Method and device for audio band-width detection and audio band-width switching in an audio codec

A device for detecting, in an encoder part of a sound codec including a sound signal front pre-processing stage followed by a sound signal MDCT (Modified Discrete Cosine Transform) core encoding stage, an audio band-width of a sound signal to be coded, comprising:

• at least one processor;
• and
• a memory coupled to the processor and storing non-transitory instructions that when executed cause the processor to implement:
• an analyser of the sound signal, integrated to the MIDCT core encoding stage, for analysing a MDCT spectrum of the sound signal;
• and
• a final audio band-width decision module integrated to the front pre-processing stage for delivering a final decision about the detected audio band-width using the result of the analysis of the MIDCT spectrum of the sound signal;
• wherein, in the encoder part of the sound codec, the final audio band-width decision module integrated to the front pre-processing stage is located upstream of the sound signal analyser integrated to the MDCT core encoding stage and wherein, in operation, the result of the analysis of the MIDCT spectrum of the sound signal by the sound signal analyser in a current frame is used by the final audio band-width decision module in a next frame following the current frame to deliver the final decision about the detected audio band-width of the sound signal.