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

US5740317A · kind A · utility

Assignee

• Institut Fur Rundfunktechnik GMBH · DE

Inventors

• Robert Sedlmeyer · Ismaning, DE
• Andreas Brefort · Krefeld, DE
• Jens Groh · Munich, DE
• Wolfgang Krafft · Munich, DE
• Klaus Rosinski · Hersbruck, DE
• Detlef Wiese · Goldach, DE
• Gerhard Stoll · Winnenden, DE
• Martin Link · Merdingen, DE

Key dates

• Filing date: Aug 30, 1995
• Grant date: Apr 14, 1998
• Expiry date: Aug 30, 2015

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04B1/665
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

Source 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 e…