encoded mid signal; and

an inter-channel bandwidth extension decoder configured to generate a high-band left channel and a high-band right channel based on the time-domain decoded high-band mid signal and the time-domain high-band residual prediction signal.

2. The device of claim 1 , wherein the high-band residual prediction unit comprises:

one or more all-pass filters configured to generate a filtered time-domain signal by filtering the time-domain decoded high-band mid signal; and

a gain mapper configured to generate the time-domain high-band residual prediction signal by performing a gain mapping operation on the filtered time-domain signal.

3. The device of claim 1 , wherein the high-band residual prediction unit is further configured to:

generate a spectrally-mapped signal by performing a spectral mapping operation on the time-domain decoded high-band mid signal; and

generate the time-domain high-band residual prediction signal by filtering the spectrally-mapped signal.

4. The device of claim 1 , further comprising:

a low-band mid signal decoder configured to decode a low-band portion of the encoded mid signal to generate a decoded low-band mid signal;

a low-band residual prediction unit configured to process the decoded low-band mid signal to generate a low-band residual prediction signal;

an up-mix processor configured to generate a low-band left channel and a low-band right channel based partially on the decoded low-band mid signal and the low-band residual prediction signal; and

a high-band mid signal decoder configured to decode a high-band portion of the encoded mid signal to generate the time-domain decoded high-band mid signal.

5. The device of claim 4 , comprising the receiver, wherein the bitstream further includes one or more parameters and a reference channel indicator, the one or more parameters comprising a residual prediction gain, wherein the up-mix processor is further configured to generate the low-band left channel and the low-band right channel at least partially based on the one or more parameters and the reference channel indicator.

6. The device of claim 4 , further comprising:

a first combination circuit configured to combine the low-band left channel and the high-band left channel to generate a left channel;

a second combination circuit configured to combine the low-band right channel and the high-band right channel to generate a right channel; and

an output device configured to output the left channel and the right channel.

7. The device of claim 6 , wherein the inter-channel bandwidth extension decoder comprises:

a high-band residual generation unit configured to apply a residual prediction gain to the time-domain high-band residual prediction signal to generate a high-band residual channel; and

a third combination circuit configured to combine the time-domain decoded high-band mid signal and the high-band residual channel to generate a high-band reference channel.

8. The device of claim 7 , wherein the inter-channel bandwidth extension decoder further comprises:

a first spectral mapper configured to perform a first spectral mapping operation on the time-domain decoded high-band mid signal to generate a spectrally-mapped high-band mid signal; and

a second spectral mapper configured to perform a second spectral mapping operation on the high-band residual channel to generate a spectrally-mapped high-band residual channel.

9. The device of claim 7 , wherein the inter-channel bandwidth extension decoder further comprises a first gain mapper configured to perform a first gain mapping operation on the time-domain decoded high-band mid signal to generate a first high-band gain-mapped channel.

10. The device of claim 9 , wherein the inter-channel bandwidth extension decoder further comprises a second gain mapper configured to perform a second gain mapping operation on the high-band residual channel to generate a second high-band gain-mapped channel.

11. The device of claim 10 , wherein the inter-channel bandwidth extension decoder further comprises:

a fourth combination circuit configured to combine the first high-band gain-mapped channel and the second high-band gain-mapped channel to generate a high-band target channel; and

a channel selector configured to:

receive a reference channel indicator; and

based on the reference channel indicator:

designate one of the high-band reference channel or the high-band target channel as the high-band left channel; and

designate the other of the high-band reference channel or the high-band target channel as the high-band right channel.

12. The device of claim 1 , wherein the high-band residual prediction unit comprises a gain mapper configured to generate the time-domain high-band residual prediction signal by performing a gain mapping operation on a second time-domain signal, the second time-domain signal based on the time-domain decoded high-band mid signal.

13. The device of claim 1 , wherein the high-band residual prediction unit and the inter-channel bandwidth extension decoder are integrated into a base station or a mobile device.

14. A method comprising:

receiving, at a decoder, a bitstream that includes at least an encoded mid signal;

processing, at the decoder, a time-domain decoded high-band mid signal to generate a time-domain high-band residual prediction signal, the time-domain decoded high-band mid signal based on the encoded mid signal; and

generating, at the decoder, a high-band left channel and a high-band right channel based on the time-domain decoded high-band mid signal and the time-domain high-band residual prediction signal.

