Method and apparatus to determine encoding mode of audio signal and method and apparatus to encode and/or decode audio signal using the encoding mode determination method and apparatus

An apparatus to decode a signal of a bitstream, comprising:

• at least one processor;
• and
• a determining unit to determine one of an audio encoding mode and a music encoding mode from a bitstream having an encoded signal and information on the audio encoding mode or the music encoding mode of the encoded signal, so that the encoded signal of the bitstream is decoded according to the audio encoding mode or the music encoding mode,
• wherein the audio encoding mode or the music encoding mode of the encoded signal has been determined using a mode determination threshold of the short-term feature for a current frame which is adaptively adjusted in a unit of frames by using a parameter generated from a long-term feature for the current frame.

An apparatus to encode and/or decode an audio signal, comprising:

• at least one processor;
• a first determining unit to generate a short-term feature and a long-term feature for a current frame, to generate a parameter by using the long-term feature, to adaptively adjust a mode determination threshold of the short-term feature in a unit of frames by using the parameter and to determine one of an audio encoding mode and a music encoding mode of the current frame based on a comparison of the short-term feature and the adjusted mode determination threshold, so that the current frame of the audio signal is encoded according to the audio encoding mode or the music encoding mode;
• and
• a second determining unit to determine one of the audio encoding mode and the music encoding mode from a bitstream having the encoded signal and information on the encoding mode, so that the encoded signal of the bitstream is decoded according to the audio encoding mode or the music encoding mode.

An encoding apparatus for an audio signal, comprising:

• at least one processor;
• and
• a short-term feature generation unit to analyze the audio signal for a current frame and generating a short-term feature;
• a long-term feature generation unit to generate a long-term feature for the current frame using the short-term feature;
• a mode determination threshold adjustment unit to adaptively adjust a mode determination threshold for the current frame using a parameter obtained from the generated long-term feature;
• an encoding mode determination unit to determine one of an audio encoding mode and a speech encoding mode for the current frame using the adaptively adjusted mode determination threshold;
• and
• an encoding unit to perform frequency-domain encoding or time-domain encoding for the current frame in the determined encoding mode.