Audio encoding device, method and program, and audio decoding device, method and program
An audio packet error concealment system includes an encoding unit for encoding an audio signal consisting of a plurality of frames, and an auxiliary information encoding unit for estimating and encoding auxiliary information about a temporal change of power of the audio signal. The auxiliary information is used in packet loss concealment in decoding of the audio signal. The auxiliary information about the temporal change of power may contain a parameter that functionally approximates a plurality of powers of subframes shorter than one frame, or may contain information about a vector obtained by vector quantization of a plurality of powers of subframes shorter than one frame.
1. An audio encoding device for encoding an audio signal consisting of a plurality of frames, the audio encoding device comprising:
an audio encoding unit for encoding the audio signal; and
an auxiliary information encoding unit for estimating and encoding auxiliary information about a temporal change of power of the audio signal, the auxiliary information being used in packet loss concealment in decoding of the audio signal,
wherein the auxiliary information encoding unit estimates and encodes a flag of sudden change of power of an audio signal of a frame different than the current encoded frame by the audio encoding unit, as the auxiliary information,
when the flag indicates a predetermined mode, the auxiliary information encoding unit further estimates and encodes quantized transient power at a position of the sudden change of the frame different than the current encoded frame, as the auxiliary information, wherein the auxiliary information contains only the flag and the quantized transient power, and
when the flag does not indicate the predetermined mode, the auxiliary information encoding unit does not include the quantized transient power in the auxiliary information.
2. An audio encoding method executed by an audio encoding device for encoding an audio signal consisting of a plurality of frames, the audio encoding method comprising:
an audio encoding step of encoding the audio signal; and
an auxiliary information encoding step of estimating and encoding auxiliary information about a temporal change of power of the audio signal, the auxiliary information being used in packet loss concealment in decoding of the audio signal,
wherein in the auxiliary information encoding step, the audio encoding device estimates and encodes a flag of sudden change of power of an audio signal of a frame different than the current encoded frame by the audio encoding step, as the auxiliary information,
when the flag indicates a predetermined mode, the audio encoding device further estimates and encodes quantized transient power at a position of the sudden change of the frame different than the current encoded frame, as the auxiliary information, wherein the auxiliary information contains only the flag and the quantized transient power, and
when the flag does not indicate the predetermined mode, the audio encoding device does not include the quantized transient power in the auxiliary information.