15. The method of claim 14 , further comprising:

decoding, at the decoder, a low-band portion of the encoded mid signal to generate a decoded low-band mid signal;

processing, at the decoder, the decoded low-band mid signal to generate a low-band residual prediction signal;

generating, at the decoder, a low-band left channel and a low-band right channel based partially on the decoded low-band mid signal and the low-band residual prediction signal; and

decoding, at the decoder, a high-band portion of the encoded mid signal to generate the time-domain decoded high-band mid signal.

16. The method of claim 15 , further comprising:

combining, at the decoder, the low-band left channel and the high-band left channel to generate a left channel; and

combining, at the decoder, the low-band right channel and the high-band right channel to generate a right channel.

17. The method of claim 15 , further comprising:

performing, at the decoder, a first transform operation on the low-band residual prediction signal to generate a frequency-domain low-band residual prediction signal; and

performing, at the decoder, a second transform operation on the decoded low-band mid signal to generate a frequency-domain low-band mid signal.

18. The method of claim 17 , further comprising:

receiving, at the decoder, one or more parameters and a reference channel indicator, the one or more parameters comprising a residual prediction gain; and

generating, at the decoder, the low-band left channel and the low-band right channel based on the one or more parameters, the reference channel indicator, the frequency-domain low-band residual prediction signal, and the frequency-domain low-band mid signal.

19. The method of claim 15 , further comprising:

applying, at the decoder, a residual prediction gain to the time-domain high-band residual prediction signal to generate a high-band residual channel; and

combining, at the decoder, the time-domain decoded high-band mid signal and the high-band residual channel to generate a high-band reference channel.

20. The method of claim 19 , further comprising:

performing, at the decoder, a first spectral mapping operation on the time-domain decoded high-band mid signal to generate a spectrally-mapped high-band mid signal; and

performing, at the decoder, a first gain mapping operation on the spectrally-mapped high-band mid signal to generate a first high-band gain-mapped channel.

21. The method of claim 20 , further comprising:

performing, at the decoder, a second spectral mapping operation on the high-band residual channel to generate a spectrally-mapped high-band residual channel; and

performing, at the decoder, a second gain mapping operation on the spectrally-mapped high-band residual channel to generate a second high-band gain-mapped channel.

22. The method of claim 21 , further comprising:

combining, at the decoder, the first high-band gain-mapped channel and the second high-band gain-mapped channel to generate a high-band target channel;

receiving a reference channel indicator at the decoder; and

based on the reference channel indicator:

designating, at the decoder, one of the high-band reference channel or the high-band target channel as the high-band left channel; and

designating, at the decoder, the other of the high-band reference channel or the high-band target channel as the high-band right channel.

23. The method of claim 14 , wherein processing the time-domain decoded high-band mid signal comprises scaling the time-domain decoded high-band mid signal.

24. The method of claim 14 , wherein processing the time-domain decoded high-band mid signal comprises filtering the time-domain decoded high-band mid signal.

25. The method of claim 14 , further comprising performing, at the decoder, a spectral mapping operation on the time-domain decoded high-band mid signal to generate a spectrally-mapped signal, the time-domain high-band residual prediction signal based on the spectrally-mapped signal.

26. The method of claim 14 , wherein processing the time-domain decoded high-band mid signal is performed at a base station or a mobile device.

27. A non-transitory computer-readable medium comprising instructions that, when executed by a processor within a decoder, cause the processor to perform operations comprising:

receiving, at a decoder, a bitstream that includes at least an encoded mid signal;

processing, at the decoder, a time-domain decoded high-band mid signal to generate a time-domain high-band residual prediction signal, the time-domain decoded high-band mid signal based on the encoded mid signal; and

generating, at the decoder, a high-band left channel and a high-band right channel based on the time-domain decoded high-band mid signal and the time-domain high-band residual prediction signal.

28. The non-transitory computer-readable medium of claim 27 , wherein the operations further comprise:

decoding, at the decoder, a low-band portion of an encoded mid signal to generate a decoded low-band mid signal; and

generating, at the decoder, a low-band left channel and a low-band right channel based partially on the decoded low-band mid signal.

29. An apparatus comprising:

means for receiving, at a decoder, a bitstream that includes at least an encoded mid signal;

means for processing, at the decoder, a time-domain decoded high-band mid signal to generate a time-domain high-band residual prediction signal, the time-domain decoded high-band mid signal based on the encoded mid signal; and

means for generating, at the decoder, a high-band left channel and a high-band right channel based on the time-domain decoded high-band mid signal and the time-domain high-band residual prediction signal.

30. The apparatus of claim 29 , wherein the means for processing is integrated into a base station or a mobile device.