Encoding device, decoding device, and methods therein

A decoding apparatus, comprising:

• a first decoder that generates a first decoded signal by decoding first encoded information relating to a first channel signal;
• a second decoder that generates a decoded error signal by decoding second encoded information relating to a second channel signal;
• an adaptive filter that generates the predicted signal by performing filter processing on the first decoded signal and uses the first decoded signal and the decoded error signal to update filter coefficients used in the filter processing;
• a storage that stores the filter coefficients;
• a detector that detects presence/absence of transmission error and generates a detection result as first detection information;
• a measurer that counts an elapsed time since the detection result indicated that presence of transmission error was detected;
• and
• a first switch that connects the storage and the adaptive filter when the elapsed time matches a predetermined time;
• wherein, when the first switch connects the storage and the adaptive filter, the adaptive filter receives filter coefficients of the past from the storage and performs the filter processing using the filter coefficients of the past as the filter coefficients of the adaptive filter;
• a change detector section that detects presence/absence of change of a sense of stereo of the first channel signal and the second channel signal and generates second detection information;
• and
• a second switch that switches a connection state from the adaptive filter to the storage based on the second detection information, wherein:
• when the second detection information indicates presence of change of the sense of stereo, the second switch connects the adaptive filter and the storage;
• and
• when the second switch connects the adaptive filter and the storage, the storage stores the filter coefficients updated in the adaptive filter.

An encoding method, comprising:

• generating first encoded information by encoding a first channel signal;
• generating a first decoded signal by decoding the first encoded information;
• performing filter processing on the first decoded signal with an adaptive filter and generating a predicted signal of the second channel signal;
• generating an error signal by obtaining an error between the second channel signal and the predicted signal;
• generating second encoded information by encoding the error signal;
• generating a decoded error signal by decoding the second encoded information;
• using the first decoded signal and the decoded error signal to update the filter coefficients of the adaptive filter;
• and
• storing the updated filter coefficients to a memory;
• first switching, by a first switch, a connection state from the memory to the adaptive filter, based on first detection information indicating presence/absence of transmission error, wherein, when the memory and the adaptive filter are connected in the first switching step, the adaptive filter receives the filter coefficients of the past from the memory to use the filter coefficients of the past as the filter coefficients of the adaptive filter and performs the filter processing;
• detecting presence/absence of change of a sense of stereo of the first channel signal and the second channel signal and generating second detection information;
• and
• second switching, by a second switch, a connection state from the adaptive filter to the memory based on the second detection information, wherein:
• when the second detection information indicates presence of change of the sense of stereo, the second switch connects the adaptive filter and the memory;
• and
• when the second switch connects the adaptive filter and the memory, the memory stores the filter coefficients updated in the adaptive filter.

A decoding method, comprising:

• generating a first decoded signal by decoding first encoded information relating to a first channel signal;
• generating a decoded error signal by decoding second encoded information relating to a second channel signal;
• generating the predicted signal by performing filter processing on the first decoded signal with an adaptive filter and uses the first decoded signal and the decoded error signal to update filter coefficients used in the filter processing;
• and
• storing the updated filter coefficients to a memory;
• detecting presence/absence of transmission error and generating detection result as first detection information;
• counting an elapsed time since the detection result indicated that presence of transmission error was detected;
• and
• first switching, by a first switch, a connection of connecting the memory and the adaptive filter when the elapsed time matches a predetermined time,
• wherein, when the memory and the adaptive filter are connected in the first switching step, the adaptive filter receives the filter coefficients of the past from the memory to use the filter coefficients of the past as the filter coefficients of the adaptive filter and performs the filter processing;
• in the filtering step detecting presence/absence of change of a sense of stereo of the first channel signal and the second channel signal and generates second detection information;
• and
• second switching, by a second switch, a connection state from the adaptive filter to the memory based on the second detection information, wherein:
• when the second detection information indicates presence of change of the sense of stereo, the second switch connects the adaptive filter and the memory;
• and
• when the second switch connects the adaptive filter and the memory, the memory stores the filter coefficients updated in the adaptive filter.