Stereo Encoding Method and Apparatus, and Stereo Decoding Method and Apparatus

A stereo encoding apparatus, comprising:

• at least one processor;
• and
• one or more memories coupled to the at least one processor and configured to store programming instructions that when executed by the at least one processor, cause the stereo encoding apparatus to:
• perform downmix processing on a left channel signal of a current frame and a right channel signal of the current frame to obtain a primary channel signal of the current frame and a secondary channel signal of the current frame;
• determine whether to perform differential encoding on a first pitch period of the secondary channel signal;
• and
• perform, when determining to perform the differential encoding, the differential encoding using a first estimated pitch period value of the primary channel signal to obtain a pitch period index value of the secondary channel signal,
• wherein the pitch period index value is for generating a to-be-sent stereo encoded bitstream.

A computer program product comprising instructions that are stored on a computer-readable medium and that, when executed by a processor, cause an apparatus to:

• perform downmix processing on a left channel signal of a current frame and a right channel signal of the current frame to obtain a primary channel signal of the current frame and a secondary channel signal of the current frame;
• determine whether to perform differential encoding on a first pitch period of the secondary channel signal;
• and
• perform, when determining to perform the differential encoding, the differential encoding using a first estimated pitch period value of the primary channel signal to obtain a pitch period index value of the secondary channel signal,
• wherein the pitch period index value is for generating a to-be-sent stereo encoded bitstream.