Efficient and scalable parametric stereo coding for low bitrate applications

A method for decoding an encoded bitstream, the method comprising:

• demultiplexing, by a demultiplexer, the encoded bitstream for obtaining a lowband core decoder signal, level parameters, and balance parameters;
• producing, by a lowband decoder, a lowband output signal, the lowband output signal having a lowband mono signal or a lowband stereo signal;
• generating, by a high-frequency reconstruction device, a synthetic highband using the lowband output signal, the level parameters, and the balance parameters;
• combining the synthetic highband and the lowband output signal to form a combined signal, and
• outputting the combined signal,
• wherein the level parameters represent a total power in a frequency band of a signal having two channels,
• wherein the total power represents a sum of an energy of a left channel and an energy of a right channel for a given time segment and frequency band,
• wherein the balance parameters represent a quotient of an energy of the left channel and an energy of the right channel,
• wherein the level parameters are delta coded in time.

A decoder configured to decode an encoded bitstream, the decoder comprising:

• a demultiplexer for demultiplexing the encoded bitstream for obtaining a lowband core decoder signal, level parameters, and balance parameters;
• a lowband core decoder for producing a lowband output signal, the lowband output signal having a lowband mono signal or a lowband stereo signal;
• a high-frequency reconstruction device for generating a synthetic highband using the lowband output signal, the level parameters, and the balance parameters and for combining the synthetic highband and the lowband output signal to form a combined signal,
• a parametric stereo decoder for generating a stereo audio signal from the combined signal;
• and
• an output interface for outputting the stereo signal,
• wherein the level parameters represent a total power in a frequency band of a signal having two channels,
• wherein the total power represents a sum of an energy of a left channel and an energy of a right channel for a given time segment and frequency band,
• wherein the balance parameters represent a quotient of an energy of the left channel and an energy of the right channel,
• wherein the level parameters are delta coded in time.

A method for decoding an encoded bitstream, the method comprising:

• demultiplexing, by a demultiplexer, the encoded bitstream for obtaining a lowband core decoder signal, level parameters, and balance parameters;
• producing, by a lowband decoder, a lowband output signal, the lowband output signal having a lowband mono signal or a lowband stereo signal;
• generating, by a high-frequency reconstruction device, a synthetic highband using the lowband output signal, the level parameters, and the balance parameters;
• combining the synthetic highband and the lowband output signal to form a combined signal;
• generating a stereo signal from the combined signal;
• and
• outputting the stereo signal,
• wherein the level parameters represent a total power in a frequency band of a signal having two channels,
• wherein the total power represents a sum of an energy of a left channel and an energy of a right channel for a given time segment and frequency band,
• wherein the balance parameters represent a quotient of an energy of the left channel and an energy of the right channel,
• wherein the level parameters are delta coded in time.