Encoding and decoding complex data

A method for encoding complex data, the method being performed in an encoder, the method comprising the steps of:

• obtaining an input signal made up of a series of numerically represented samples;
• determining a time frame of the input signal to process;
• applying a first window function on data in the time frame, resulting in first windowed data, wherein the first window function tapers sample magnitude towards the edges of the first window function;
• performing a windowed complex discrete Fourier-related transform on the first windowed data, resulting in frequency-domain data comprising a plurality of coefficients, keeping only the real part or the imaginary part of each coefficient;
• quantizing the frequency domain data resulting in quantized data;
• outputting the quantized data as encoded data;
• and
• repeating the method, wherein each subsequent iteration of the step of determining a time frame comprises determining a time frame that overlaps in time with a most recent preceding time frame.

An encoder for encoding complex data, the encoder comprising:

• a processor;
• and
• a memory storing instructions that, when executed by the processor, cause the encoder to:
• obtain an input signal made up of a series of numerically represented samples;
• determine a time frame of the input signal to process;
• apply a first window function on data in the time frame, resulting in first windowed data, wherein the first window function tapers sample magnitude towards the edges of the first window function;
• perform a windowed complex discrete Fourier-related transform on the first windowed data, resulting in frequency-domain data comprising a plurality of coefficients, keeping only the real part or the imaginary part of each coefficient;
• quantizing the frequency domain data resulting in quantized data;
• output the quantized data as encoded data;
• and
• repeat said instructions, wherein each subsequent iteration of the instructions to determine a time frame comprise instructions that, when executed by the processor, cause the encoder to determine a time frame that overlaps in time with a most recent preceding time frame.

A computer program product comprising a non-transitory storage medium including program code to be executed by at least one processor of an encoder, the computer program product comprising program code, whereby execution of the program code causes the encoder to:

• obtain an input signal made up of a series of numerically represented samples;
• determine a time frame of the input signal to process;
• apply a first window function on data in the time frame, resulting in first windowed data, wherein the first window function tapers sample magnitude towards the edges of the first window function;
• perform a windowed complex discrete Fourier-related transform on the first windowed data, resulting in frequency-domain data comprising a plurality of coefficients, keeping only the real part or the imaginary part of each coefficient;
• quantizing the frequency domain data resulting in quantized data;
• output the quantized data as encoded data;
• and
• repeat said instructions, wherein each subsequent iteration of the instructions to determine a time frame comprise instructions that, when executed by the processor, cause the encoder to determine a time frame that overlaps in time with a most recent preceding time frame.

A method for decoding encoded complex data, the method being performed in a decoder, the method comprising the steps of:

• obtaining encoded data for a time frame of data;
• unpacking quantization performed by the encoder;
• performing a windowed complex inverse discrete Fourier-related transform on the unpacked data, resulting in time-domain data;
• applying a fourth window on the time-domain data, resulting in fourth windowed data, wherein the fourth window function is determined based on a first window function applied in generating the encoded data;
• adding, in corresponding time units, the fourth windowed data to previously determined overlapping fourth windowed data of a preceding time frame;
• outputting, as output data, the added data for time units for which all encoded data has been processed as a series of numerically represented samples;
• and
• repeating the method, wherein each subsequent iteration of the step of obtaining comprises obtaining encoded data for a time frame that overlaps in time with a most recent preceding time frame.