Please download the dossier by clicking on the dossier button x
×

Sound quality of established low bit-rate audio coding systems without loss of decoder compatibility

  • US 6,226,616 B1
  • Filed: 06/21/1999
  • Issued: 05/01/2001
  • Est. Priority Date: 06/21/1999
  • Status: Expired due to Term
First Claim
Patent Images

1. A multi-channel audio encoder for coding a digital audio signal sampled at a known sampling rate and having an audio bandwidth, comprising:

  • a core encoder having a sampling rate and audio bandwidth less than that of said digital audio signal;

    an extension encoder having a sampling rate and audio bandwidth equal to that of said digital audio signal;

    a decimation low pass filter (LPF) that filters the digital audio signal to remove signal components above the audio bandwidth of the core encoder;

    a decimator that down samples the filtered signal to extract a core signal whose sampling rate matches the core encoder, wherein said core encoder codes the core signal into core bits;

    a core decoder that decodes the core bits to form a reconstructed core signal;

    an interpolator that upsamples the reconstructed core signal to the extension encoder sampling rate;

    an interpolation LPF that filters the upsampled reconstructed core signal to remove interpolation aliasing; and

    a summing node that subtracts the filtered signal from the digital audio signal to form a difference signal, wherein said extension encoder encodes the difference signal into extension bits.

View all claims
  • 8 Assignments
Timeline View
Assignment View
    ×
    ×