Process for finding the overall monitoring threshold during a bit-rate-reducing source coding

摘要

PCT No. PCT/EP92/01658 Sec. 371 Date Sep. 17, 1993 Sec. 102(e) Date Sep. 17, 1993 PCT Filed Jul. 21, 1992 PCT Pub. No. WO93/02508 PCT Pub. Date Feb. 4, 1993Source coding digitized audio signals includes providing time or spectral domain sampling values of the digitized audio signal, requantizing the sampling values according their permissible quantizing noise as determined by a coding and requantizing control signal, and multiplexing the control signal and the requantized sampling values into a time multiplex frame depending on the bit rate reduction employed. The coding and requantizing control signal is determined from the sampling values by determining the global masking effect from all relevant maskers which are tonal maskers and noise maskers, and which result from the sampling values, and from a silence audio threshold. The global masking effect is determined by segmenting masking edges of possible maskers and approximating in individual segments with lower order polynomials, and determining coefficients of the lower order polynomials, converting the maskers into logarithmic levels and using intensities of the maskers to determine the coefficients of the lower order polynomials, and determining the global masking threshold, step-wise, masker by masker, at individual possible base points, from the polynomials describing masking edges of the possible maskers.