Method and apparatus of performing sample rate conversion of a multi-channel audio signal

A method of converting a first digital audio signal at a first sampling rate to a second digital audio signal at any of a plurality of sampling rates that are higher than said first sampling rate, said method comprising:

• storing a fixed set of filter coefficients as a plurality of phased subsets of filter coefficients;
• up-sampling said first digital audio signal by an up-sampling factor to generate an up-sampled audio signal;
• low-pass filtering said up-sampled audio signal by applying samples of said first digital audio signal to at least two phased subsets of said plurality of phased subsets of filter coefficients to generate at least two filtered samples of said filtered audio signal;
• and
• down-sampling said filtered audio signal by any of a plurality of down-sampling factors corresponding to said plurality of sampling rates, wherein each of said plurality of down-sampling factors is lower than said up-sampling factor, to generate said second digital audio signal at any of said plurality of audio sampling rates, wherein said down-sampling comprises linear interpolating between said at least two filtered samples to generate at least one interpolated output sample of said second digital audio signal.

Apparatus for converting a first digital audio signal at a first sampling rate to a second digital audio signal at any of a plurality of sampling rates that are higher than said first sampling rate, said apparatus comprising:

• a memory storing a fixed set of digital filter coefficients;
• a low-pass filter applying said fixed set of digital filter coefficients to said first digital audio signal to generate a filtered audio signal;
• and
• a linear interpolator generating an accumulated linear interpolation ratio and applying said accumulated linear interpolation ratio to said filtered audio signal to generate said second digital audio signal at any of said plurality of sampling rates wherein said plurality of sampling rates are higher than said first sampling rate.