Coding of multiple audio signals

1. A device comprising:

a down-mixer configured to perform a down-mix operation, based on a frequency-domain reference channel and a frequency-domain target channel, to generate a mid channel and a side channel;

a residual generation unit configured to:

generate a predicted side channel based on the mid channel, the predicted side channel corresponding to a prediction of the side channel; and

generate a residual channel based on the side channel and the predicted side channel;

a residual scaling unit configured to:

determine a scaling factor based on a temporal misalignment between the frequency-domain reference channel and the frequency-domain target channel; and

scale the residual channel by the scaling factor to generate a scaled residual channel; and

a residual channel encoder configured to encode the scaled residual channel as part of a bitstream.

2. The device of claim 1 , further comprising a stereo channel adjustment unit configured to determine an inter-channel mismatch value, the inter-channel mismatch value indicative of the temporal misalignment between the frequency-domain reference channel and the frequency-domain target channel, wherein the residual scaling unit is configured to determine the scaling factor based on the inter-channel mismatch value.

3. The device of claim 2 , wherein the stereo channel adjustment unit is further configured to adjust the frequency-domain target channel based on the inter-channel mismatch value to generate an adjusted frequency-domain target channel, and wherein the down-mixer is configured to perform the down-mix operation on the frequency-domain reference channel and the adjusted frequency-domain target channel to generate the mid channel and the side channel.

4. The device of claim 2 , wherein the residual scaling unit is further configured to determine a residual gain parameter based on the inter-channel mismatch value.

5. The device of claim 2 , wherein one or more bands of the residual channel are zeroed out based on the inter-channel mismatch value.

6. The device of claim 2 , wherein each band of the residual channel is zeroed out based on the inter-channel mismatch value.

7. The device of claim 2 , wherein the residual channel encoder is further configured to set a number of bits used to encode the residual channel in the bitstream based on the inter-channel mismatch value.

8. The device of claim 2 , wherein the residual channel encoder is further configured to compare the inter-channel mismatch value to a threshold.

9. The device of claim 8 , wherein, if the inter-channel mismatch value is less than or equal to the threshold, a first number of bits is used to encode the scaled residual channel.

10. The device of claim 9 , wherein, if the inter-channel mismatch value is greater than the threshold, a second number of bits is used to encode the scaled residual channel.

11. The device of claim 10 , wherein the second number of bits is different from the first number of bits.

12. The device of claim 10 , wherein the second number of bits is less than the first number of bits.

13. The device of claim 1 , further comprising:

a first transform unit configured to perform a first transform operation on a reference channel to generate the frequency-domain reference channel; and

a second transform unit configured to perform a second transform operation on a target channel to generate the frequency-domain target channel.

14. The device of claim 1 , further comprising a mid channel encoder configured to encode the mid channel as part of the bitstream.

15. The device of claim 1 , wherein the residual channel comprises an error channel signal.

16. The device of claim 1 , wherein the residual generation unit and the residual scaling unit are integrated into a wireless device.

17. The device of claim 1 , wherein the residual generation unit and the residual scaling unit are integrated into a base station.

18. A method of communication, the method comprising:

performing a down-mix operation, based on a frequency-domain reference channel and a frequency-domain target channel, to generate a mid channel and a side channel;

generating a predicted side channel based on the mid channel, the predicted side channel corresponding to a prediction of the side channel;

generating a residual channel based on the side channel and the predicted side channel;

determining a scaling factor based on a temporal misalignment between the frequency-domain reference channel and the frequency-domain target channel;

scaling the residual channel by the scaling factor to generate a scaled residual channel; and

encoding the scaled residual channel as part of a bitstream.

19. The method of claim 18 , further comprising determining an inter-channel mismatch value indicative of the temporal misalignment between the frequency-domain reference channel and the frequency-domain target channel, wherein the scaling factor is based on the inter-channel mismatch value.

20. The method of claim 19 , wherein one or more bands of the residual channel are zeroed out based on the inter-channel mismatch value.

21. The method of claim 19 , wherein each band of the residual channel is zeroed out based on the inter-channel mismatch value.

22. The method of claim 19 , further comprising setting a number of bits used to encode the residual channel in the bitstream based on the inter-channel mismatch value.

23. The method of claim 19 , further comprising comparing the inter-channel mismatch value to a threshold, wherein, if the inter-channel mismatch value is less than or equal to the threshold, a first number of bits is used to encode the scaled residual channel.

24. The method of claim 18 , wherein scaling the residual channel is performed at a wireless device.

25. The method of claim 18 , wherein scaling the residual channel is performed at a base station.

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

performing a down-mix operation, based on a frequency-domain reference channel and a frequency-domain target channel, to generate a mid channel and a side channel;

generating a predicted side channel based on the mid channel, the predicted side channel corresponding to a prediction of the side channel;

generating a residual channel based on the side channel and the predicted side channel;

determining a scaling factor based on a temporal misalignment between a frequency-domain reference channel and a frequency-domain target channel;

scaling the residual channel by the scaling factor to generate a scaled residual channel; and

encoding the scaled residual channel as part of a bitstream.

27. The non-transitory computer-readable medium of claim 26 , wherein the residual channel comprises an error channel signal.